Arduino UNO R4 Sound Sensor: Detect Claps and Trigger LEDs

Original tutorial:Arduino UNO R4 - Sound Sensor (newbiely.com)

A sound sensor is the cheapest way to give an Arduino UNO R4 an ear. It will not tell you what it heard - it tells you that something was loud enough. That turns out to be plenty: clap to switch on a lamp, bang to trigger a relay, knock to wake a servo.

Two flavours of the module

• Digital - one OUT pin, a plain ON / OFF signal.
• Analog - a DO pin that behaves like the digital one, plus an AO pin that gives you a continuous loudness value.

Both carry an electret microphone, a comparator, a sensitivity potentiometer, and two LEDs - one for power, one that lights when the threshold is crossed.

The one thing that trips people up

The output is inverted. Silence reads HIGH; a sound pulls the pin LOW. If your sketch seems to be firing constantly, it is almost certainly this and not the wiring.

Wiring

• VCC to 5V (the module is happy anywhere from 3.3V to 5V)
• GND to GND
• OUT (or DO on the analog board) to pin 8
• On the analog board, AO to any analog pin if you want a loudness reading as well

No library needed - pinMode(8, INPUT) and digitalRead(8) is the whole API.

Tuning the potentiometer

This is the part worth spending a minute on. Turn the little screw until the status LED sits just off in a quiet room, then claps light it and normal talking does not. Too sensitive and the sensor triggers on everything; too dull and you have to shout at it. Useful range is about 10 inches.

Code

Two sketches - a bare detector that prints sound events to the Serial Monitor, and a clap-controlled LED demo with four patterns (Blink All, Water Wave, Inside Out, Random Dance). Both live in the original tutorial rather than being repeated here:

https://newbiely.com/tutorials/arduino-uno-r4/arduino-uno-r4-sound-sensor

If it misbehaves

• Status LED stuck on or stuck off: turn the sensitivity pot, not the code.
• Random triggers: the module picks up vibration through the bench. Screw it down to something solid.
• Erratic readings: it is an analog front end, so give it clean power. A noisy supply shows up as phantom claps.

Full tutorial, wiring diagram and complete code:https://newbiely.com/tutorials/arduino-uno-r4/arduino-uno-r4-sound-sensor