Tab Stomper prototype 2 (V-USB, breadboard)

2018-02-20 (updated 2018-04-07)

Hardware

The previous prototype had too many wires flapping in the breeze, and it was taking up an Arduino for no good reason. The revised version sits on a single breadboard: This version still uses the V-USB development board, so there's nothing on the breadboard besides an ATmega328P (in a ZIF socket) and a 16 MHz crystal (without any load capacitors!). The USB VBUS and GND are fed from the V-USB board into the microcontroller. The pin layout is unchanged from before, but now there's no mapping to "digital pins": PD2 (pin 4), PD3 (pin 5), and PD4 (pin 6) go to D+, PU, and D-; the button sits on PD5 (pin 11).

The previous foot switch was unreliable and didn't last very long, since it was only held together with electrical tape. I took the guts out and instead nailed a microwave door switch to the Altoids tin: A piece of plastic taped to the lid presses the button: This feels much sturdier and makes a very satisfying click.

Here's what it looks and sounds like in action:

Firmware

The firmware is unchanged from the previous prototype. It still uses V-USB and lives on GitHub.