Car Stereo Remote Control

[iMagoo]

Hi guys,

New member so take it easy on me!

Alright, so I'll give a bit of background. I want to create an interface for my car that works from the steering wheel radio control buttons (volume up, down, mute etc.) and communicates to an aftermarket car stereo through IR signals in order to enable the steering wheel controls.

For transmitting the IR signal, a basic PICAXE IC with infra-red LED should suffice.

However, the issue I am having is coming up with an idea to connect the steering wheel buttons to the PICAXE. The buttons work by having different resistances and the output is a single wire. I would have to grab my multimeter and splice this wire to determine the voltage range for each button.

Question is, how do I work these resistance (and therefore voltage) varied buttons into a circuit with a PICAXE IC?

Thanks

 

[(*steve*)]

Use an analogue input.

Use the variable resistance (switches) in series with another resistor to make a voltage divider. Then read off the voltage and use that to determine what switch is pressed.

You will need a regulated voltage an to allow a range for each switch, but there's nothing really difficult.

 

[mechtronics]

you can buy Stalk adapter leads that cater for steering wheel controls use to after market radios.

 

[CocaCola]

I believe CDRIVE has already addressed this design (or one very similar in regards to a one line multiple value input) recently on the forums with a PICAXE solution, if not he has certainly addressed a similar design... I'm sure a little searching will pop the threads...

 

[CDRIVE]

It took a bit of time to find it. As we've discussed in the nubies secret circuit circus thread, topic names are,... uh,... well we all know..
https://www.electronicspoint.com/flasher-circuit-negative-switching-t249698.html

Actually, this one ain't too bad!

Chris