Ardupilot Copter

Abbreviated Operators Manual

Preface: Operation instructions for the Ardupilot family of 

autopilot control systems are available in the form of on-line 

documents. The particular homepage relevant to the aircraft 

discussed in the exemption request can be found at: 

http://copter.ardupilot.com/ . 

For brevity purposes the following document contains excerpts 

from this on-line manual. It features relevant selections sufficient 

to support the exemption request, however, not all sections have 

been included on this particular document due to the extensive 

amount of material available. The instruction documents can be 

viewed in their entirety at: 

http://copter.ardupilot.com/ 
Copter > common-Table of Contents

Table of Contents

APM:Copter

 TOC

 Introducing Copter

 How Multicopters Work

 What You’ll Need

 MultiCopter Safety

 Choosing a MultiCopter Frame

 Choosing a Flight Controller

 Choosing a Ground Station

 Use-Case Overview

 First Time Setup

 Install Mission Planner

 Assembly

 Mounting the Flight Controller

 Pixhawk Wiring QuickStart

 Powering the Pixhawk

 Compatible RC Tx/Rx Systems (Pixhawk and PX4)

 Advanced Pixhawk Quadcopter Wiring Chart

 Erle-Brain2 Wiring Quick Start

 Compatible RC Transmitter and Receiver Systems (Erle-Brain 2)

 Connect ESCs and Motors

 Installing GPS+Compass Module

 Detailed Vehicle Builds

 DJI F330 FlameWheel QuadCopter

 Hoverthings Flip Sport Quadcopter

 3DR Kits and Best Practices

 Build Your Own Multicopter

 Advanced MultiCopter Design

 Improving the Capabilities of Your Multicopter

 Loading Firmware

 Connect Mission Planner to AutoPilot

 Configuring Hardware

 Frame Type Configuration

 Compass Calibration

 Radio Control Calibration

 Accelerometer Calibration

 RC Transmitter Mode Setup

 ESC Calibration

 First Flight

 Flight Modes

 Acro Mode

 Altitude Hold Mode
 Auto Mode

 Brake Mode

 Circle Mode

 Drift Mode

 Follow Me Mode (GSC Enabled)

 Guided Mode

 Land Mode

 Loiter Mode

 PosHold Mode

 Position Mode

 RTL Mode

 Simple and Super Simple Modes

 Sport Mode

 Stabilize Mode

 Pre-arm Safety Check

 Arming and Disarming

 Getting Off the Ground – Tips for New Operators

 Basic Tuning

 Measuring Vibration

 Setting Throttle Mid

 Save Trim & Auto Trim

 Failsafe Mechanisms

 Radio Failsafe

 Battery Failsafe

 GCS Failsafe

 EKF / DCM failsafe

 GPS Failsafe and Glitch Protection

 Simple GeoFence

 Pre-Flight Checklist

 Advanced Configuration

 Tuning

 AutoTune

 Roll and Pitch Tuning

 EKF Overview/Tuning

 Motor Thrust Scaling

 Advanced Tuning

 Compass Setup (Advanced)

 UBlox GPS Configuration

 Parameter Reset

 Auxiliary Function Switches

 Vibration Damping

 Current Limiting and Voltage Scaling

 RCMAP

 Sensor Testing

 Telemetry Port Setup

 Magnetic Interference

 Full Parameter List

 Mission Planning
 Planning a Mission with Waypoints and Events

 Copter Mission Command List

 Mission Command List

 Camera Control and Auto Missions in Mission Planner

 Rally Points

 Terrain Following

 Geotagging Images

 Mission Analysis

 Diagnosing problems using Logs

 Dataflash Logs

 Telemetry Logs

 Recording and Playing Back Missions

 Optional Hardware

 Telemetry

 RFD900

 SiK Radio v2

 Telemetry Radio Regional Regulations

 Configuring a Telemetry Radio

 Bluetooth

 FrSky telemetry

 XBee

 SiK Radio — Advanced Configuration

 3DR Radio v1

 Power Modules

 Smart Battery

 AttoPilot Current Sensor

 Mauch Power Modules

 AirbotPower Power Module

 3DR Power Module

 Power Module Configuration

 Rangefinders

 Maxbotic Analog Sonar (AC3.2)

 Maxbotix I2C Sonar

 LIDAR-Lite

 Lightware SF02 Lidar

 LightWare SF10 Lidar

 TeraRanger One Rangefinder

 Analog Sonar (AC3.1)

 Optical Flow Sensor

 ADNS3080 Mouse Sensor

 PX4-FLOW

 Cameras and Gimbals

 Tarot Brushless Gimbal

 SToRM32 Gimbal

 Gimbal with Servos

 Camera Shutter Configuration

 Camera Trigger using CHDK

 Camera Shutter Trigger Boards for Purchase
 Seagull #MAP (Sony MultiPort)

 SkySight MONO (Sony MultiPort)

 Stratosnapper (IR)

 CHDK Camera Control

 OSD for FPV

 Minim OSD

 Servo

 GPS/Compass

 3DR UBlox GPS + Compass

 Zubax GNSS: GPS, Compass, Barometer

 GPS – How it Works

 Relay Switch

 UAVCAN ESCs

 EPM Gripper (EPM688)

 PPM Encoder

 PPM Encoder Programming Guide

 Received Signal Strength Indication (RSSI)

 Parachute

 Joystick or Gamepad

 External LEDs

 Buzzer

 Landing Gear

 Precision Landing (IRLock)

 ADS-B Reciever

 Companion Computers

 Traditional Helicopters

 Suggested Parts List

 Mounting the APM/Pixhawk

 Connecting APM

 Connecting your TX/RX, servos and motors

 Configuration through the MP

 Tuning

 Pre-Flight Testing

 Loading the Firmware

 Using a Magnetometer

 Tricopter

 SingleCopter and CoaxCopter

 AutoPilot Hardware Options

 Pixhawk

 LEDs

 Safety Switch

 Sounds

 Pixracer

 NAVIO+

 Erle-Brain Linux Autopilot

 Qualcomm Snapdragon Flight Kit

 Parrot Bebop Autopilot

 Use-Cases and Applications
 3D Mapping

 Web Applications

 First Person View (FPV)

 Indoor Flying Guidelines

 Multi-Vehicle Flying

 Antenna Tracking

 Mission Planner Antenna Tracking

 Antenna Design Overview

 Simulation

 Appendix

 Glossary

 Wiki Editing Guide

 PDF Guides

 Troubleshooting

 Commercial Support

 UAS Training Centers

 Development Team

 Copter Project News

 Archived Topics

 APM 2.x

 Archived:APM2.x Wiring QuickStart

 Powering the APM2

 Connecting the Radio Receiver (APM2)

 LEDs

 PPM Encoder

 PX4FMU

 Archived:PX4 Wiring QuickStart

 PX4IO Overview

 Open Camera Control Board

 GPS Module (External)

 External Compass Module

 Disabling the Built In GPS on APM2

 VR Gimbal

 Using Xbee radios for telemetry with APM

 Quick Start for RTFs

 HIL Quad Simulator

 Traditional Helicopter Simulator – TradHeliHIL

 Archived: Installing the PX4FMU on a QuadCopter

 GPS Failsafe

 Documentation Tests

 Full Table of Contents
Copter > Introducing Copter

Introducing Copter

Contents [hide]

 1 Overview

 2 Key features

 3 Getting started

 4 The development team

 5 Learn more about Copter

Overview

Copter is an advanced open-source autopilot system for multicopters, helicopters, and other rotor 

vehicles offering both enhanced remote control flight (via a number of intelligent flight modes) 

and execution of fully autonomous missions. 

As part of the DroneCode Software Platform it works seamlessly with Ground Control Station 

software that can monitor vehicle telemetry and perform powerful mission planning activities. It 

also benefits from other parts of the DroneCode platform, including simulators, log analysis 

tools, and higher level APIs for vehicle management and control.

Copter is on the cutting edge of aerial robotics and intended for those people who want to try 

advanced technology, leading edge techniques and new flight styles. It is already a preferred 

platform for numerous commercially available ready-to-fly vehicles, and can easily be added to 

enhance your own DIY multirotor craft.
Key features

Key features include:

 High quality auto-level and auto-altitude control: Fly level and straight or use the awesome “simple 

flight” mode, which makes Copter one of the easiest multicopters to fly.

Don’t worry about keeping an eye on your multicopter’s orientation – just push the stick the way you 

want to go, and the autopilot figures out what that means for whatever orientation the copter is in, 

using its onboard compass. “Front”, “back” ... who cares!

 Automatic takeoff and landing: Flick a switch and watch Copter execute its mission completely 

autonomously, returning home and landing by itself when it’s done.

 “Loiter” mode.: Copter will hold its position using its GPS and altitude sensors.

 Return to launch: Flip a switch to have Copter fly back to the launch location automatically.

 Fail safety: Automatically detect when the vehicle loses transmitter contact (or is outside a defined 

geofence) and return to the launch point. Will also attempt to land safely if hardware failures are 

detected. 

 No programming required: Use the desktop Mission Planner software to load the autopilot (with just 

one click) and set up Copter. The Mission Planner (and other compatible ground stations) deliver 
visual displays for vehicle state, settings and telemetry, including a point-and-click mission planning 

interface.

 Missions with hundreds of GPS waypoints: Just point and click waypoints in a Mission Planner, and 

Copter will fly itself to them. You cautomate entire missions, including camera control! The only 

distance limits are those of your vehicle power supply.

 Mission planning while in flight: Using a two-way wireless connection, waypoints, mode changing, 

even changing the gains of every control parameter can be done from your laptop or mobile device –

even while Copter is in the air!

Getting started

If you’re using Copter on a ready-to-fly vehicle then it is likely that it will be already setup, 

configured and tuned, ready for your first flight. We recommend you read your manufacturer’s 

instructions, particularly those related to safely, before flying. 

Once you’re familiar with your vehicle’s default setup you may want to configure your RC 

transmitter/vehicle to use more challenging flight modes, or choose a ground station and start 

flying automated missions. 

Tip:

Whether using an RTF or DIY vehicle, autonomous vehicles are potentially dangerous! Always follow 

best safety practices and pay close attention to all safety warnings.

