Adafruit carries a lovely foot switch which has a single pole-double throw switch inside. The switch can activate a number of items including an alarm or powerswitch tail to control your world.
A much-requested project by Adafruit customers is using the foot switch to interface with a PC via universal serial bus (USB). To get a switch activation to talk to the USB bus takes a controller – some smarts.
Adafruit’s ATtiny85 based Trinket is low cost and contains enough smarts to perform USB communication (via some smart library software).
Only three parts are required. The foot switch, a USB A to Mini-B cable, and a Trinket 5V. The entire project costs less than $20. And it takes less than an hour’s work.
The wiring is shown above. The existing foot switch wires are cut short and two connected to Trinket pins #0 and GND (ground). When the foot switch is activated, the switch contact pair that creates a short connects Pin #0 with ground. When the Trinket detects the pin connected to ground, it outputs one or more characters as a PC keyboard.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.