After some searching, I ended up using a microcontroller and a piece of code borrowed from the web that I tweaked and adapted. The microcontroller-based concept was chosen because I wanted to scale ...

Using an Arduino and a servo he built a classic needle speedometer for his bike. It also has a digital display and uses a hall effect sensor to pick up the wheel speed.

The IR sensor array, which on the palm-sized vehicle consisted of just a handful of components, evolved into a PCB-backed bar nearly 0.5 meters wide. Potentiometer tuning was a fiddly affair, but ...