If you’re working on a DIY project, this wiki has everything you need! You should start by 

reading this section in order to understand what a multicopter can do, and how to select a frame, 

flight controller board, and other essential components. You can then proceed to First Time 

Setup to learn how to assemble your Copter and then First Flight to learn how to configure and 

tune it.

The development team

Copter is developed and maintained by a dedicated group of volunteers from the open source 

community. Follow their continuing efforts and read about new project developments at 

DIYDrones.com.

All of us involved with this project care a great deal about the privacy and safety of those whom 

we share this planet with. Please be a good steward of this technology. It is the product of many 

evenings and weekends, we make it available for benevolent use.

Learn more about Copter
To find out more about Copter and your main configuration decisions, please see the topics 

below:

 How Multicopters Work

 What You'll Need

 MultiCopter Safety

 Choosing a MultiCopter Frame

 Choosing a Flight Controller

 Choosing a Ground Station

 Use-Case Overview

Copter > common-APM 2.5 and 2.6 Overview

APM 2.5 and 2.6 Overview

Contents [hide]

 1 APM 2.5

 2 APM 2.6

 3 Using the APM 2.5/2.6 Enclosure

 4 Not using the APM Enclosure

 5 Powering the APM2

 6 Explanation of solder jumper options on the bottom of the board

 6.1 Changing your telemetry to use UART2 (aka Serial3)

 6.2 APM 2.5 Board Features

 6.3 APM 2.5 Board Assembly Options

 7 Analog input pins

 8 Digital output pins

APM 2.5

The APM 2.5 board requires no assembly, and is ready for firmware. You have a choice of side 

or top entry pin configuration, in order to accommodate a variety of installations. You’ll see this 

option when you order.

***Click and drag the image above to spin it!

This page gives you a look under the hood, and goes into more detail about the design of this 

board.
The APM 2.5 has some improvements over the APM 2.0, but they both have a very similar 

layout and function.

APM 2.6

 APM 2.6 is a revision of the APM that makes use of an external compass.

 The APM 2.6 has no on board compass, and is optimized for vehicles where the compass 

should be placed as far from power and motor sources as possible to avoid magnetic 

interference.

 APM 2.6 is designed to be used with the 3DR GPS uBlox LEA-6 with Compass module.

 The GPS/Compass module may be mounted further from noise sources than the APM itself.

 APM 2.6 requires a GPS unit with an on board compass for full autonomy.

 For information on installing a 3DR GPS uBlox LEA-6 with Compass, visit .
Using the APM 2.5/2.6 Enclosure

The APM 2.5/2.6 board is shipped in an enclosure with foam protecting the barometric pressure 

sensor, as shown here.

Not using the APM Enclosure

If you aren’t using the enclosure, make sure to cover the barometric sensor with some open cell 

foam, cotton padding or tissue to protect it from prop wash, wind and turbulence. Also, the 

barometric sensor is sensitive to light and readings can change by several meters from direct 

sunlight to shade. Some type of light shield (on top of the foam) will minimize the effects of 

light changes.
Powering the APM2

The most common way to power the APM2 is to use the 3DR Power Module.

Detailed information on powering the APM and providing power to Servos is provided in 

Powering the APM2.

Explanation of solder jumper options on the bottom of 

the board
Changing your telemetry to use UART2 (aka Serial3)

By default an Xbee connected to the APM2 will use UART0 (aka “Serial” in Arduino) which is 

shared with the USB as mentioned above. If you wish to instead use UART2 (aka “Serial3”) for 

telemetry you can change the “AutoMUX UART0” jumper on the bottom of the APM2.

Although difficult to see, by default there are two small jumpers between the upper pads that 

must be cut with an X-Acto blade. Then a new solder bridge must be made to join the bottom 

pads.
APM 2.5 Board Features

APM 2.5 Board Assembly Options
 Quadzimodo has produced a really nice editable 3D model of the APM 2.5 board in SketchUp 

8: APM 2.5 Google Sketchup File
Analog input pins

Pin 0 to 8: The APM2 has a row of analog input pins down one side, labelled A0 to A8 on the 

underside of the board. These are available as pin numbers 0 to 8 inclusive in PIN variables.

All these pins can take up to 5V and may be used for any general analog input. They are 

commonly used for airspeed and sonar inputs.

Pin 12: power management connector current pin, accepts up to 5V, usually attached to 3DR 

power brick with 17:1 scaling

Pin 13: power management connector voltage pin, accepts up to 5V, usually attached to 3DR 

power brick with 10.1:1 scaling

Digital output pins

The APM2 uses the same set of 9 analog input pins as digital output pins. They are configured as 

digital output pins automatically when you start to use them as digital outputs.

Pin 54 to 62: You need to add 54 to the pin number to convert from an analog pin number to a 

digital pin number. So pin 54 is digital output pin on the A0 connector. Pin 58 is A4 etc.

These pins are usually used with the RELAY_PIN to RELAY_PIN4 parameters, allowing you to 

control things like camera shutter, bottle drop etc. They are also used as sonar “stop” pins 

allowing you to have multiple sonars and not have them interfere with each other.
Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues and 

suggestions may be posted on the forums or the Github Issue Tracker. 

APM2.x Wiring QuickStart

APM2.x Wiring QuickStart

This article explains how to write up Plane’s essential components when using the APM2.x 

Flight Controller. The instructions for adding other hardware are covered in Optional Hardware.

Contents [hide]

 1 Overview

 2 Example Wiring Diagram

 3 Inputs

 4 Reassigning your RC transmitter stick channels:

 5 Outputs

 6 Powering the plane

 6.1 Power Input

 7 Installing it in your plane

 8 Connecting GPS Module

 8.1 3DR GPS uBlox with Onboard Compass

 8.2 3DR GPS uBlox without Onboard Compass

 8.3 Tips on mounting the GPS module

Overview

Turning a RC plane into a UAV is essentially just a matter of putting an autopilot between the 

RC receiver and the aircraft’s servos, so the autopilot can take over control.

The way we do that is to plug female-to-female cables from the RC receiver into APM2’s inputs, 

and plug the servos (and motor controller for electric aircraft) into APM2’s outputs.

What you’ll need:

 At least a 5-channel RC unit. 7 channels or more is highly recommended

 Female-to female cables for each channel you’ll be using. These are fine.
 For APM2.0 you will need a power source. For electric aircraft, this is usually the ESC. For gas/nitro 

powered planes, your radio will need its own battery/BEC. ArduPilot Mega normally gets its power 

from the RC system.

 For APM2.5 you can use the supplied APM Power Module for the power source. 

Warning:

You still need an ESC or BEC to power the servos 

Note:

You can also power APM 2 from the USB cable. However, this will not power the RC output pins, so if 

you want to see servos move while testing APM 2 on the bench, you’ll need to connect a battery 

(through an ESC) to one of the output channels. It’s fine to have both an ESC and the USB cable 

connected at the same time.

Example Wiring Diagram

Example Wiring Diagram for a Bixler plane with APM

Example Wiring Diagram for a Bixler plane with APM
Inputs

Connect your RC receiver to APM2’s Inputs with female-to-female cables in the order shown 

above. Each channel that you want APM to control should be connected to an Input on the APM 

board. Typically, the Mode Switch (APM Input 8 for !Plane) is connected to any RC receiver 

channel that you have assigned to a three-position toggle switch on your RC transmitter (for 

most people, that’s channel 5).

Note:

These instructions are for Plane. Copter’s mode switch goes to APM input 5, not input 8

The ground (black) side of each connector should be on the outside, closest to the edge of the 

board, as shown here with either straight or right-angle connectors:
See also Connecting the Radio Receiver.

Note:
Elevons (combined ailerons/elevator, as used in flying wings) are also supported’ just connect them to 

the first two channels as you would to your RC receiver. You’ll tell APM to do elevon mixing in the 

Mission Planner setup process.

If you’re flying a V-tail, please see the VTAIL_OUTPUT option in the servo setup 

documentation.

Reassigning your RC transmitter stick channels:

 Although the default normal transmitter stick configuration is generally the best, Plane does allow 

you to reconfigure them.

 To reassign the RC transmitter sticks to other than the default channels: 

 Connect your APM’s USB port to your computer and start Mission Planner and Select the 

“Connect” button on the upper right..

 Select the “Configuration” tab then select “Advanced Params” and the Adv Parameter List”.

 Scroll down to the “RCMAP_ROLL, RCMAP_PITCH, RCMAP_THROTTLE and RCMAP_YAW” 

parameters.

 These allow you to directly assign which radio channel (1-8) is assigned to each of the major flight 

functions.

 This is useful when you have a flight transmitter with unusual channel assignments. 

 Or which does not allow easy channel reassignment at the transmitter

 Additional information on these parameters may be found (Here!)

Outputs

Plug your servos and other devices you want APM to control into the matching Output 

connectors as shown below.
Four channel setup:

1. Aileron

2. Elevator

3. Throttle

4. Rudder

Elevon setup. At this stage its not critical which channel is plugged into which elevon. They can 

be swapped around later if needs be:

1. Starboard (right) elevon
2. Port (left) elevon

3. Throttle

Powering the plane

The easiest way to power the APM2.x is using a 3DR Power Module with a LiPo battery.

The Power Module will not power servos and other peripherals. For more 

information/alternatives see Powering the APM2.

Power Input

Single Supply

Power Options Nominal Abs MAX JP1 status

Power on Output PWM connector 5.37V +-0.5 6V JP1 connected

Dual Supply

Power Options Nominal Abs MAX JP1 status

Power on Output PWM connector 5.00V +-0.5 6V JP1 open

Power on Input PWM connector 5.00V +-0.25 5.5V JP1 open

Note:

If JP1 open, separate power is required on both Input PWM and Output PWM.

Warning:

Do not exceed Abs MAX input voltages when connecting power supply or you will damage your board.

Warning:
Connecting USB when you have input voltages at the high end of the range (near Abs Max) can damage 

the board. Disconnect battery before connecting USB or test input voltages so they are within the 

normal specified range.

Installing it in your plane

When you place APM in your aircraft, it is very important that it face the right way. The GPS 

connector should face forward, and the servo cables face back. The board must also be right side 

up, with the IMU shield at the top. Like this (note: there’s a little arrow on the bottom of the 

shield that point to the front, too, in case you need a reminder at the field):

When putting APM in your plane, it’s important to ensure that it’s solidly mounted and doesn’t 

move around in flight. It should also be as close as possible to level when the plane is in its 

flying orientation. Ideally, you’ll want to have it as close to the center of gravity as you can 

(that’s where vibration is the least) and mounted on foam tape onto a solid platform.

