Mechanical interface conversion to a software interface.

Discussion in 'The Projects Forum' started by jester1, May 18, 2016.

  1. jester1

    Thread Starter Member

    Feb 10, 2011
    I"m working on taking the control panel from my cars stock head unit which has buttons, and converting it into a piece of hardware and software I can control from a touch screen from a windows os over usb. Attached is the circuity I reverse engineered from the controller board.
    stereo switch circuit.jpg
    Each of the switches, controls a different function for the stock stereo. So from there I ordered myself a sainsmart 16 relay module and the usb controller to go along with it. The source code supplied with it is in C++, and doesn't function to say the least. I'm not a savvy programmer, I can figure out how to hack whats already been done to serve my purpose, but not create it from scratch, or troubleshoot why it doesn't work to begin with. Already ordered plan B for when that doesn't pan out, an arduino uno, which with some research brought a plethora of information and projects on how to work with it. To me though replacing the push button switches with relays is the lazy way to go, and also somewhat bulky. I've been trying to figure out an alternate route using just the arduino to supply the grounds to the specific points of the circuit, without putting 5 volts into the circuit at those points in the inverse (pin low for on and pin high for off). I'd suspect the head unit would not like that, and I'd really prefer not to blow it up. So to my questions, is there a way to send the grounds using the arduino without sending power in the inverse, or is the relay route my only easy option. Another question that arose while reverse engineering the board, was what the point of the diode capacitor pairs was. All of them were smd components so determining 100% what they are was a shot in the dark to say the least, I somewhat figured the diodes out, but the capacitors was a guess with my multimeter. Thanks for any help in advance.