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Using a Car Door Pin to trigger an Event with an Trinket
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Using a Car Door Pin to trigger an Event with an Trinket

by joshuakane on Thu Apr 14, 2022 11:14 am

Hello,

I was thinking of setting up a Trinket to launch a sound event on one of the AudioFX boards. In this case I want a sound to play every time I open my Car Door. I know the AudioFX board has triggering for button state changes, but I was wondering how to trigger it for a door pin that is always closed? I want the event to fire when the door opens. Would it be as simple as setting the pin to "LOW" and when it opens setting it to "HIGH"? I I wanted to use the existing door wiring for the pin. It looks to just be a wire delivering current that is "off" when the door is closed and "On" when it is open. Can I attach to this, and run ground to the body of the car to tell when the state changes?

Thanks,

Joshua

joshuakane
 
Posts: 282
Joined: Sat Apr 13, 2013 4:40 pm

Re: Using a Car Door Pin to trigger an Event with an Trinket

by mikeysklar on Thu Apr 14, 2022 12:41 pm

Joshua,

You have the right idea with the AudioFX. I don’t see the Trinket as being necessary.

If you can wire your door to pull to ground when open (eg. play sound). If for some reason the existing built-in cannot be used there are other conductive materials and sensors that might work for you as alternatives.

Remember, you don't have to use a mechanical button or switch - you can use conductive thread, tilt switches, two pieces of tinfoil, the output from some other electronic thingy, just anything that will send a ground signal to the pin.


https://learn.adafruit.com/adafruit-aud ... ring-audio

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Re: Using a Car Door Pin to trigger an Event with an Trinket

by joshuakane on Tue May 10, 2022 4:02 pm

On this one, I decided to go just with the AudioFX.

If I connect it to the existing door pin I get the following behavior

1) Tnn - (Button Push) Sound plays over and over again, as long as the car door is open
2) TnnLATCH - (Latching) The door plungers are on a spring, so the latching files will only work every other open

Is there a way I can set it to just play the sound once on opening the door?

Thanks,

Joshua

joshuakane
 
Posts: 282
Joined: Sat Apr 13, 2013 4:40 pm

Re: Using a Car Door Pin to trigger an Event with an Trinket

by mikeysklar on Wed May 11, 2022 5:14 pm

Initially I thought a basic trigger would have worked since it is only supposed to play the Tnn audio file once from beginning to end. The Advanced Background/Foreground suggests adding a NC (normally closed switch) in the circuit to avoid the looping problem.

https://learn.adafruit.com/adafruit-aud ... -1137397-8

The problem here is that you can't release the looping sound since its tied to ground. You could have one button held down all the time or try a latching loop but it's a lot easier if you just use a switch that has NC (normally closed) and NO (normally open) contacts - sometimes called a DPST (double pole single throw) switch

Most low cost switches and buttons do not have a normally-closed output, so make sure to check the specifications. This switch is a good example of one with both, and it even has nice markings!

mikeysklar
 
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Joined: Mon Aug 01, 2016 8:10 pm

Please be positive and constructive with your questions and comments.