Connecting GPS Module

A GPS module provides enhanced positioning for autonomous flight. Connecting your GPS to 

your autopilot by following these steps.
3DR GPS uBlox with Onboard Compass

3DR GPS uBlox with Onboard Compass is intended for use with APM 2.5 (for external 

compass). It provides enhanced compass performance because of the freedom to situate the GPS 

unit in an optimal position independent of the location of the APM. Place your GPS on the 

outside of your plane with a clear view of the sky, as far as possible from the motor and ESC, 

with the arrow facing forward.

Connect the GPS module to the APM 2.6 using the two cables included with the GPS as shown 

below.
3DR GPS uBlox with Onboard Compass includes two connector cables: one 4-position cable and 

one 5-position-to-6-position cable. To connect the GPS module to APM 2.6, connect the GPS to 

the APM GPS port using the 5-position-to-6-position cable; connect the GPS to the APM I2C 

port using the 4-position cable.

3DR GPS uBlox without Onboard Compass

3DR GPS uBlox without Onboard Compass is intended for use with APM 2.5. To install your 

GPS module without compass, mount to the outside of your plane with a clear view of the sky 

and connect to the APM 2.5 GPS port using the 5-position-to-6-position connector cable.

Tips on mounting the GPS module

 It doesn’t matter which way the GPS module is oriented, as long as the square antenna side is facing 

up

 It’s best to mount the GPS as far away from radio transmission equipment (like your telemetry or 

video transmitters) as possible.

 Ideally, the GPS module will have a clear view of the sky. On top of your plane is a good choice.

Here’s an example of one way to mount APM (and the GPS module) in an EasyStar using the 3D 

Robotics Electronics Chassis for the HobbyKing Bixler.

Chassis:
With equipment mounted:

Connecting everything for Arducopter

6/3/2012 

8 Comments 

Before you can configure your Arducopter, you will need to first connect everything together. This guide will show 

you all the cables and parts that you will need to connect to your arducopter.

Typical Quadcopter Layout

Please note the illustration Below highlights a (TYPICAL) installation. It contains optional equipment including 

a Camera Gimbal and a Battery Monitor and it utilizes an ESC wired "Y" power connection rather than the power 

distribution board common to many MultiCopters.

1. Connecting your motors and RC gear
Overview of connections on the Ardupilot Mega v2 board

Note: the instructions below are for regular RC receivers with 

PWM output (one cable per channel). If you're using a "PPM" 

receiver (one cable carries all channels), follow the 

instructions here.

Before you can configure your Arducopter, you will need to 

first connect everything together. This is quite easy. You need 

to connect your RC receiver to the Input side of the 

board. You can use the cables included with your Arducopter 

Kit, or if you are using another frame, you can use jumper 

cables, or female to female servo cables

Connections between RC receiver and Ardupilot Mega v2 board

If you are using female to female servo 

cables, the ground (black) side of each connector 

must be on the outside for the board, the signal 

(white/orange) needs to be on the inside as shown 

below.

Connecting with straight connectors

If you are using a multi-pin connector that was included 

with your Arducopter Kit, connect them as shown below

Connecting with right angle connectors
Input Side for RC receiver Output side to PDB

Please note, that your ESC, connectors should be plugged in the output side, it is suggested that you only use power 

from one of your ESC's. This can be dune by cutting the red wire on all but one of the ESC's, or by using a special 

adaptor.

2. Connecting ArduCopter motors

Once again if you are using an Arducopter Kit, with 

the PDB, then you dont need to worry about this if 

you soldered everything correctly as the motors are 

assigned to the correct pins with the cables you 

plugged connected in the previous step. However 

you will neet to make sure your motors are spinning 

in the correct direction. The images below show the 

possible arducopter configurations with correct 

motor orientation

Quick Tip: If your motor is not spinning in the correct 

direction, simply switch the position of any two of the 

ESC-motor wires.
Arducopter Quad Arducopter Tri

Arducopter Hexa, Octa, and Y6 Arducopter OCTA QUAD (X8)
Connecting a Roll-Tilt Cameramount

3. Connecting Optional Sensors

Sonar -Ultrasonic Rangefinder
AC2 supports the MaxSonar line of sonars for low level altitude hold and in the 

future collision avoidance. Below 10 meters sonar is primarily used for altitude 

hold. Above 10 meters, the barometric sensor is used. GPS is not required for 

altitude hold. 

The sonar sensors are quite sensitive to noise, adding something like a ferrite 

choke to your cable could help. The most important is to mount your sonar 

away from other electronics like ESC, or wireless telemetry modules.

Possible Causes of sonar Interferance

 Electrical noise caused by ESCs, Servos, or switching BEC's on the 

same circuit as the Sonar

 EMF radiation from motors, motor wires, ESC's or Xbee.

 Acoustic noise from propellers

Vibration from motors, props, etc.

Connect your Ultrasonic Sensor to the A0 port of your Ardupilot Mega v2 board
Optical Flow Sensor

The optical flow sensor is used to improve 

the position hold accuracy of your arducopter. This 

sensor is supported from Arducopter 2.6 and above.

Connecting the optical flow sensor to APMv2

 Power, GND, NCS pins should be attached to 

A3

 MISO, MOSI and SCLK pins should be directly 

soldered to the pins shown above

 Default mounting is lens pointing down, pins 

forward

Its a good idea to secure the wires with some cable 

ties so they dont break off over time
How to connect the optical flow sensor to your ardupilot mega board. Make sure the pins are facing forward
Copter > common-3DR Power Module

3DR Power Module

This page explains how to set up the 3DR Power Module (PM) to measure battery voltage and 

current consumption. The information will also be useful for setting up other types of Power 

Module.

Contents [hide]

 1 Overview

 2 Connecting the PM to a flight controller board

 3 Setup through Mission Planner

Overview

The Pixhawk and APM 2.x have a dedicated connector for attaching the 3DR Power Module

(PM). This is useful because it:

 Provides a stable 5.37V and 2.25Amp power supply which reduces the chances of a brown-out

 Allows monitoring of the battery’s voltage and current and triggering a return-to-launch when the 

voltage becomes low or the total power consumed during the flight approaches the battery’s 

capacity

 Allows the autopilot firmware to more accurately compensate for the interference on the compass 

from other components

The PM accepts a maximum input voltage of 18V (up to 4S Lipo battery) and maximum current 

of 90Amps. When used with an APM the full 90Amp current sensing range can be used, with the 

PX4/Pixhawks up to 60Amps can be measured.

There is more general information on powering in Powering the Pixhawk and Powering the 

APM2.

Warning:

The Power Module’s maximum input voltage is 18V. This is the maximum allowed by the on-board 

regulator. (4 cell LiPo max).

Warning:

The Power Module does not have sufficient power for servos or high current devices such as FPV 

transmitters.
 The power module does provide sufficient power for the Pixhawk/APM, your receiver and a small 

electronic module such as a PPM encoder or 3DR telemetry radio.

 You may “control” servos from signal pins, but the servos must be powered by a separate ESC.

Connecting the PM to a flight controller board

The 6-pos cable plugs into the 6-pos connector on both the Power Module and Pixhawk/APM.

 Pixhawk Power Port
 APM2.x Power Port

Your battery connects to the Power Module’s male connector, and its female connector plugs 

into your ESC or Power Distribution Board.

Note:

APM 2.x Power Module Notes:

 You should normally remove the APM’s JP1 jumper when using the Power Module so that only your 

APM board and your receiver are powered from the Power Module’s on-board regulator and not 

from your ESCs. 

 Removing the jumper allows you to use the APM’s servo output rail to distribute power from your 

ESC’s BEC or separate UBEC to any servos or external equipment.

 If you are using servos, plug an ESC BEC or stand alone UBEC power wire and ground wire into 

two of the power and ground pins on the APM’s servo output rail to provide a common power 

and ground bus for servo power.

 You can leave the jumper present if you are using ESCs that have no BECs or if all the ESC BECs power 

wires are cut and you are not powering any servos from the servo out rail.

 You can also individually power each servo from each individual ESC-BEC. 

 Simply run the power and ground from each ESC-BEC individually and directly to each servo (very 

handy for multicopters).

Setup through Mission Planner

Power Module Configuration in Mission Planner explains how to configure a Power Module and 

get low battery alerts from Mission Planner.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues and 

suggestions may be posted on the forums or the Github Issue Tracker. 
Copter > common-Powering the APM2

Powering the APM2

This article demonstrates the options for powering the APM2.x board along with information 

about the requirements for connecting the power rail.

Contents [hide]

 1 Overview

 2 APM power circuit

 3 Alternative ways to power your board

 4 Non-technical description of the power supply requirements

 5 Power supply rails connected requirements (JP1 Installed)

 5.1 No Power Module and no servos and power provided by BEC from ESC

 5.2 No Power Module but using servos and a high power External BEC

 5.3 No Power Module but using servos and multiple BECs from ESC’s (A BEC for each servo)

 6 Power supply rails not connected requirements (JP1 Not Installed)

 6.1 Power Module and no servos

 6.2 Power Module and using servos with external BEC power

 6.3 Power Module and using servos with BEC power from one ESC

 6.4 No Power Module and using Servos with BEC power from two ESCs

 7 APM Power Wiring Example

Overview

Like any computer, the APM needs a power supply with a steady clean voltage and sufficient 

current.

3DR provides an 3DR Power Module that supplies 2.25A at 5.37V. The module is designed to 

convert power from the main flight battery (18 Volt maximum). That module will supply 

sufficient power for your APM, and low power radios including your RC receiver (without 

servos). Your RC receiver can be powered from any APM Input (+5V and ground). This is 

normally done by connecting a 2 or 3 wire cable between an APM Input and one of the output 

channels on the RC radio.

If you are using any servos such as are required with a traditional helicopter or a camera gimbal, 

you will need to provide an additional dedicated power supply for the servos. The APM is 

intended to control servos, not power them.
The following sections describe the APM power circuit (you will need to understand this in order 

to design a power supply for your APM, or provide additional power), and your options for 

powering the APM and connected components.

