analog input protection & analog control signals

FrancisHarmany · Post by **FrancisHarmany** » Wed Sep 01, 2004 6:23 am

Hi guys,

I want to build my own touch sensitive trigger device. Take an old bongo, do some stuff, and then when I hit it I want to signal togo to analog input of my card. Then I can route it to modular synth and tadaaa... more live control!

I am sure I need protection to make sure the signal doesnt fry my soundcard (too much voltage ?)

So I could use any and all advice on how to create such a setup.... what possible tools to use as protection. Would mics be usuable on stage or would I get in trouble with sounds from speakers also going into the mic. etc. etc.

Any ideas ?

blazesboylan · Post by **blazesboylan** » Wed Sep 01, 2004 12:20 pm

Cool project!

Drum trigger pads are often made with piezoelectric pickups. Some acoustic guitars use them, too. You can buy them at Radio Shack in N. America.

Building a limiter is a pretty complex process unless you're comfy with op amps. Beyond my comprehension!

Make sure you post photos of your setup when you're done, eh?

Cheers,

Johann

wolf · Post by **wolf** » Wed Sep 01, 2004 2:29 pm

If you take care about current, not only voltage, there shouldn't be any problem.
I'd be more concerned about the speakers

I'd get some old simmons drums for cheap and take their module triggered via a piezo resistor.

best
Wolfgang

_________________
<a href="http://www.worldless.com/sfp">wolf audio design</a>
<a href="http://www.worldless.com">worldless productions</a>

[ This Message was edited by: wolf on 2004-09-01 15:33 ]

[ This Message was edited by: wolf on 2004-09-01 15:38 ]

at0m · Post by **at0m** » Wed Sep 01, 2004 11:51 pm

I have an old Pearl Syncussion SY-1 here, it works like that... It's a dual analog synth, triggered (and muted if wished) by up to 4 toms. They look exactly like toms, and are a bit heavier as if they were filled with sand. It was used to boredom in the late 70's in disco and 'black' music.
Only 2 of the original toms are with the SY-1 here, I used a PZM mic on it too.

http://edrum.for.free.fr/ has a decent explanation on how to DIY triggers.

FrancisHarmany · Post by **FrancisHarmany** » Thu Sep 02, 2004 12:50 pm

Is it even possible to fry my soundcard ?

blazesboylan · Post by **blazesboylan** » Thu Sep 02, 2004 1:20 pm

Sure. If you want to test it, get a DC power supply and an amplifier and keep turning up the voltage until your SHARCs melt.

It would probably be hard to do it with a pickup though. You're likely to get distortion loooong before you sizzle your chips.

(I'm not an expert at this stuff though so hopefully one of the gurus will post a comment too.

)

nprime · Post by **nprime** » Thu Sep 02, 2004 3:29 pm

i've used the radio shack piezo's going into a roland octapad to create midi triggers, but never tried it for audio. I don't think the basic output from a piezo will fry your sound card, it's a pretty small output voltage. If you are worried then just run it through a mixer first so that you can turn down the gain.

I attached the piezo directly to the skin of the drum with duct tape, but this ruins the sound of the drum, just tape it to the inside of the shell. BTW piezo's aren't exactly hi fidelity, your bongo will not sound like a bongo unless you use a mic. As well you will have potential feedback problems with a mic mounted inside the bongo.

Just send the live mic signal (that you are already using to mic the bongos) via a board's aux bus to your sound card? this would be relatively simple.

Good luck!

R

[ This Message was edited by: nprime on 2004-09-02 16:34 ]