How do I connect my circuit to an Arduino Uno? - Page 1
Forum section: electronics / beginners

author: astroasma
author_rank: Contributor
timestamp: July 30, 2022, 05:14:02 pm
content: Hello everyone,I am building a circuit for a heater using the following components:2x MOSFETs4x film resistors2x diodesCapacitorNichrome coil12V lithium batteryTemperature sensorFanAll of these components are connected by wires/solder.How do I connect all those to the Arduino Uno in order to control the circuit please? Should I use a breadboard?Thanks!

author: Ian.M
author_rank: Super Contributor
timestamp: July 30, 2022, 05:36:04 pm
content: Simply don't! Buy an Arduino Nano (which is 100% Uno software compatible), preferably without pre-fitted pin headers, so you can solder your wires direct to its I/O pads.However if you must, terminate your wires with male 'duPont' pins in multi-way 0.1" pitch single row shells, (beware of the off-pitch gap between D7 and D8) and simply plug them in to the Arduino headers, or buy an Arduino Uno footprint breakout shield and hook up your wires to that.

author: AndyBeez
author_rank: Frequent Contributor
timestamp: July 30, 2022, 05:46:48 pm
content: I suggest you start by considering the 48 volt UNO relay shield.https://docs.arduino.cc/tutorials/4-relays-shield/4-relay-shield-basics

author: tunk
author_rank: Super Contributor
timestamp: July 30, 2022, 06:00:08 pm
content: It may help if you post the schematics of the heater circuit.

author: rstofer
author_rank: Super Contributor
timestamp: July 30, 2022, 06:12:52 pm
content: If this is for educational demonstration, something like the Temperature Control Lab might be a better approach:http://apmonitor.com/pdc/index.php/Main/ArduinoTemperatureControlThe controller is just an Arduino shield but there is code to use the Arduino with MATLAB and that makes it very useful.

author: astroasma
author_rank: Contributor
timestamp: July 30, 2022, 06:46:13 pm
content: Here is the circuit

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2022, 06:48:42 pm
content: Why are you starting another thread? This is presumably your ISS heater project.You are clearly getting good responses on your other thread and from the above replies, you're obviously confusing people.https://www.eevblog.com/forum/projects/design-of-heater-circuit-using-resistors/msg4322665/#msg4322665Keep context or you just waste peoples' time.

author: tooki
author_rank: Super Contributor
timestamp: July 31, 2022, 01:07:22 pm
content: Quote from: astroasma on July 30, 2022, 06:46:13 pmI don’t think this can work.Is the circles thing on the right supposed to be the load? (Resistive heaters should be drawn as resistors. Or just draw outputs to the load. But don’t invent your own symbols, and don’t misuse the symbols for totally different components. It looks like you were trying to draw a coil, but in schematics, a coil is specifically used for an inductor.)Where are the control inputs to the MOSFETs? There’s nothing connected to the gates.Where’s the temperature sensor?Are you using a microcontroller after all?Is it your intent for this to be a positive-ground system? That is how it’s drawn, but at first glance, I don’t think it could work, and negative ground would complicate interfacing it to a microcontroller.

author: Ian.M
author_rank: Super Contributor
timestamp: July 31, 2022, 01:30:28 pm
content: Furthermore, *If* your gates were connected, the diodes would clamp the gate voltage as the MOSFETs turn on, keeping them in their linear region, and if they are inadequately heatsinked or not rated for DC linear operation, destroying the MOSFETs.

author: pcprogrammer
author_rank: Super Contributor
timestamp: July 31, 2022, 01:57:27 pm
content: Looked at her other posts and in one of them she refers to an induction heater, so I guess that is where the circle symbol comes from.This would mean a non DC control of the MOSFETS. but still the circuit looks odd, and like tooki wrote with the positive being ground hard to control from a MCU.From the other thread I understood that the system is intended for space heating a small box and then induction heating seems a bit odd, because for what I understand from this kind of induction heating it is intended to melt metals. The video she linked to in her post here:https://www.eevblog.com/forum/projects/design-of-heater-circuit-using-resistors/msg4327588/#msg4327588shows that it needs a piece of metal in the coil to generate heat.A far simpler solution is to use a proper heating element and control the current through it with a MOSFET. With pulse width modulation the amount of power can be controlled. Only needs a single MOSFET and a small gate resistor.Edit: Isn't the given schematic some kind of free running oscillator? That would explain the induction heater idea.Edit2: And guess where the schematic came from:On another not important note did anyone notice she might be French, or at least her computer is set to French. Look at the name of the picture: "Capture d’écran 2022-07-30 à 20.37.16"

author: Ian.M
author_rank: Super Contributor
timestamp: July 31, 2022, 02:17:49 pm
content: Thanks for spotting that - yes it does look like a Mazzilli ZVS resonant driver, if one takes the column of circles to be a center-tapped coil. However Mazzilli drivers are notorious for blowing MOSFETs due to linear region operation if their somewhat finicky startup conditions aren't met, or if run with an unsuitable load, or excessive or insufficient supply voltage.*IF* this is for the experiment heater in their other topic, the chances of it flying to orbit are zero as I don't see any way a basic Mazzilli driver could pass the design safety and EMC review process, due to the risk of interference with nearby avionics.