APM power circuit

There are two “sides” to the positive circuit in the board. Each side has positive-rails available 

for inputing power or distributing it to peripheral devices. The center row of pins in the three 

groups of pins (Outputs, Inputs, Analog) labeled “+” are referred to as a “positive-rail”. This 

means that the base of all the + pins are connected so they represent a single electrical path. The 

positive-rails of the Input and Analog group are connected together. So we have two separate 

positive circuits, one in the Outputs and the other made up of the Input/Analog.

All of the components on the board take power from various points on these rails, so it is 

necessary for both “sides” to be receiving +5V (within the specs below) for the board to 

function.

These positive-rails can be joined together by placing JP1 in it’s position on the board. This 

connects all the positive-rails ands provides power to both sides of the board, so that low-level 

power can be distributed to peripheral sensors and devices: 3DR Radios, sonar, RC Rx, etc. via 

the power-rails.

When using the power module, the circuit path is as follows:
From the power module connection the negative wire is connected to a negative-rail shared by 

the entire board regardless of JP1.

Positive voltage comes in to a T-junction. to the left is a path through the JP1 to the positive-rail 

of the Outputs. To the right it flows through an over-voltage, over-current, reverse-polarity 

protection(500mA fuse and 6V Zener diode). A side effect of passing through the Zener diode is 

a .37V loss, therefore input voltage should be bumped up by .37V to account for this. From here 

the positive voltage runs to the positive-rails of the Inputs and Analog. Inputs should not be used 

to power anything except your RC receiver.

Higher current loads such as servos should be powered from the power-rails (positive-negative) 

of the Output side. You must use an adequate voltage-regulator to provide power directly to the 

Output power-rails, all servo power leads will attach to these same rails (the signal wires can 

connect on the Analog “S” pins in the case of a camera gimbal). Since JP1 is removed in this 

scenario, the other “side” of the board will need power provided to it’s power-rails directly.

Alternative ways to power your board

If you are using the 3DR Power Module please find instructions here: Using the 3DR Power 

Module

Warning:

Under no circumstances should you ever attempt to draw servo power from the analog input connector.

Warning:

You may “control” servos from A9, A10 and A11 from the A0 – A11 I/O connector, but you must run 

servo power separately.

 The A0 – A11 I/O connector cannot supply sufficient power for servos.

 A9, A10 and A11 of the I/O connector come pre-wired to correct digital out for use as servo control 

lines.

 For servo use, it is imperative that they have not been reassigned to analog use with the pads on the 

back of the APM board.

Non-technical description of the power supply 

requirements

The description below simply supplements and provides an alternate view of the information 

above.
1. The APM 2.5/2.6 board has two separate power circuits which make it very easy to power by a 

variety of methods. 

1. A fused power circuit provides primary board and general I/O power: (It cannot provide power for 

servos).

2. The Other power circuit is for the OUTPUT connector power rail: (it can provide power for 

servos).

2. The jumper JP 1 determines whether the two power circuits are connected or separate. 

1. If JP1 is removed, the power rail on the OUTPUT connector “Floats” and may be used to distribute 

power.

2. Although if JP1 is removed the OUTPUT connector cannot be used to supply power to the APM 

board.

3. It is possible to power the APM board from the Power Module connector or the OUTPUT or INPUT 

connectors.

4. Normally the APM 2.5/2.6 “Power Module” is used to provide primary APM 2.5 board and general 

I/O power.

5. Alternatively primary board power can be supplied by a BEC either from one of the ESCs or from an 

external BEC.

6. If servos are used, supplementary power is required. 

1. Generally one power supply is provided for the board and one or more additional power supplies 

for the servos.

2. But if a sufficiently large external BEC is used it can supply power for both via the OUTPUT 

connector.

7. Only the OUTPUT connector can provide power for servos as the other circuit is fused. 

1. The address connector is sometimes used provide servo signals, but the servos power must come 

from elsewhere.

8. How you are powering your APM board and or servos determines whether JP1 is installed or not. 

1. (Whether the two power circuits are separated or connected).

2. All possible configurations are detailed Below.

9. The type of use will determine which options are available. 

1. Copter can power the APM from a power module or a UBEC or a BEC from one of the ESCs and 

can power servos from a UBEC or from the other ESC’s BECs.

2. Plane can power the APM from the power module, the BEC from the flight motors ESC or 

a separate UBEC and can power servos from a separate UBEC or the flight motors BEC if it is large 

enough.

3. Rover can power the APM from the power module, the BEC from the drive motor’s ESC or 

a separate UBEC and can power the steering servo from a separate UBEC or the drive motors BEC 

if it is large enough.

Power supply rails connected requirements (JP1

Installed)

Warning:

Do not exceed Abs MAX input voltages when connecting the power supply or you will damage your 

board.
Warning:

Connecting USB when you have input voltages at the high end of the range (near Abs Max) can damage 

the board. Disconnect battery before connecting USB or test input voltages so they are within the 

specified range.

Power Options Nominal Abs MAX JP1 status

Power on Output PWM connector 5.37V +-0.5 6V JP1 connected

Power on Input PWM connector 5.00V +-0.25 5.5V JP1 connected

No Power Module and no servos and power provided by 

BEC from ESC

 If you do not have a power module and you are not using servos.

 Ensure JP1 is installed and provide the necessary power via the BEC from one of your ESC’s.

 Connect one ESC’s BEC power and ground wires to one pair of the APM OUTPUT connectors power 

and ground pins.

 Clip the BEC power leads on the remaining 3 wire connectors.

 Ensure that the ESC’s signal wires are connected to the appropriate APM OUTPUT connector signal 

pins.

 You must ensure that your ESC’s BEC has a sufficient power capability (at least 2 amps). 

 Most 20 amp or higher ESCs have 2 amp BECs.

No Power Module but using servos and a high power 

External BEC

 If you do not have a power module and are using servos you can use a high power external BEC.

 Ensure JP1 is installed and provide the necessary power via a high power external BEC (5 to 10 amps 

or more).

 The BEC power must be provided to one pair of the APM OUTPUT connector pins.

 Warning:

Clip all power leads on the ESC’s BECs (they would conflict with the external BEC).

 Your servos will determine the size of the BEC required.
 You should allow at least 2 or 3 amps extra to power the APM, receiver and to prevent (brown outs).

 All of the positive power for driving each servo must come from the OUTPUT connector. 

 This is true even if the servo(s) signal wires are connected to the ADDRESS connector.

 This option requires you to take responsibility for providing sufficient power to prevent brownout.

No Power Module but using servos and multiple BECs from 

ESC’s (A BEC for each servo)

 If you do not have a power module and are using servos you can use multiple BECs from your ESC’s.

 Ensure JP1 is installed and plug one of your ESC’s signal cables with power leads into the 

OUTPUT connector.

 Remove the power and ground leads from the remaining ESCs signal cable connectors.

 Plug the signal wire connector from each ESC onto the appropriate pin on the OUTPUT connector. 

 You can heat shrink these or plug them into a multi-wire connector appropriate for your copter.

 Connect one pair of each of the remaining BEC power and ground lines to the power and ground of 

each individual servo.

 Clip or heat shrink any remaining excess BEC power and ground leads.

 The BEC power from one ESC must be provided to one pair of the APM output connector pins.

 Plug only the signal input wire from your servos into the appropriate OUTPUT or ADDRESS connector 

pin.

 Your ESC’s BECs should be at least 2 amps.

 The ESC’s BEC grounds are in common with battery and internal signal ground so grounding the 

servos this way is OK.

Power supply rails not connected requirements (JP1

Not Installed)

Warning:

Do not exceed Abs MAX input voltages when connecting the power supply or you will damage your 

board.

Warning:

Connecting USB when you have input voltages at the high end of the range (near Abs Max) can damage 

the board. Disconnect battery before connecting USB or test input voltages so they are within the 

specified range.

Power Options Nominal Abs MAX JP1 status

Power on Output PWM connector 5.00V +-0.5 6V JP1 open
Power on Input PWM connector 5.00V +-0.25 5.5V JP1 open

Power Module and no servos

 If you have a power module and you are not using servos.

 Ensure JP1 is not installed.

 Provide the necessary power via the power module connected to the APM’s power module 

connector.

 When connecting your ESCs to the OUTPUT connector clip the BEC power leads on each ESC’s 3 wire 

connector. 

 Or connect only the ESC’s signal wires to the OUTPUT connector.

Power Module and using servos with external BEC power

 If you have a power module and an external BEC and you are using servos.

 Ensure JP1 is Not installed

 Provide APM board and receiver power via the power module connected to the power module 

connector.

 Connect an external BEC with sufficient power for your servos to one pair of the OUTPUT connector 

power pins.

 When connecting your ESCs to the OUTPUT connector clip the BEC power leads on each ESC’s 3 wire 

connector. 

 Or connect only the ESC signal wires to the OUTPUT connector.

Power Module and using servos with BEC power from one 

ESC

 If you have a power module and you are using servos Remove JP1.

 Provide APM and receiver power via the power module connected to the APM’s power module 

connector.

 The BEC of a single ESC must provide sufficient power for all your servos.

 When connecting your ESCs to the OUTPUT connector clip the BEC power leads on all but one of the 

ESC’s connectors.

 Or connect only the ESC signal wires to the OUTPUT connector for all except one ESC. 

 And on that ESC connect all 3 wires to the OUTPUT connector.

No Power Module and using Servos with BEC power from 

two ESCs
 If you do not have a power module and you are using servos remove JP1.

 Provide APM and receiver power via 1 pair of ESC-BEC power wires connected to the APM INPUT 

connector power pins.

 Also connect another of the ESCs power wire pair to the OUTPUT connector.

 The BEC of a single ESC must provide sufficient power for all your servos.

 Clip the signal power leads on your remaining ESC’s.

 Connect all ESC signal wires to the appropriate OUTPUT connector pins.

APM Power Wiring Example

Warning:

Do not exceed Abs MAX input voltages when connecting power supply or you will damage your board.

Warning:

Connecting USB when you have input voltages at the high end of the range (near Abs Max) can damage 

the board. Disconnect battery before connecting USB or test input voltages so they are within the 

specified range.

