My Solution To Steering Wheel Controls
Well everyone I had another hair brained idea :D
I wanted to have steering wheel controls in my car but
1. I didnt want to modify the cars stock wiring
2. I was not able to safely route a wire up through my steering column to get to the control buttons.
Since I had 12v present inside the steering wheel I decided to go with a microcontroller and some $17 wireless modules from sparkfun. So not only can I wirelessly send button presses to the computer in the trunk I have endless possiblities for button combinations in the future. I could even add datalogging of sorts. So 2 microcontrollers and about 10 PCB's later I ended up with this.
The PCB on the top is a receiver board I created and the board on the bottom is of course the transmitter board. I used a PIC 16F628 for the transmitter board, because well I had one already and I wanted expansion for later on so with 1k of code space and i'm only using 1/3 of it I should be fine. The receiver is using a PIC16F458 which yes is way overkill for what it is doing right now. I will be downgrading it to a F628 when I get it.
The receiver board has a standard PC DB9 connector which i'll use to connect to my computer.
Here is a closeup of the transmitter board
Here is a picture of the steering wheel buttons I ordered from volvo.
This is the transmitter board with the PIC in it's socket and the TX module mounted.
just have to finish wiring everything up
there is a picture of the stock volvo pcb and the bottom of my board
And finally there is everything next to a quarter for a size comparison.
So thats pretty much all the hardware and it's pretty simple in operation, it just takes button presses and converts them to a standard serial output which I will program girder to respond to.
I will post pictures after I get everything installed in the car, even though you really will not be able to see anything after it's done :D