Hot Wire Foam Cutter - Arduino PWM




Introduction: Hot Wire Foam Cutter - Arduino PWM

About: Software, electronics, do-it-yourself

Last time I did the Hot wire foam cutter but I missed the temperature control. So that's why I made a simple PWM control. The whole project was based on Arduino ATtiny85 Digispark. For this project I only needed three pins, so the ATtiny85 is fine. Also I carried the wires in the PVC pipes. This article can also see here:

Hot wire foam cutter - Arduino PWM

Hot wire foam cutter

Step 1: Components

  • Arduino Digispark ATtiny85
  • Plastic box for electronics
  • Some wires
  • IRF530
  • 5 x resistors 1k ohm
  • 2 x resistors 100 ohm
  • 1 x potentiometer 10k ohm
  • 2 x BC547
  • 1 x LED 3v
  • 1 x 7812
  • Hot wire foam cutter

Step 2: Schematic Diagram

Step 3: Fixing

After soldering the circuit, we can mount it to the PVC pipe.

Step 4: Wires

The next step is to place the wires inside the PVC pipe.

Step 5: Software for the Controller

The software itself is very simple.
#define LED_PIN 0
	#define PWM_PIN 1
	int val = 0;
	long t = 0;
	bool sw = LOW;
	//the setup routine runs once when you press reset:
	void setup() {                
	  pinMode(LED_PIN, OUTPUT); //LED on Model B
	  pinMode(PWM_PIN, OUTPUT);
	  analogWrite(PWM_PIN, 0);
	void loop(){
	  val = analogRead( A1 );
	  analogWrite(PWM_PIN, val/4 );
	  if( millis() - t > 1000 ){
	    sw = !sw;
	    digitalWrite(LED_PIN, sw);
	    t = millis();
Download source code: Hot_wire_foam_cutter.ino

Step 6: Programming ATtiny85 With Arduino IDE

  1. Select board digispark (Default - 16.5mhz)
  2. Select programmer micronucleus
  3. Press upload and connect ATtiny85 Digispark to USB. You have 60 seconds to do it.

  4. Wait until it's over

Step 7: The End

Work finished time to test Hot wire. Soon it will be Easter, so I will cut out Easter bunny.

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    4 Discussions


    1 year ago

    Nice work, schematic works great. I you want to pulse the LED to the current frequenzy of the PWM, change the code at "if( millis() - t > 1000 ) " to "if( millis() - t > (1023 - val) ) ".


    3 years ago

    I like the build. Out of curiosity could you have done the same thing with just the POT in line? Or are you looking to do more with the arduino in the future?


    Reply 3 years ago

    Using a pot "in line" with a heater/bulb/motor etc. rarely works out well. The currents involved will burn the pot up. Pots (carbon track and similar) are intended for low current and signal levels.

    If you mean something out of a museum, such as a rheostat, or a giant wirewound pot, then maybe. But it's still an inefficient way to do it.

    I control the temperature on my hot wire cutter by just turning the voltage up and down at the variable power supply :)


    Reply 3 years ago

    In the future I intend to do a bit bigger. For the project I also will use Arduino, temparatury adjustment is useful.