Switch questions

[caguaman]

Hello all!

I found a disassembled midi controller keyboard.

I wanted to use it connecting some push buttons as the keys and be able to play with my feet. The problem I have is that the circuit there is different from what I have seen (Note: I'm a begginner and I have not seen many keyboards PCB's). It has 2 switches per key. The switches are similar to the ones in the picture, activated by rubber strips with carbon pills, and are very close to each other.

From the info I could find, this is used for velocity sensing (not sure).

Seems like the time difference between activating one switch end thenthe other is what gives a time reference and results on higher or lower volume as if I'm hittig the key harder or softer.

Each switch seems to be connected to a different circuit so when they are activated, the signal seems to go first to one circuit then to the other.

I want to use just one switch.

I already tried leaving one of the switches closed but it doesn´t work. Does anybody knows if there´s any simple way or trick to close switch 1, then delay the signal that goes to circuit 2?

Hope I was Clear...

Thanks!

 

[Resqueline]

Not that I know, but I'd figure the key hit speed sensing rather relies upon the speed of resistance change, since the carbon pills exhibits variable resistance with pressure.

 

[shrtrnd]

The picture and description is for a very common type of switch.
But that's ALL it does. They're not INTENDED to vary resistance.
I'm thinking from what you've said, you'd use your feet to hit one, then another, then another switch, to increase your volume. That's the CIRCUIT the switches are connected to, not the switches themselves.
Depending on the circuit, it would be simpler to just have one switch, and each time you
close it, the circuit would incrementally increase your volume (but that depends entirely
on your circuit).
I'm thinking we need more info on your circuit, to tell you what best to do.

 

[caguaman]

Thanks for your replies.

And sorry because I was not clear.

What I meant is that I want to replace each keyboard key switch with a button switch that I would put on a board so I can play the keyboard with my feet (hehe sounds a little bit crazy but...)...

With other keyboards this is easy to do because you only disconnect the pcb with the switches and rewire with common button switches.
The problem with my keybard, is that per key, there are 2 switches. and seem to be connected to different circuits. As I said before, Ithink this array is used for "velocity sensing".

If you hit the key hard, both switches will be activated almost at the same time and this results on a louder sound. If you hit the key softer, the time between activating one switch and then the other is bigger and this results in lower volume sound.

Now, I don't care about velocity sensing. I just wanted to emulate a switch being activated and then the other and I wanted to emulate this by delaying a little bit the signal for the second circuit after activating the button switch. I assume this at least will give a constant velocity for all the keys, but how to delay the signal??

Again, hope I was clear...

Thanks