Optical Theremin With Arduino Uno

A theremin is an electronic instrument in which two high-frequency oscillators control tone while the musicians hand movements control the pitch.

In this Instructable, we'll build a similar instrument, in which hand movements control the amount of light that the instrument's sensors receive, and that light measurement is converted into a resulting pitch from a buzzer.

Parts you'll need:

Arduino microcontroller

Breadboard

10 K Ohm resistor

Jumper wires

1 Piezo Buzzer

Photoresistor

Start by connecting your breadboard's positive row to the 5V pin on the Arduino Uno.

Then connect one of the GND pins to the negative line on your Arduino.

Insert your buzzer. It likely has a longer leg, or a small "+" sign on the top. Keep track of which side the longer leg or "+" sign are on.

Connect the shorter leg of the buzzer to ground by inserting a wire in the same row as the shorter leg of the buzzer, and in the negative line on the breadboard.

Complete the buzzer circuit by connecting it to pin 12 on the Arduino.

Start building the photoresistor circuit by inserting the photoresister so that it has one leg on each side of the channel down the middle of the breadboard.

Use a wire to connect one leg of the photoresistor to the positive line on your breadboard that you connected to 5V earlier.

Connect the photoresistor's other leg to ground, connecting the 10K Ohm resistor to the negative line on your breadboard.

We'll read the change in current through the resistor by connecting a wire between the photoresistor and its ground wire, back to pin A0 on the Arduino.

int analogPin = A0;

int noteToPlay;

int sound; int speaker = 7;

void setup() {

Serial.begin(9600);

pinMode(analogPin, INPUT);

}

void loop() {

sound= analogRead(analogPin);

delay(200);

int notes[21] = {65, 73, 82, 87, 98, 110, 123, 131, 147, 165, 175, 196, 220, 247,262, 294, 330, 349, 392, 440, 494};

noteToPlay= map(sound, 0,1023, 0, 21);

tone(speaker, notes[noteToPlay]); delay(10);

}

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