Speed climbing is about tenths of a second, so a speed wall needs a proper clock to go with it. Timeotron 3000 is a small microcontroller board with two buttons, start and stop, and a large display built from eight 8×8 LED matrix modules (MAX7219, 4×2) driven through the MD_MAXPanel library.
At power-up it runs a quick display test (00.0, 11.1 … 99.9). Pressing start begins counting, with the elapsed time shown to a tenth of a second, and stop freezes the result on the display until the next start, while the EasyButton library takes care of debouncing both buttons.
This was the first of my timing devices for climbing gyms, the ones that later became part of Backdoor.