Tachometer made from a Bicycle Computer

A clever way to use a bicycle computer as a poor-man’s tachometer. While I’m not sure about installing it in my car, I’m sure it’ll come in handy down the road for another project.

"Sometimes you just have to know how fast a wheel or shaft or motor is turning. The measuring device for rotational speed is a tachometer. But they are expensive and not easy to find. Its cheap and easy to make one using a bicycle speedometer (cyclocomputer). In fact, the only thing you need is a functional cyclocomputer that reads speed in miles per hour. You won’t damage it, so you can even ‘borrow’ one from your bike, or add it to your bike once your done!"