This page describes the modification of a heatsbox from 230v to 12v

• ATTiny1634 microcontroller
• Elecrow_HM-11_bluetooth40_en bluetooth module
• RGB led
• Switch
• 2x 10k NTC Thermistor
• lid closed detection

Likely the ATTiny1634 does not contain an arduino bootloader, since it is only possible to program the controller with a new program from below when selecting the

Board: "ATTiny1634 (No Bootloader)"

from within the arduino IDE.

// red
#define rpin PIN_PA3
// green
#define gpin PIN_PA1
// blue
#define bpin PIN_PA2

int ton = 400;

void setup()


{
  pinMode(rpin, OUTPUT);
  digitalWrite(rpin, HIGH);

  pinMode(gpin, OUTPUT);
  digitalWrite(gpin, HIGH);

  pinMode(bpin, OUTPUT);
  digitalWrite(bpin, HIGH);
}

void loop()
{
      digitalWrite(rpin, LOW);
      delay(1);
      digitalWrite(rpin, HIGH);
      delay(ton - 1);

      digitalWrite(gpin, LOW);
      delay(1);
      digitalWrite(gpin, HIGH);
      delay(ton - 1);

      digitalWrite(bpin, LOW);
      delay(1);
      digitalWrite(bpin, HIGH);
      delay(ton - 1);

      digitalWrite(rpin, LOW);
      digitalWrite(gpin, LOW);
      digitalWrite(bpin, LOW);
      delay(1);
      digitalWrite(rpin, HIGH);
      digitalWrite(gpin, HIGH);
      digitalWrite(bpin, HIGH);
      delay(ton - 1);
}

For this the ATTinyCore from the following page is installed. Instructions are given there as well.