FX Sound Board

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Nuch10
 
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FX Sound Board

Post by Nuch10 »

I have a keyed switch I would like to use to turn on leds and leave them on until the switched is turned off.
I would like for my FX sound board to trigger at the same time the lights come on and play a "power on" sound only once until power is cycled.
I have this all wired and working, however..
Currently the sound loops because ground is always connected.
I read in one of the other posts that someone worked around this by connecting a 10uf capacitor between the trigger and ground.
Does anyone have experience with this?
Can I use a 10uf @ 50v capacitor?
Do I need a resistor in there?

Thank you in advance

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dastels
 
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Re: FX Sound Board

Post by dastels »

Yes, a 10uF 50v cap will work fine. You are well under the 50v rating.
Yes, it's the combination of the resistor and capacitor that creates the delay.

I answered this a while back:
I played around with this and came up with a simple solution. Put a 22uF capacitor between a trigger input (I used 0) and ground (watch the polarity) and a 100k ohm resistor between that the same trigger and Vin (I tested with 5v). The capacitor starts empty so the voltage on the trigger is 0v. So that triggers T00. The capacitor slowly charges through the resistor and eventually the voltage on the trigger pin is high enough to "turn off" so the sound only plays once. You'll get one play when power is applied.

If your sound is short and gets triggered multiple times before the trigger turns off, use a smaller resistor.
In retrospect, each trigger pin has a 100K pullup so you actually could just use a capacitor and rely on the pullup to charge it. In that case, a 10uF is a good place to start.

Dave

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Nuch10
 
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Re: FX Sound Board

Post by Nuch10 »

Thank you for the quick response!
Really appreciate the feedback.
I will give it a try.

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