Quote Originally Posted by jwulf74 View Post
Our bicycle speedometers use a magnetic system to calculate the speed of the bike... just a magnet on the spoke and a sensor on the fork. I think even the cheapest ones do that now. If a guy could reverse engineer one of those to trip a relay at x speed, that may be a possibility. way beyond my low level of expertise though.
But how do you tap the signals off the unit? It is a closed system whereby signals from the sending unit is send to the display.... like you said, that guy must have a Phd in electronics to be able to do it... way beyond mine too...