Light theremin

An instrument you play by waving your hand over a light sensor.

Open in Circuit Lab Simulator

Interactive Simulation

Light thereminarduino-uno

Open in Lab

Required Components Checklist

Assembly Steps

Sensor divider

LDR from 5V to A0, 10 kΩ from A0 to GND.

Map to pitch

Convert the reading to 120–1500 Hz and play it with tone().

Arduino Sketch

const int SENSOR = A0;
const int BUZZER = 8;

void setup() {
  Serial.begin(9600);
}

void loop() {
  int light = analogRead(SENSOR);
  int pitch = map(light, 100, 1000, 120, 1500);
  pitch = constrain(pitch, 120, 1500);
  tone(BUZZER, pitch, 40);
  Serial.println(pitch);
  delay(50);
}

Challenges & Extensions

Ready to take this project further? Try these challenges:

•Snap the pitch to musical notes (a scale array).
•Add a button that mutes the sound.
•Calibrate the range during the first 5 seconds.