tap tempo switch with audio input

[engels]

 
Hello everyone, I'm thinking about buying BOSS DD-7 which seems to be a very nice delay, but it does not have a function to accept tempo from an external device, like midi in. Only a footswitch socket, and you can use a regular footswitch to tap tempo.

I wanted to make some sort of a device converting input audio signal, for instance - from drummer's metronome - into on-off sort of output which can replace a footswitch. So I will always be in sync with drums and any time I turn the delay on it will already be in the right tempo.

I've found some scheme of BOSS footswitch, but it's basicaly just a simple footswitch, nothing fancy.


I understand I need some sort of relay to transform audio input into "on" and silence into "off", probably with some preamp for the audio input - maybe a schmitt trigger to convert it into square pulse. This thing should be powered by 9V supply of my pedal board.

[engels]

So first, I've never had any experience with relays before, what type of relay should I look for?
Then, of course, I'd like to hear how would you solve this convertor?

[Kearns892]

This sounds a lot like a digital endeavor (though a very cool and useful one). If digital is what you have in mind, I would suggest posting this in the digital section of the forum as you may get more hits there.

Sounds a lot like what the TC electronic nova delay and nova repeater do. I would check them out for ideas.

[Hides-His-Eyes]

If you can guarantee a clean click (from a metronome or decently isolated bass drum mic) you can do this using a lowpass filter, rectifying the signal, sending it into a Schmidt trigger and using that to drive a transistor switch or relay. No digital needed.