Do you own those LED color organs which lights up to the music to? If you don't, and don't even know what I'm talking about, this is this thing:

Color OrganSource:

I wanted to control every spot individually, so I built a controller. It's based on a Atmega 328P which some of you should now from the Arduino Uno. 3 potentiometers control the 3 MOSFETs which control each spot. I used a 4-pin plug to connect the spots to the controller and a standart DC plug from a AC-DC adapter (12V/1.5A) to give the whole system power.

Thanks to @ochsenkopfjack for flashing the code on the Atmega328.

Parts list:

  • 3 P-channel MOSFETs
  • 3 potentiometers with nobs
  • a PCB
  • Atmega 328P with a socket
  • wire
  • housing
  • 10kOhm resistor
  • LM7805 with heat sink
  • Crystal with capacitors


The schematic is for N-channel MOSFETs.

View schematic

Arduino code:

The code is for 3 spots.

int outputValue = 0;
int sensorValue = 0;

void setup() {
	analogWrite(9, 255);
	analogWrite(10, 255);
	analogWrite(11, 255);

void loop() {
	//Spot 1
	sensorValue = analogRead(5);
	outputValue = map(sensorValue, 0, 1023, 0, 255);
	analogWrite(9, outputValue);
	//Spot 2
	sensorValue = analogRead(4);
	outputValue = map(sensorValue, 0, 1023, 0, 255);
	analogWrite(10, outputValue);
	//Spot 3
	sensorValue = analogRead(3);
	outputValue = map(sensorValue, 0, 1023, 0, 255);
	analogWrite(11, outputValue);
	//Wait a moment for restart



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