a low cost muscle switch with a usb interface to command a computer with any scrolling interruption software ( like the famous ACAT used by Stephen HAWKING https://01.org/acat/switches)

The sensor is a simple piezo tranducer.

It is interfaced to an arduino Clone with ATMEGA32U4 controller.

This controller has integraded HID functions : it can trigger a keyboard or mouse event.

The raw piezo signal is analysed with peakDetector Library.

When the signal overcomes a limit tunable with the potentiometer, it triggers a keyboard event and powers the LED on (F12 Press for example )

CJMCU BEETLE Keyboard BadUSB ATMEGA32U4 DC 5V 16MHz MINI Development Board 19.92 Cable jack 3.5 mm 0.79 Buzzer piézo RS PRO 724-3162 0.75 Potentiometer B5K 1.4 velcro round pad fixation 0.28 arduino jack audio module 1.26 PCB proto board 3x7 1.18 simple LED 0.2 3M Resistor 0.2 327 ohm Resitor 0.08

Total : 26.06 €

A0, A1 : analog input on arduino D9 : digital output on arduino