MeekPE PPM Encoder Board

MeekPE is a low cost MCUless PPM Encoder.
This small board encodes and combines the separate PWM servo signals output from the R/C receiver without using a microcontroller. The combined signal is input into the PPM input on the Paparazzi controller.
Using common, inexpensive, components this board is a simple, affordable way to connect almost any type of R/C receiver to the Autopilot without modifications.
== Hardware Revision History ==
Version # 	Release Date	Release Notes
v1.00 (current)	08/2010 	0603/TSSOP PCB design
v0.10 	08/2010 	0805/SOIC Single layer test PCB design
v0.00 	07/2010 	Ugly Prototype
== Features ==
:* no hardware modification of the R/C receiver
:* no MCU => no software or firmware req.
:* up to 8 servo encoding inputs
:* 25.4 x 15.6mm (1.0 x 0.6")
:* ..g (..oz)
:* inexpensive
:* works with most types of receivers (has been tested with Spektrum for example)
==== Restrictions: ====
:* see Connection instructions below
== Block Diagram ==
== Overview ==
Image:MeekPE v0-00 ugly test.jpg|First ugly test (this is not a joke)
Image:MeekPE v0-10 proto.jpg|Test board 0805/SOIC components
File:MeekPE01.jpg|Assembled board
== Pinout ==
RECEIVER
Pin # 	Name 	Type	Description 	Suggested Color
1 	GND 	PWR 	Common ground 	Black
2 	+5V 	PWR 	5V to R/C receiver supply(optional, see connection instructions below) 	Red or Orange
3 to 9	SERVO 	IN 	From R/C receiver servo output(see connection instructions below) 	Yellow
10 	LAST SERVO	IN 	From R/C receiver servo output. Last channel to be encoded(see connection instructions below)	White
AUTOPILOT
Pin #	Name	Type	Description 	Suggested Color
1 	GND 	PWR 	Common ground 	Black
2 	+5V 	PWR 	5V rail from autopilot(see connection instructions below)	Red or Orange
3 	PPM 	OUT 	Positive logic PPM output 	Blue
== Connections ==
=== MeekPE to Autopilot ===
:* Ground, Power ("+5V") and PPM signal must be connected to the autopilot.
:* Power ("+5V") pin is used to supply the MeekPE board (+3.5V to +16V or C9 rated voltage if below, see Note1) and can also supply your receiver. In this case, MeekPE supply voltage must match your R/C receiver power supply voltage (around +5V in general).
:* You can use a classic Molex 3 pin connector or solder wires directly on board: 3 additional bigger thru-hole pads are provided for this purpose.
=== R/C receiver to MeekPE ===
You can use:
:* classic 0.1" pitch break away header and female/female jumper wires (like SparkFun's PRT-08430)
:* cut in half SparkFun's PRT-08430 female/female jumper wires and solder it directly to the MeekPe.
==== Powering the R/C receiver ====
:* Ground connection is mandatory (voltage reference between the R/C receiver and the MeekPE encoder)
:* Power output pin ("+5V") is used only if you decide to supply your receiver with the autopilot. In this case, MeekPE supply voltage from the A/P must match your R/C receiver power supply voltage (around +5V in general)
==== Servo connections rules ====
To get a correct PPM encoded signal, you must follow some (simple) rules:
:* You must know the channel number of the first and the last servo signal you want to encode.
:* All servo connection between the first and last channel you want to encode must exist: on some (stupid?) R/C receiver there is a "hole" in available channels. For example, on Hitec HFS-05MS you can get only CH1, 2, 3, 4, and 6. Channel #5 doesn't exist (outside the receiver box...)
:* All servo connection between the first and last channel you want to encode must be connected, even if you don't use it in the autopilot code.
:* The last channel number servo signal you want to encode must be connected to the "LAST-SERVO" input pin of the MeekPE encoder. Other servos connections can be in any order because the channel encoding number is given by the transmitter, not by the MeekPE encoder.
=== Servo connection example ===
Ok, finally, servo connection rules are not so simple. So perhaps will it be better understandable with some examples.
:* 6 channel R/C receiver, you want to encode Throttle (channel#1), Pitch (channel#2), Roll (channel#3), and Mode Switch (channel#5):
::=> connect #1, 2, 3, 4 receiver servo output to any MeekPE servo input and channel #5 on "LAST SERVO" MeekPE input. You can leave #6 unconnected.
:* 8 channel R/C receiver, you want to encode channel#2 to channel#5 and channel#7:
::=> connect #2, 3, 4, 5, 6 receiver servo output to any MeekPE servo input and channel #7 on "LAST SERVO" MeekPE input. You can leave #8 unconnected.