On the bench, you’ll probably be powering the board via your USB cable while you set it up and 

test it. But in your aircraft, you’ll need to power it with your on board power system, which is 

usually your LiPo battery going through an ESC or the Power Module. In the case of a 

multicopter, this can come through your Power Distribution Board (PDB), which will break out 

the 5V output from the one of the electronic speed controls (ESCs) or the Power module which is 

wored directly to the battery.

In the picture below, the red and black wires are the 5b m hV power cable coming from a PDB. 

You can plug them into any two pins along the 5V and Ground (middle and outer) rows of pins 

on APM 2.5’s Output side. The other cable, which in this case is a four-wire cable with orange 

and white wires for a quadcopter, is the signal cable to the PDB, which are the wires that APM 

2.5 will use to command each of the ESCs.

The picture below is of APM 2; but the concept is applicable to APM 2.5.
It’s also possible to power APM 2.5 from two separate sources, one powering the RC system on 

the input side, and the other powering the output side (servos or ESCs). This is determined by a 

jumper on the JP1 pins (see below). If the jumper is on, which is the factory default, the board is 

powered from the OUTPUT rail or the USB. If the jumper is off, the board is powered from the 

INPUT rail, but the OUTPUT rail will need its own power source. This configuration is used if 

you want to have two separate power sources in your aircraft, one powering the servos and the 

other powering the electronics. The ideal input voltage is 5.37v +/-0.0v and may not be provided 

by a typical ESC.

Warning:

Do not exceed Abs MAX input voltages when connecting power supply or you will damage your board.

In some cases it may be a good idea to set the input voltage slightly above the median (but below 

the maximum) to account for possible voltage drops during momentary high current events.

The APM2.5 by itself draws relatively little current (200ma range) and a power source capable 

of providing 300 – 500ma will provide plenty of margin. However, if servos or other power 
consuming devices are being driven by the same power source you must consider the power 

requirements for those devices as well and provide plenty of margin to prevent disastrous 

“brown-outs”. For instance, a single digital servo can easily draw 1-5 amps depending on it’s 

size and performance. (Note: ESCs do not consume power from the APM) If you experience 

spurious resets or other odd behavior it is most likely due to noisy or insufficient power to the 

APM. As with all logic boards, electrical noise from the motors, servos, or other high current 

devices on the power source can cause unpredictable behavior.

It is recommend that a power filter be used in such conditions.

Too short or long power wires, bad or old connectors, or insufficient current capability of the 

APM power source can result in a “brown-out” situation resulting in unpredictable operation. 

This is particularly true in traditional helicopters where the collective servos can draw 3-20 amps 

in short bursts. The power source must be able to accommodate this without voltage droop or 

voltage spikes. A quality switching type BEC (e.g one of these or one of these) can be a solution 

depending on overall current requirements. Many of these type of regulators are programmable 

so remember to program them with in the safe operating range of the APM2. Linear voltage 

regulators are not recommended as they are inefficient and prone to overheating and heat 

induced failures. APM2 should never be connected directly to a battery of any type.

Power source problems are common and can be insidious and frustrating. Be meticulous. Any 

autopilot or flight controller is useless and potentially dangerous without good clean power 

source.

The picture below is of APM 2; but the concept is applicable to APM 2.5/2.6.
Copter > common-Installing Mission Planner

Installing Mission Planner

Mission Planner is free, open source software available for Windows. These instructions will 

guide you through installing Mission Planner on your ground station computer.

Contents [hide]

 1 Download the most recent Mission Planner installer file

 2 Run the installation utility

 3 Open Mission Planner

 4 Updating Mission Planner

Download the most recent Mission Planner installer file

Go to the Mission Planner download page and click on the Download button to get the most 

recent Misson Planner installation file.

Run the installation utility
Open the Microsoft installer file (.msi) and select Run to run the installation utility.

Follow the instructions to complete the setup process. The installation utility will automatically 

install any necessary software drivers. If you receive a DirectX installation error, please update 

your DirectX plug-in from the DirectX Download Center.

If you receive the warning pictured here, select Install this driver software anyway to continue.
Mission Planner is normally installed in the C:\Program Files (x86)\APM Planner folder or 

the C:\Program Files\APM Planner folder. That is where your log files folder is located. 

An icon to open the Mission Planner is created according to your instructions during the 

installation.

Open Mission Planner

Once installation is complete, open Mission Planner by clicking on its system icon.

Then you can either:

 Connect Mission Planner to AutoPilot in order to receive telemetry and control the vehicle, or

 Load Firmware

Updating Mission Planner

Mission Planner automatically notifies you about available updates (when it is connected to the 

Internet).

Please always run the most current version of Mission Planner.
Copter > common-Loading Firmware onto Pixhawk/APM2.x/PX4

Loading Firmware onto 

Pixhawk/APM2.x/PX4

These instructions will show you how to download the latest firmware onto the Pixhawk, APM 

2.x or PX4 controller.

Contents [hide]

 1 Connect controller to computer

 2 Connect to Mission Planner

 3 Install firmware

 4 Testing

Connect controller to computer

Once you’ve installed the Mission Planner onto your computer, connect the autopilot board to 

your computer using the micro USB cable as shown below. Use a direct USB port on your 

computer (not a USB hub).
Pixhawk USB Connection

APM USB Connection

PX4 USB Connection

Windows should automatically detect and install the correct driver software. 

Connect to Mission Planner

Open the Mission Planner and select the COM port drop-down on the upper-right corner of the 

screen (near the Connect button). Select AUTO or the specific port for your board (PX4 FMU

or Arduino Mega 2560). Set the Baud rate to 115200 as shown. Don’t hit Connect just yet.
Install firmware

On the Mission Planner’s Initial Setup | Install Firmware screen select the appropriate icon 

that matches your frame (i.e. Quad, Hexa). Answer Yes when it asks you “Are you sure?”.

Mission Planner: Install Firmware Screen

After the Mission Planner detects which board you are using (i.e. Pixhawk) it will ask you to 

unplug the board, plug it back in and then press OK within a few seconds (during this brief 

period the bootloader accepts requests to upload new firmware).
Mission Planner: Install Firmware Prompt

If all goes well you will see some status appear on the bottom right including the words, 

“erase...”, “program...”, “verify..” and “Upload Done”. The firmware has been succesfully 

uploaded to the board.

Testing

You can test the firmware is basically working by switching to the Mission Planner Flight Data

screen and pressing the Connect button. The HUD should update as you tilt the board. 

Connect Mission Planner to AutoPilot has more information on connecting to Mission Planner.
Copter > common-Connect Mission Planner to AutoPilot

Connect Mission Planner to AutoPilot

This article explains how to connect Mission Planner to an autopilot in order to receive telemetry 

and control the vehicle.

Note:

There are separate instructions for connecting in order to Load Firmware.

Contents [hide]

 1 Setting up the connection

 2 Troubleshooting

 3 Related topics

Setting up the connection

To establish a connection you must first choose the communication method/channel you want to

use, and then set up the physical hardware and Windows device drivers. You can connect the PC 

and autopilot using USB cables, Telemetry Radios, Bluetooth, IP connections etc.

Note:

The driver for your connection hardware must be present on Windows as this makes your connection’s 

COM port and default data rate available to Mission Planner.

Pixhawk USB Connection

Connection using SiK Radio from 3DR
On Mission Planner, the connection and data rate are set up using the drop down boxes in the 

upper right portion of the screen. 

Once you’ve attached the USB or Telemetry Radio, Windows will automatically assign your 

autopilot a COM port number, and that will show in the drop-down menu (the actual number 

does not matter). The appropriate data rate for the connection is also set (typically the USB 

connection data rate is 11520 and the radio connection rate is 57600).

Select the desired port and data rate and then press the Connect button to connect to the 

autopilot. After connecting Mission Planner will download parameters from the autopilot and 

the button will change to Disconnect as shown:

Tip:

The “select port” dropdown also contains TCP or UDP port options that can be used to connect to an 

autopilot over a network.

Troubleshooting

If Mission planner is unable to connect:

 Check that the correct baud rate is used for the selected method (115200 on USB or 57600 on 

Radio/Telemetry)

 If using a COM port on Windows, check that the connection’s COM port exists in the Windows Device 

Manager’s list of serial ports.

 If using a USB port, try a different physical USB port

 if using a UDP or TCP connection, check that your firewall is not blocking the IP traffic. 

You should also ensure that the autopilot controller board has appropriate ArduPilot firwmare 

installed and has booted correctly (on Pixhawk/PX4 there are useful LEDs and Sounds which 

can tell you the state of the autopilot).
Related topics

Mission Planner Bluetooth Connectivity

Copter > Frame Type Configuration in Mission Planner

Frame Type Configuration in Mission 

Planner

On the Mission Planner‘s Initial Setup screen select Mandatory Hardware | Frame Type. 

Select the frame for your copter. The default configuration is X. If you want one of the arms to 

serve as the exclusive front-facing direction, select the Plus configuration. For Tricopters, 

Traditional Helis and Y6s, the frame type is ignored.

Mission Planner: Select Frame Type

Note:

For an H-Frame quadcopter use the option to set the frame type to ‘3’ in the Advanced Parameter Tab. 

To apply the H-frame configuration, swap the left rear and right rear props and reverse the motor 
direction for each of those motors (by swapping any two motor wires). Repeat the same process for the 

front two motors.

Copter > common-Compass Calibration in Mission Planner

Compass Calibration in Mission 

Planner

This article explains how to perform basic compass calibration.

Note:

This article assumes that you’re the most common configuration — a Pixhawk, PX4 or APM2.6 board 

with the compass mounted with the the arrow facing toward the front of the vehicle and in the same 

direction as the arrow on the autopilot. If you’re using a different configuration see Advanced Compass 

Setup.

Contents [hide]

 1 Calibration steps

 2 Additional information

 3 Video demonstration

Calibration steps

1. Under Initial Setup | Mandatory Hardware select Compass.

2. Select your autopilot configuration to automatically enter the most important configuration 

information for your board: 

 For Pixhawk and PX4, select the button Pixhawk/PX4.

 For APM 2.6, select APM with External Compass. 
Mission Planner: Compass Calibration

You shouldn’t need to do any more configuration, but you might want to confirm that 

the Enable compasses, Obtain declination automatically and Automatically learn offsets

check boxes are checked.

