Build a mini piano

Why it’s here

Hold the on-screen copper keys and compare the displayed note frequencies.

How it works

Eight copper pads use capacitive touch to play an octave. No. This course targets the original ESP32 touch peripheral. Check your exact chip and calibrate untouched values. This guided model targets the original ESP32 and Arduino-ESP32 3.x; radio, acoustics, loads and mechanics are simplified.

Try it

1. Open this experiment
2. Hold the on-screen copper keys and compare the displayed note frequencies.

Connections

• 4,13,14,27,32,33,15,12 — Eight touch pads C4–C5; avoid strap interference at boot
• GPIO 25 / GND — Passive buzzer

Example sketch

const int pads[] = {4, 13, 14, 27, 32, 33, 15, 12};
const int notes[] = {262, 294, 330, 349, 392, 440, 494, 523};
// Original ESP32 only. Calibrate touch threshold; GPIO12/15 are boot straps.

void setup() {
  ledcAttach(25, 1000, 8);
}

void loop() {
  int note = 0;
  for (int i = 0; i < 8; i++) {
    if (touchRead(pads[i]) < 30) { note = notes[i]; break; }
  }
  ledcWriteTone(25, note);
  delay(10);
}

Check your understanding

Is touchRead available on every ESP32 variant?