Debouncing a tap tempo switch.

C

Chris Nixon

Junior
Jul 23, 2012
299
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Northern Ireland
I have a simple normally-open footswitch that I use to input tempo information to my outboard delay unit. The problem is that it will sometimes register a delay of about 20ms when I'm trying to tap in a long repeating delay, presumably due to bouncing of the switch contacts.

Setting a minimum tap value of maybe 50ms on the delay unit would probably fix it, but I don't know of anything that's an option on.

It works fine if I push it with my hand, but it's normally on the floor where I hit it quite sharply with my foot.

There is 3 X 3 X 2 cm of free space inside it for any components I'd want to add. I believe this would involve a capacitor, but I don't know much more than that :) I can solder, and I have some 220uf caps sitting around.

Thanks,

Chris
 
Re: Debouncing a tap tempo switch.

Hello

Since you have opened it - how is it done - open with two wires crossing each other and top of pedal pressing one - is there a chance to put some damping material to shorten the free "tail" so it would not swing and make false contacts.
 
Re: Debouncing a tap tempo switch.

Hi Timo,

The switch is a closed unit, it's an SCI R13-85.

http://www.conrad.com/ce/en/product...-3-A-1-x-OffOn-SCI-R13-85A-05-momentary-1-pcs

http://www.sci.com.tw/PRODUCTS/AUTO ACCESSORIES/(R13) Car Switch/(A3) PUSH/R13-85.htm

I'd thought about physically cushioning it but I couldn't think of a way to do that without interfering with the contacts. It may be possible to get into the casing of the switch, but if I can't do anything electrically it may be easier to change the switch to something that's easier to cushion.

This device is just a switch in a box wired to a female TS jack, so any solution would preferably by passive, or just have huge battery life.

Chris
 
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