3. Click the Live Calibration button. 

A window should pop-up showing you the state of the live calibration.
Mission Planner: Live Compass Calibration

4. Hold the vehicle in the air and rotate it slowly so that each side (front, back, left, right, top and 

bottom) points down towards the earth for a few seconds in turn.

Compass Calibration Positions (shown for Copter, but true for all vehicles)

5. The calibration will automatically complete when it has data for all the positions. At this point, 

another window will pop up telling you that it is saving the newly calculated offsets. These are 

displayed on the main screen below each associated compass. 

Note:

In Copter-3.2.1 and later offsets are considered acceptable provided their combined “length” is less 

than 600 (i.e. sqrt(offset_x^2+offset_y^2+offset_Z^2) < 600). Prior to Copter 3.2.1 the 

recommendation was that the absolute value of each offset be less than 150 (i.e. -150 < offset < 

150).

Additional information

More information about compass configuration can be found in Advanced Compass Setup. This 

includes instructions for how to set up additional compasses, non-standard compass alignments,

compassmot, etc.
General discussion on magnetic interference and ways to reduce it can be found in Magnetic 

Interference

Copter > common-Radio Control Calibration in Mission Planner

Radio Control Calibration in Mission 

Planner

This article shows how to perform radio control calibration using Mission Planner.

Contents [hide]

 1 Overview

 1.1 Transmitter configuration

 1.2 Channel mappings

 2 Preconditions

 2.1 Safety first

 2.2 Centre trims

 2.3 Connect autopilot and turn on receiver

 3 Calibration steps

Overview

RC transmitters are used to control vehicle movement and orientation. Copter and Plane 

minimally control throttle, pitch, roll and yaw, while on Rover we just control throttle and roll. 

Each of these control signals are mapped to transmitter stick/switch(s) and in turn to autopilot 

channels from the connected receiver.

Calibrating each of the transmitter controls/channels is a straightforward process – simply move 

each of the enabled sticks/switches through their full range and record the maximum and 

minimum positions.

Transmitter configuration

There are two main transmitter configurations:
 Mode 1: left stick controls pitch and yaw, the right stick will control throttle and roll.

 Mode 2: left stick controls throttle and yaw; the right stick will control pitch and roll.

Transmitter (Mode 1): Recommended Channels Transmitter (Mode 2): Recommended Channels

Channel mappings

Copter:

Copter default channel mappings are:

 Channel 1: Roll

 Channel 2: Pitch

 Channel 3: Throttle

 Channel 4: Yaw

 Channel 5: Flight modes

 Channel 6: (Optional) Inflight tuning or camera mount (mapped to transmitter tuning knob)

Unused channels can be mapped to control additional peripherals.

Note:

 The default channel mappings can be changed using the instructions in RCMAP Input Channel 

Mapping. 
 Once you’ve calibrated the flight mode you can use the instructions in RC Transmitter Flight Mode 

Configuration to specify which vehicle modes are enabled by each switch position.

Preconditions

Safety first

For safety reasons you should disconnect the battery and/or remove propellers before preforming 

radio calibration.

Centre trims

Centre trims in manual RC mode before preforming RC calibration. If trims are not centred you 

may need to do the RC calibration again after you have used the vehicle (this is easy to do at the 

field).

Note:

Trims are centred when a moving vehicle does not change direction/speed/orientation when travelling 

hands-off with all controls/sticks in neutral positions. If there is any deviation in direction, speed or 

orientation, adjust the associated servo to compensate. 

Connect autopilot and turn on receiver

Connect the autopilot via USB and turn on your RC transmitter. Verify that the transmitter is 

bound to the receiver (the receiver displays a solid green light) and that it is set to use the correct 

model for your vehicle.

Open Mission Planner’s INITIAL SETUP | Mandatory Hardware | Radio Calibration

screen. If your RC receiver (Rx) and transmitter (Tx) are bound, you should see the green bars 

move when you move the transmitter sticks.
Mission Planner: Radio Calibration Screen (Copter)

Tip:

If the bars are not moving then check what LED lights the receiver is displaying:

 no lights – may indicate that it is incorrectly wired to the autopilot (look for connectors that may 

have been inserted upside down).

 red or a flashing green light – may indicate that your RC transmitter/receiver need be bound (see the 

manual that came with your RC equipment for instructions).

 a solid green light – recheck the autopilot is connected to the Mission Planner and if the bars are still 

not moving, try clicking on the Calibrate Radio button.

Calibration steps

1. Open Mission Planner’s INITIAL SETUP | Mandatory Hardware | Radio Calibration screen.

2. Click on the green Calibrate Radio button in the lower right of the window.

Mission Planner will display a prompt to check radio control equipment is on, battery is not

connected, and propellers are not attached. Select OK.
Mission Planner: Select Calibrate Radio and OK to begin calibrating.

3. Move the control sticks and toggle switches on your transmitter to their limits of travel and observe 

the results on the radio calibration bars. Red lines will appear across the calibration bars to indicate 

maximum and minimum values:

Mission Planner: Input range marked with red lines

Tip:

The green bars should move in the same direction as the transmitter sticks (except for Pitch where 

the bars move opposite to stick movements – low values are forward, high values are back). If the 

green bars move in the wrong direction, reverse them using your RC transmitter’s channel-reverse 

function (see your RC gear’s manual for guidance).
You should also calibrate the channel you have selected for controlling vehicle mode, and any 

other channels you have connected to the autopilot. 

4. Select Click when Done when all required channels are set at the minimum and maximum positions. 

Mission Planner will show a summary of the calibration data. Normal values are around 1100 

for minimums and 1900 for maximums.

Mission Planner: Radio 

Calibration Results

5. Turn off your transmitter and disconnect the battery if it was connected.
Copter > common-Accelerometer Calibration in Mission Planner

Accelerometer Calibration in Mission 

Planner

This article shows how to perform basic accelerometer calibration (using Mission Planner).

Note:

Accelerometer calibration is mandatory if you’re using EKF to estimate vehicle position.

Contents

 1 Calibration steps

 2 Video demonstration (Copter)

Calibration steps

1. Under Initial Setup | Mandatory Hardware, select Accel Calibration from the left-side menu.

Mission Planner: Calibrate Acceleration

2. Click Calibrate Accel to start the calibration. 

Mission Planner will prompt you to place the vehicle each calibration position. Press any key 

to indicate that the autopilot is in position and then proceed to the next orientation.
The calibration positions are: level, on right side, left side, nose down, nose up and on its 

back.

Accelerometer Calibration Positions (Copter)

Tip:

 It is important that the vehicle is kept still immediately after pressing the key for each step.

 You may need to calibrate the board before it is mounted if the size/shape of the vehicle makes 

this difficult.

 The level position is the most important to get right as this will be the attitude that your 

controller considers level while flying.

3. Proceed through the required positions (it is not necessary to use the Click When Done button).

Mission Planner: Accel Calibration – press any key

4. When you’ve completed the calibration process, Mission Planner will display “Calibration 

Successful!” as shown below.
Mission Planner: Calibration Successful

Warning:

Do not perform the press the Calibrate Level button. This function will overwrite your calibration values.
Copter > common-RC Transmitter Flight Mode Configuration

RC Transmitter Flight Mode 

Configuration

This article shows how you can enable up to 6 autopilot control/flight modes to be set from your 

RC transmitter.

Contents [hide]

 1 Flight modes configuration

 2 Setting the flight mode channel

 3 Transmitter configuration

 3.1 Test transmitter switch settings

 3.2 Tutorials for specific RC hardware

 3.3 Spektrum DX8 (alternate method)

Flight modes configuration

The mapping between switch position and flight mode is set in the Mission Planner Flight Mode

screen.

Copter:

Mission Planner: Flight Mode Screen (Copter).
You can set up the flight modes available on the transmitter by doing the following:

 Turn on your RC transmitter

 Connect the Pixhawk (or other flight controller) to the Mission Planner

 Go to the Initial Setup | Mandatory Hardware | Flight Modes screen

Note:

As you move your transmitter’s flight mode switch the green highlight bar will move to a different 

position.

 Use the drop-down on each line to select the flight mode for that switch position.

 (Copter) Ensure that at least one switch position is left assigned to STABILISE.

 (Copter) Optionally check the Simple Mode check-box for that switch position. If using AC3.1 or 

higher you can optionally set Super Simple mode. If both Simple mode and Super Simple mode 

checkboxes are checked Super Simple will be used.

 When finished press the Save Modes button.

(Copter) Some modes can also be invoked from the auxiliary switches (a.k.a. ch7, ch8 option 

switches). For example, to set a dedicated switch for RTL.

Setting the flight mode channel

The flight mode channel is the input radio channel that ArduPilot monitors for mode changes.

On Copter this is always channel 5. 

Transmitter configuration
The transmitter must emit PWM signals in the correct range to allow us to map a mode to a 

switch position.

Note:

The correct PWM ranges for selectable modes are shown alongside each mode selection dropdown in 

the Mission Planner Flight Mode screen (see screenshot above). 

If you want to just support three modes (using a three position switch) then you would configure 

the transmitter to produce PWM pulse widths of 1165, 1425, and 1815 microseconds for the 

respective switch positions.

If you want to support 6 modes then the transmitter will need to emit PWM widths of around 

1165, 1295, 1425, 1555, 1685, and 1815 milliseconds. Typically this is achieved by configuring 

the transmitter to mix a two position switch and a three position switch (giving 6 modes in total). 

You can also do this with an analog dial if one is available, but it’s hard to reliably turn a dial to 

just the right position for six distinct settings.

The sections below provide links showing how to configure transmitters from different 

manufactures, and how to test (in Mission Planner) that each switch setting is emitting the 

appropriate PWM signal.

Test transmitter switch settings

You can use the Mission Planner Radio Calibration screen to test the PWM pulse widths for 

each mode setting.

Simply toggle through the modes on your transmitter and confirm that the PWM for the selected 

channel matches the required PWM values. The screenshot below assumes that the flight mode 

channel is set to Radio 5.
Tutorials for specific RC hardware

Here are some user-contributed tutorials for doing this (or adding more modes to RC units with 

just a two-position toggle) with various RC systems:

 JR XG8 DMSS

 JR9303

 JR X2720

 Futaba T8FG

 Futaba T8J

 Futaba T7CP

 Futaba T6EX

 Futaba 12fg

 Futaba 9ZAP/ZHP

 Futaba T10CAG

 Futaba T14

 Futaba 9C Super

 Graupner MX-16

 Turnigy 9x(or an even easier way) (Here!)