== Schematic ==
== PCB ==
Image:MeekPE_v1-00_top_copper.png|MeekPE v1.00 PCB top copper
Image:MeekPE_v1-00_bottom_copper.png|MeekPE v1.00 PCB bottom copper
=== Gerber & Drill Files ===
====Olimex Compliant Gerber Files====
Download MeekPE v1.00 gerber & drill files (zip)
Gerber RS274X format = 2:5, units = Inches
:*MeekPE_v1-00.GTO (Top Component Print Layer)
:*MeekPE_v1-00.GTS (Top Solder Mask)
:*MeekPE_v1-00.GTL (Top Copper Layer)
:*MeekPE_v1-00.GBL (Bottom Copper Layer)
:*MeekPE_v1-00.GBS (Bottom Solder Mask)
NC Drill format = 2:5, units = Inches
:*MeekPE_v1-00.DRI (NC XY coordinates & Drill tools sizes)
====BatchPCB Compliant Gerber Files====
Now you can buy the PCB directly for $2.50 here
Download BatchPCB Compliant MeekPE v1.00 gerber & drill files (zip)
Gerber RS274X format = 2:5, units = Inches
:*MeekPE_v1-00.GTO (Top Component Print Layer)
:*MeekPE_v1-00.GTS (Top Solder Mask)
:*MeekPE_v1-00.GTL (Top Copper Layer)
:*MeekPE_v1-00.GBL (Bottom Copper Layer)
:*MeekPE_v1-00.GBS (Bottom Solder Mask)
:*MeekPE_v1-00.GBO (Bottom Component Print Layer)
NC Drill format = 2:4, units = Inches
:*MeekPE_v1-00.DRL (NC XY coordinates & Drill tools sizes)
== Assembly ==
=== Components Layout ===
Image:MeekPE_2D_components_layout.png|MeekPE v1.00 Components Layout
Image:MeekPE_components_layout.png|MeekPE v1.00 Components Details
=== Bill Of Material ===
Qty 	Manufacturer part #	Schematic part name / value	Designator 	Description 	Manufacturer 	Package 	Optional 	Digikey.com 	Other distributor
Resistors 	Resistors 	Resistors 	Resistors 	Resistors 	Resistors 	Resistors 	Resistors 	Resistors 	Resistors
9 	RMCF0603FT10K0 	10K 	R1-R8,R11 	1/10W 1% 	Stackpole 	0603 	 	RMCF0603FT10K0CT-ND	
2 	RMCF0603FT100K 	100K 	R9,R10 	1/10W 1% 	Stackpole 	0603 	 	RMCF0603FT100KCT-ND	
Capacitors 	Capacitors 	Capacitors 	Capacitors 	Capacitors 	Capacitors 	Capacitors 	Capacitors 	Capacitors 	Capacitors
9 	CC0603KRX7R8BB103 	10nF 	C1-C8,C11 	25V X7R 	Yageo 	0603 	 	311-1360-1-ND 	
2 	JMK107BJ475KA-T 	4.7uF 	C9,C10 	6.3V X5R (see Note1) 	Taiyo Yuden 	0603 	 	587-1785-1-ND 	
Semiconductors	Semiconductors 	Semiconductors 	Semiconductors	Semiconductors 	Semiconductors 	Semiconductors 	Semiconductors	Semiconductors 	Semiconductors
10 	1PS79SB10 	1PS79SB10 	D1-D10 	Schottky diode 0.2A/30v 	NXP 	SOD523 (EIA SC79)	 	1PS79SB10,115-ND 	
1 	BC847B,215 	BC847 	T1 	NPN general purpose transistor 100mA/45V	NXP 	SOT23 	 	BC847B,215 	
1 	74HC14DTR2G 	74HC14PW 	IC1 	Hex Schmitt Trigger Inverter 	ON 	TSSOP14 	 	74HC14DTR2GOSCT-ND 	
1 	LP2985-33DBVR 	LP2985-33 	IC2 	3.3V/150mA LDO regulator 	Texas Instruments	SOT23-5 	 	296-18476-1-ND 	
Connectors 	Connectors 	Connectors 	Connectors 	Connectors 	Connectors 	Connectors 	Connectors 	Connectors 	Connectors
1 	53047-0310 	PPM 	J2 	Picoblade 3 pins 1.25mm straight header 	Molex 	specific 	yes 	WM1732-ND 	
10pins 	22-28-4363 	SRV 	J1 	0.1" Header 36Pos. Vertical Gold 	Molex 	specific 	yes 	WM6536-ND 	
:* Note1 : If below 16v, rated voltage of C9 will be the upper limit for MeekPE supply voltage.
== Source files ==
:*download MeekPE v1.00 Protel 99SE SP6 design (zipped Protel 99 ddb file)
Category:Hardware