I'd like to build a simple BPM counter for DJ use, that would plug in-line with the output from a mixer to the headphones, and display the bpm (to the the headphones) on a simple 3 digit led display.
I've been looking around the net and have seen others are also after a similar tool, but don't seem to be having any luck.
I believe the basic idea is quite simple : Low Pass Filter to produce a pulse that could be picked up by a counter/timer, which is then sampled over a failry short peroid and is then multiplied to give bpm, which is then sent to a simple LED driver circuit.
If anyone has ideas or circuit diagrams, I'd appreciate the feedback.
Many Thanks,
Derrick