Convert/invert the OPEN/CLOSE signal from Single Cup Headphones to the Adafruit Audio FX Mini Sound Board (newbie)

Thread Starter

Offrecord

Joined Mar 20, 2022
3
What I want is for a sound file to start playing from the beginning when I remove headphones from a magnet stand. When I put the headphones back on the stand, the sound will stop.

This is the equipment I have for this project:
Headphones: AutoPlay Single Cup Headphones from Blackbox-AV
The headphones comes with an audio cable with a standard mini jack connector, as well as two cables from the built-in switch.

Sound Board: Adafruit Audio FX Mini Sound Board - WAV/OGG Trigger 16MB Flash
The audio sound board comes with 11 inputs for triggers. They are activated when the board receives a CLOSE signal.

When I lift the headphones from its stand, the signal from the built in switch is OPEN. The signal is CLOSED when I put the headphone back on the magnetic stand.

With the switch signal cables from the headphones connected the Audio sound board, the audio stops when I lift the headphones and resumes when I place them back on their magnetic stand. Basically, the inverse of what I desire.
Is there a magical device (perhaps a relay?) or something I could hook up to "invert" the signal flow so that when I lift up the headphone, the audio begins to play. I'm new to electronics and hoping for a simple solution that doesn't require too many parts. If necessary, there is a 5V BUS output on the sound board that I can use to power a relay.
 

ElectricSpidey

Joined Dec 2, 2017
2,146
Actually, the FX Mini is triggered when a pin is pulled "LOW" for 125ms, with an internal pullup resistor that keeps the pin "HIGH" when there is no signal.

You may be able to do what you want with an NPN transistor instead of a relay.
 

BobTPH

Joined Jun 5, 2013
4,907
You can do this very simply. Put a 10K resistor from the input to ground. Then connect the switch on the stand between the input and the positive supply of the player. When the headphones are on the stand, the switch holds the input high so it does not play. When you lift them, the resistor pulls the input low and it plays.

Bob
 

Thread Starter

Offrecord

Joined Mar 20, 2022
3
You can do this very simply. Put a 10K resistor from the input to ground. Then connect the switch on the stand between the input and the positive supply of the player. When the headphones are on the stand, the switch holds the input high so it does not play. When you lift them, the resistor pulls the input low and it plays.

Bob
Thanks Bob. I will try this today. Thank you for your suggestion.
 

Thread Starter

Offrecord

Joined Mar 20, 2022
3
You can do this very simply. Put a 10K resistor from the input to ground. Then connect the switch on the stand between the input and the positive supply of the player. When the headphones are on the stand, the switch holds the input high so it does not play. When you lift them, the resistor pulls the input low and it plays.

Bob
Where can I locate the positive supply on the player?
https://cdn-learn.adafruit.com/asse...iginal/adafruit_products_schem.png?1411508346
 
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