If you’d like to measure the speed of your cycling then it’s easy enough to buy a cycle computer, but as [Clovis Fritzen] has done it’s also an option to build one. The result of his work is a smart PCB on which the speed is indicated with a row of LEDs.

The sensor is a straightforward affair, a reed switch with a magnet on a wheel, which is sensed by an ESP8266. The six LEDs are charlieplexeed over three lines. To keep the supply voltage correct for the ESP from the uncertain state of a lithium battery, a small buck-boost module is used. Sadly the code doesn’t seem to make the speed available via the wireless part of the processor, but we’re guessing that a bit of extra software work could fix that.

The result when put in a box on the handlebars, is a smart but simple instrument that would aid any bike. It’s by no means the first one we’ve brought you and we doubt it will be the last.