i'm having the hardest time finding online resources for schematics projects. i want to build a simple digital counter to count rotation (like a shaft or a wheel) by means of magnetic sensor. i know that cyclometers do this, but it's a project i want to build, not buy. any ideas? if someone could link me to a geek hobby forum or site that has free schematics (i don't want to have to buy a book or join a club if i can help it) it would be great.