 Turnigy 9x with ER9x firmware

 Turnigy 9XR

 Hitech Aurora 9

 Spektrum DX8 (alternate method below)

 Spektrum DX7

 Spektrum DX7s
 Spektrum DX7 Version 6

Or build your own six-position switch!

Spektrum DX8 (alternate method)

This section describes an alternative way to set 6 modes with the Spektrum DX8. This method 

uses the Gear switch and the Flight mode switch. All the other switches can be assigned as 

preferred. This method also allows each mode to be set in the middle of each mode’s pulse width 

range so small changes will not change modes. Use Mission Planner Flight Modes setup to 

monitor the Current PWM for these adjustments.

1. Setup the switches (*required for the 6 modes) 

 Hold roller bar down, turn on DX8, scroll down to Switch Select, Click roller bar. Set switches as 

follows:

 * Gear = Gear (Channel 5)

 * FMode = Inh Not assigned to a channel – Used to mix with Gear Sw (Channel 5) for 6 modes

 Others anyway you want. One method is as follows: 

 Knob to aux1 = channel 6 for camera tilt / tuning

 Mix = aux2 = channel 7 to save Way Point or RTL, auto trim or other settings in APM 

configuration.

 Flap to aux3 = channel 8 for other uses

 Click BACK until the normal screen appears, or turn off power, then turn power back on.

2. Set up the non-mixed servo setting for channel 5 (Gear channel controlled by the Gear Switch)

This will be the values with no mixing – F Mode switch in the 0 position and sets the lowest pulse 

width to 1165 ms (mode 1) and highest to 1815 ms (mode 6)

 Click the roller bar, scroll down to Servo Setup, Select the Gear channel, Select Sub Trim.

 Set sub trim to 0

 Select Travel.

 Set travel (left, position 0) for 1165 ms pulse (~90%).

 Set travel (right, position 1 for 1815 ms pulse (~74%).

 Set up Mix 1 to change the Gear Pulse width when F Mode is in position 1 

 Click roller, scroll down to Mixing, click roller, scroll to first line under Mix (has xxx > xxx, AIL > 

RUD, or some other mix set),click roller, Select Mix 1, Click roller.

 Set Mix: Gear > Gear. Gear changes Gear depending on Switch F Mode setting

 Set Offset = 0, Trim = Inh.

 Set SW = FM 1

 Set the F Mode switch on the transmitter to position 1.

 Set the Gear switch on the transmitter to position 0.

 Set top Rate for pulse width of 1290 ms for mode 2 (~-35%)

(change = 400 ms * -90% * -35% = 126 ms. Result = 1165 ms + 126 ms = 1251 ms = mode 2)

 Set the Gear switch on the transmitter to position 1.

 Set bottom Rate for pulse width of 1685 ms for mode 5 (~– 45%)

(change = 400 ms * +73% *- 45% = -131 ms. Result = 1815 ms – 131 ms = 1684 ms = mode 5)

 Set up a mix 2 to change the Gear Pulse width when F Mode is in position 2 
 Mix: Gear > Gear. Gear changes Gear depending on Switch F Mode setting.

 Set Offset = 0, Trim = Inh

 Set SW = FM2

 Set the F Mode switch on the transmitter to position 2

 Set the Gear switch on the transmitter to position 0.

 Rate top Rate for pulse width of 1425 ms for mode 3 (~–72%) (change = 400 ms * –90% * – 72% = 

259 ms. Result = 1165 ms + 259 ms = 1424 ms = mode 3)

 Set the Gear switch on the transmitter to position 1.

 Set bottom Rate for pulse width of 1550 ms for mode 4 (~–89%) (change = 400 ms * +73% * –

89% = -262 ms. Result = 1815 ms – 262 ms = 1553 ms = mode 4)

Copter > Electronic Speed Controller (ESC) Calibration

Electronic Speed Controller (ESC) 

Calibration

Electronic speed controllers are responsible for spinning the motors at the speed requested by the 

autopilot. Most ESCs need to be calibrated so that they know the minimum and maximum pwm 

values that the flight controller will send. This page provides instructions for calibrating ESCs. 

Note:

Please complete radio calibration before performing ESC calibration.

Contents [hide]

 1 About ESC Calibration

 2 All at once calibration

 3 Manual ESC-by-ESC Calibration

 3.1 Calibrating ESCs individually (Currently Untested on PX4)

 4 Testing

 5 Notes / Troubleshooting

About ESC Calibration

ESC calibration will vary based on what brand of ESC you are using, so always refer to the 

documentation for the brand of ESC you are using for specific information (such as tones). “All 
at once” calibration works well for most ESCs, so it is good idea to attempt it first and if that 

fails try the “Manual ESC-by-ESC” method.

 For 3DR ESCs can use the “All at once” method.

 DJI Opto ESCs do not require and do not support calibration, so skip this page completely

 Some brands of ESC do not allow calibration and will not arm unless you adjust your radio’s throttle 

end-points so that the minimum throttle is around 1000 PWM. Note that if you change the endpoints on your TX you must re-do the Radio Calibration.

 Begin this procedure only after you have completed the radio control calibration and Connect ESCs 

and motors part of the Assembly Instructions. Next follow these steps:

All at once calibration

Warning:

Safety Check!

Before calibrating ESCs, please ensure that your copter has NO PROPS on it and that the APM is NOT 

CONNECTED to your computer via USB and the Lipo battery is disconnected.

1. Turn on your transmitter and put the throttle stick at maximum.
2. Connect the Lipo battery. The autopilot’s red, blue and yellow LEDs will light up in a cyclical 

pattern. This means the it’s ready to go into ESC calibration mode the next time you plug it in.

3. With the transmitter throttle stick still high, disconnect and reconnect the battery.

4. For PX4 or Pixhawk, press and hold the safety button until it displays solid red.

5. The autopilot is now in ESC calibration mode. (On an APM you may notice the red and blue LEDs 

blinking alternatively on and off like a police car).

6. Wait for your ESCs to emit the musical tone, the regular number of beeps indicating your battery’s 

cell count (i.e. 3 for 3S, 4 for 4S) and then an additional two beeps to indicate that the maximum 

throttle has been captured.

7. Pull the transmitter’s throttle stick down to its minimum position.

8. The ESCs should then emit a long tone indicating that the minimum throttle has been captured and 

the calibration is complete.

9. If the long tone indicating successful calibration was heard, the ESCs are “live” now and if you raise 

the throttle a bit they should spin. Test that the motors spin by raising the throttle a bit and then 

lowering it again.

10. Set the throttle to minimum and disconnect the battery to exit ESC-calibration mode
Copter > Flight Modes

Flight Modes

This article provides an overview of the available flight modes for Copter and instructions for 

how to configure which modes are available through the RC Transmitter.

Contents [hide]

 1 Overview

 2 Recommended Flight Modes

 3 GPS Dependency

Overview

Copter has 14 flight built-in flight modes, 10 of which are regularly used. There are modes to 

support different levels/types of flight stabilization, a sophisticated autopilot, a follow-me system 

etc. 

Flight modes are controlled through the radio (via a transmitter switch), via mission commands, 

or using commands from a ground station (GCS) or companion computer.

Recommended Flight Modes

In general when first starting to use Copter you should progress through the flight modes in the 

order listed below, being sure that you are comfortable with each before progressing to the next 

(click the links for more details):

 Stabilize

 Alt Hold

 Loiter

 RTL (Return-to-Launch)

 Auto

Additional flight modes:

 Acro

 Sport

 Drift
 Guided

 Circle

 PosHold

 Land

 Brake

 Follow Me

 Simple and Super Simple 

Most transmitters provide a 3 position switch but you can find instructions here for setting up a 

6-position flight mode switch.

GPS Dependency

Flight modes that use GPS-positioning data require an active GPS lock prior to takeoff. To see if 

your autopilot has acquired GPS lock, connect to a ground station or consult your autopilot’s 

hardware overview page to see the LED indication for GPS lock. Below is a summary of GPS 

dependency for Copter flight modes.

Requires GPS lock prior to takeoff:

 Loiter

 RTL (Return-to-Launch)

 Auto

 Guided

 Drift

 PosHold

 Follow Me

 Circle

Do not require GPS lock:

 Stabilize

 Alt Hold

 Acro

 Sport

 Land
Copter > Pre-Arm Safety Check

Pre-Arm Safety Check

Copter includes a suite of Pre-arm Safety Checks which will prevent the vehicle from arming if 

any of a fairly large number of issues are discovered before take-off including missed 

calibration, configuration or bad sensor data. These checks help prevent crashes and fly-aways 

but they can also be disabled if necessary.

Contents [hide]

 1 Recognising which Pre-Arm Check has failed using the GCS

 2 Failure messages

 3 Disabling the Pre-arm Safety Check

Recognising which Pre-Arm Check has failed using the 

GCS

The pilot will notice a pre-arm check failure because he/she will be unable to arm the copter and 

the LED will be flashing yellow. To determine exactly which check has failed:

1. Connect the Flight Controller to the ground station using a USB cable or Telemetry.

2. Ensure the GCS is connected to the vehicle (i.e. on Mission Plannerand push the “Connect” button on 

the upper right).

3. Turn on your radio transmitter and attempt to arm the vehicle (regular procedure using throttle 

down, yaw right)

4. The first cause of the Pre-Arm Check failure will be displayed in red on the HUD window

Failure messages

RC failures (i.e. transmitter/receiver failures):

RC not calibrated : the radio calibration has not been performed. RC3_MIN and RC3_MAX 

must have been changed from their default values (1100 and 1900) and for channels 1 to 4, the 

MIN must be less than 1300 and the MAX greater than 1700.

Barometer failures:

Baro not healthy : the barometer sensor is reporting that it is unhealthy which is normally a sign 

of a hardware failure.
Alt disparity : the barometer altitude disagrees with the inertial navigation (i.e. Baro + 

Accelerometer) altitude estimate by more than 2 meters. This message is normally short-lived 

and can occur when the flight controller is first plugged in or if it receives a hard jolt (i.e. 

dropped suddenly). If it does not clear the accelerometers may need to be calibrated or there 

may be a barometer hardware issue.

