Author Topic: Same button for two circuits  (Read 948 times)

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Offline hotterTopic starter

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Same button for two circuits
« on: February 06, 2019, 07:46:28 pm »
Hi, I have car mp3 player which I would like to integrate to my car stereo player/steering wheel buttons. So basically I want to reuse same buttons from car to switch songs on mp3 player.
So my question is can I wire different circuit to a button which is used by cars circuit? It could impact another circuit correct? what are my options here if I want to use same button for 2 circuits?
« Last Edit: February 06, 2019, 07:48:17 pm by hotter »
 

Offline ataradov

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Re: Same button for two circuits
« Reply #1 on: February 06, 2019, 10:28:13 pm »
That depends on how everything is connected. In general you can't just share the button.

But what you can do practically depends on what the button in the car is doing and what the button in the MP3 player is doing.
Alex
 

Offline sokoloff

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Re: Same button for two circuits
« Reply #2 on: February 06, 2019, 10:43:51 pm »
Hope that the car steering wheel button is putting the data onto a CAN bus, where you can pick it off the bus easily in digital form and do whatever you want with it.

Google your car model/year, aftermarket headunit control, MCP2515, and CAN bus.
 

Offline Psi

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Re: Same button for two circuits
« Reply #3 on: February 06, 2019, 11:14:20 pm »
Some of those steering wheel buttons are just an analog signal with different value resistors put across it depending on the button pressed.

So if you can find the signal you can tap onto it and read the voltage.

Aftermarket car stereos often have a wire to connect to this, then you go into the options and click "learn" so it can learn what voltage means what button.
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline MavMitchell

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Re: Same button for two circuits
« Reply #4 on: February 07, 2019, 12:06:17 am »
As Psi indicated, the buttons will just be different value resistors connected to ground.
You would have to switch the wire from its original location to your circuit when you want to use then switch it back for its original  purpose, otherwise the original functions would occur.
You might be able to find a function like a long push or something that has no effect on the original that you could detect then electronically disconnect the original for a period while you control your player.
 


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