For those of you with a penchant for changing gears at "exactly the right time" when driving or riding hard - this project by Kostas Kokoras will be of interest. Kostas has published details of how to build a device that inductively detects the change in current through a spark plug cable - which can then be used as part of a function to determine the RPM of the engine. Then you can simply enter the ideal shift points into the Arduino sketch and have an LED (etc) activate when it's time to shift up a gear. For an quick demonstration, check out the results on Kostas' motorcycle in the video below:
It's an interesting project that could be adapted to all sorts of engine and vehicle types - so for schematics and example sketches, head over to Kostas' interesting website. And for more, we're on twitter and Google+, so follow us for news and product updates as well.