Compass failures:

Compass not healthy : the compass sensor is reporting that it is unhealthy which is a sign of a 

hardware failure.

Compass not calibrated : the compass(es) has not been calibrated. the COMPASS_OFS_X, Y, 

Z parameters are zero or the number or type of compasses connected has been changed since the 

last compass calibration was performed.

Compass offsets too high : the primary compass’s offsets length (i.e. sqrt(x^2+y^2+z^2)) are 

larger than 500. This can be caused by metal objects being placed too close to the compass. If 

only an internal compass is being used (not recommended), it may simply be the metal in the 

board that is causing the large offsets and this may not actually be a problem in which case you 

may wish to disable the compass check.

Check mag field : the sensed magnetic field in the area is 35% higher or lower than the 

expected value. The expected length is 530 so it’s > 874 or < 185. Magnetic field strength 

varies around the world but these wide limits mean it’s more likely the compass calibration has 

not calculated good offsets and should be repeated.

Compasses inconsistent : the internal and external compasses are pointing in different directions 

(off by >45 degrees). This is normally caused by the external compasses orientation (i.e. 

COMPASS_ORIENT parameter) being set incorrectly.

GPS related failures:

GPS Glitch : the GPS is glitching and the vehicle is in a flight mode that requires GPS (i.e. 

Loiter, PosHold, etc) and/or the circular fence is enabled.

Need 3D Fix : the GPS does not have a 3D fix and the vehicle is in a flight mode that requires 

the GPS and/or the circular fence is enabled.

Bad Velocity : the vehicle’s velocity (according to inertial navigation system) is above 

50cm/s. Issues that could lead to this include the vehicle actually moving or being dropped, bad 

accelerometer calibration, GPS updating at below the expected 5hz.
High GPS HDOP : the GPS’s HDOP value (a measure of the position accuracy) is above 2.0 

and the vehicle is in a flight mode that requires GPS and/or the circular fence is enabled. This 

may be resolved by simply waiting a few minutes, moving to a location with a better view of the 

sky or checking sources of GPS interference (i.e. FPV equipment) are moved further from the 

GPS. Alternatively the check can be relaxed by increasing the GPS_HDOP_GOOD parameter to 

2.2 or 2.5. Worst case the pilot may disable the fence and take-off in a mode that does not 

require the GPS (i.e. Stabilize, AltHold) and switch into Loiter after arming but this is not 

recommended.

Note: the GPS HDOP can be readily viewed through the Mission Planner’s Quick tab as shown 

below.

INS checks (i.e. Acclerometer and Gyro checks):

INS not calibrated: some or all of the accelerometer’s offsets are zero. The accelerometers 

need to be calibrated.

Accels not healthy: one of the accelerometers is reporting it is not healthy which could be a 

hardware issue. This can also occur immediately after a firmware update before the board has 

been restarted.
Accels inconsistent: the accelerometers are reporting accelerations which are different by at 

least 1m/s/s. The accelerometers need to be re-calibrated or there is a hardware issue.

Gyros not healthy: one of the gyroscopes is reporting it is unhealthy which is likely a hardware 

issue. This can also occur immediately after a firmware update before the board has been 

restarted.

Gyro cal failed: the gyro calibration failed to capture offsets. This is most often caused by the 

vehicle being moved during the gyro calibration (when red and blue lights are flashing) in which 

case unplugging the battery and plugging it in again while being careful not to jostle the vehicle 

will likely resolve the issue. Sensors hardware failures (i.e. spikes) can also cause this failure.

Gyros inconsistent: two gyroscopes are reporting vehicle rotation rates that differ by more than 

20deg/sec. This is likely a hardware failure or caused by a bad gyro calibration.

Board Voltage checks:

Check Board Voltage: the board’s internal voltage is below 4.3 Volts or above 5.8 Volts.

If powered through a USB cable (i.e. while on the bench) this can be caused by the desktop 

computer being unable to provide sufficient current to the flight controller – try replacing the 

USB cable.

If powered from a battery this is a serious problem and the power system (i.e. Power Module, 

battery, etc) should be carefully checked before flying.

Parameter checks:

Ch7&Ch8 Opt cannot be same: Auxiliary Function Switches are set to the same option which 

is not permitted because it could lead to confusion.

Check FS_THR_VALUE: the radio failsafe pwm value has been set too close to the throttle 

channels (i.e. ch3) minimum.

Check ANGLE_MAX: the ANGLE_MAX parameter which controls the vehicle’s maximum 

lean angle has been set below 10 degrees (i.e. 1000) or above 80 degrees (i.e. 8000).

ACRO_BAL_ROLL/PITCH: the ACRO_BAL_ROLL parameter is higher than the Stabilize 

Roll P and/or ACRO_BAL_PITCH parameter is higher than the Stabilize Pitch P value. This 

could lead to the pilot being unable to control the lean angle in ACRO mode because the Acro 

Trainer stabilization would overpower the pilot’s input.
Disabling the Pre-arm Safety Check

If you are confident that the pre-arm check failure is not a real problem you can disable the 

checks by:

 Connecting your Flight Controller to the Mission Planner

 Go to Mission Planner’s Config/Tuning >> Standard Params screen

 set the Arming Check drop-down to “Disabled” or one of the “Skip” options which more effectively 

skips the item causing the failure.

 Push the “Write Params” button

Ideally however you should determine the cause of the pre-arm failure and if it can be resolved, 

return the Arming Check parameter back to “Enabled”

Copter > Arming the motors

Arming the motors

Contents [hide]

 1 Arming the motors

 2 Disarming the motors
Arming the motors

Before arming the motors, make sure all people and objects are clear of the propellers. Then do 

the following:

1. Turn on your transmitter

2. Plug in your LiPo battery. The red and blue lights should flash for a few seconds as the gyros are 

calibrated (do not move the copter)

3. The pre-arm checks will run automatically and if any problems are found an APM2.x will double blink 

the red arming light, on a Pixhawk the RGB led will blink yellow. Please refer to this page.

4. Check that your flight mode switch is set to Stabilize, ACRO, AltHold or Loiter.

5. If using a PX4, press the safety button until the light goes solid.

6. If you are planning on using the autopilot (i.e. Loiter, RTL, Drift, Auto or Guided modes) you should 

wait for 30 seconds after the GPS has gotten 3d lock. This will give the GPS position time to 

settle. On APM2 the GPS lock is indicated by the blue LED going solid. On an Pixhawk the RGB LED 

will blink green.

7. Arm the motors by holding the throttle down, and rudder right for 5 seconds. It takes approximately 

5 seconds the first time the copter is armed as it re-initialises the gyros and barometer. Do not hold 

the rudder right for too long (>15 seconds) or you will begin the AutoTrim feature.

8. Once armed, the red arming light should go solid and the propellers will begin to spin slowly. The 

speed they spin can be adjusted with the MOT_SPIN_ARMED parameter.

9. Raise the throttle to take-off.

Note:

You can only arm or disarm in Stabilize, ACRO, AltHold and Loiter mode.

Note:

If you leave the throttle at minimum for 15 seconds while in any of the above modes the motors will 

automatically disarm.

Disarming the motors

To disarm the motors do the following:

1. Check that your flight mode switch is set to Stabilize, ACRO, AltHold or Loiter

2. Hold throttle at minimum and rudder to the left for 2 seconds

3. The red arming light should start flashing on the APM2. On the Pixhawk the RGB LED will start 

flashing green.

4. If using a PX4, press the safety button until the led begins flashing

5. Disconnect the Lipo battery

6. Turn off your transmitter
Copter > Failsafe

Failsafe

Copter has a number of failsafe mechanisms to ease vehicle recovery/prevent wandering in the 

event that vehicle control is lost. The main failsafe topics are listed below.

 Radio Failsafe

 Battery Failsafe

 GCS Failsafe

 EKF / DCM failsafe

 Simple GeoFence

Copter > Pre-Flight Checklist (Copter)

Pre-Flight Checklist (Copter)

This page is provides a list of things to check following configuration, and before your first 

flight. 

Contents [hide]

 1 Summary Checklist

 2 Configuration

 3 Flying

Summary Checklist

Configuration

 Spin up the propellers on the ground and check they are all moving in the correct orientation.

 Check that your copter knows what level is. With the copter on a flat surface connect to Mission 

Planner and ensure the artificial horizon display shows level.

 Check all failsafe settings are enabled. Instructions are here for radio, battery, gcs and ekf/gps. 

Flying

 Make sure you have a GPS lock before flying if you intend to use any auto modes. Even if you’re only 

flying in Stabilized mode this is a good idea so you can invoke Return To Launch if you get into 

trouble.

 Test RTL before sending your copter off on an auto waypoint flight. This is to check that the compass 

and GPS are working, and that it knows where home is before heading off on a more complex flight.

 Ensure that flight in Stabilize works well before you attempt any more complex flight modes. Ensure 

loiter works before trying RTL. Ensure RTL works before trying auto.

 Once armed stand 3m-6m away from the arming point as when in RTL the copter will be returning to 

this point.

 When testing more complex flight modes, be ready to switch back to Stabilize mode at any moment 

if it does anything strange. Stabilize or Acro are the only modes which can save you from a problem 

with the software or sensors. RTL is a good mode to save you from human error, but relies on the 

copter being able to locate and fly itself, so this should not be used as an emergency mode if other 

auto flight modes go wrong.

 Be sure you have a way of knowing when your battery is getting low, and land before you have used 

more than 80% of your battery capacity.

Copter > common-Mission Planning

Mission Planning

This section contains articles about Mission Planning; creating automated missions that will run 

when the ArduPilot is set to AUTO mode. 

 Planning a Mission with Waypoints and Events

 Copter Mission Command List

 Mission Command List

 Camera Control and Auto Missions in Mission Planner

 Rally Points

 Terrain Following
 Geotagging Images

Note:

The examples demonstrate mission planning using Mission Planner, a fully-functioned Windows-based 

Ground Control Station (GCS) that you can download and install from here.

Mission Planner: Flight Plan Screen

The main concepts will also apply to other Ground Control Stations (although the details of the 

user interface will differ).