Arduino Theremin Wiring Diagram
Pin connections and code outline for the ultrasonic theremin build.
HC-SR04 Wiring on Arduino
Four-pin sensor: VCC (5V), Trig (output), Echo (input), GND.
HC-SR04 Wiring on Arduino
Pitch sensor: - VCC → 5V - GND → GND - Trig → GPIO 9 - Echo → GPIO 10 Volume sensor: - VCC → 5V - GND → GND - Trig → GPIO 6 - Echo → GPIO 7 Audio output: - GPIO 11 (PWM) → PAM8403 amplifier input - PAM8403 power from 5V rail, output to 8Ω speaker
Code Structure Overview
Measure distance, map to frequency and volume, output tone.
Code Structure Overview
In loop(): Read pitch distance with getDistance(trigPin1, echoPin1). Map value 5..50 to frequency 200..2000 Hz with constrain() to limit out-of-range values. Read volume distance with getDistance(trigPin2, echoPin2). Map to 0..255 for analogWrite() duty cycle. Call tone(11, frequency) to set pitch. Use analogWrite(11, volume) for amplitude — note: tone() and analogWrite() conflict on the same pin; use separate output pins or a DAC module for both.
tone() and analogWrite() Conflict on AVR Arduino's tone() uses Timer2 on GPIO 11. analogWrite() also uses Timer2 on some pins. To control both pitch and volume independently, use a different timer for volume: an external I2S DAC module or a separate PWM channel. Alternatively, use an Arduino Due or Teensy which have dedicated DAC outputs.