Adafruit Soundboard FX Help Needed For Public Art Project

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thisismyname
 
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Adafruit Soundboard FX Help Needed For Public Art Project

Post by thisismyname »

I'm using an Adafruit FX Soundboard to have an old payphone play a random sound when the handset is lifted from the cradle. When the phone is removed from the cradle, a button is held down inside the phone, and the sound plays. The issue I'm having is when the phone is off the cradle, the button is continuously held down until the phone is hung up. This causes all the sounds to be played one after another while the phone is off the cradle.

Is there a way to have only one sound played even if a button is held down?

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dastels
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

Post by dastels »

Unfortunately for your usecase, the trigger inputs are level sensitive, not edge sensitive. What you want to do is create a low pulse from the closing of the switch.

You could use a 74LS121 Monostable Multivibrator chip with a transistor to switch the trigger to do the job. See https://www.ti.com/lit/an/slva720a/slva720a.pdf. I'll play around and come up with the circuit this afternoon.

Dave

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dastels
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

Post by dastels »

Here's the circuit. I used a 10K resistor and a 22uF capacitor.

Dave
IMG_5954.jpg
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thisismyname
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

Post by thisismyname »

Dave. This is super cool! I'll try it, but it might be slightly over my skill level :)

I was trying to find a switch that would reset itself internally once it was pushed, even if it was held down. Something that would provide a contact for a second and then disconnect internally. Like a spinning contact wheel of a sort. Ever heard of a switch like this?

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dastels
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

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No, I haven't heard of anything like that.

Dave

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dastels
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

Post by dastels »

Anyway, that circuit will give one, fixed duration low pulse to the Audio trigger for each press of the button, regardless how long the button is held closed.

Dave

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amp1276
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

Post by amp1276 »

I am doing the same project and have the same issue. I would also prefer not to create an additional circuit to correct the issue. I know there is such a thing as a momentary leaf switch with a small wheel to allow the pressing mechanism to roll off. Does anyone have any mechanical way to manage this?

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thisismyname
 
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Re: Adafruit Soundboard FX Help Needed For Public Art Project

Post by thisismyname »

I figured out a workaround. If you use the "Play Random Trigger" it continues to play all the sounds, but if you use the "Play Next Trigger" it only plays a single sound and then stops. Not sure why this works, but I was happy it did.

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