Car Stereo / iPod Control System

This project has been completed, but also suspended indefinitely. What I mean by that is I finished the project and it worked great in my car, but then I got a new car which the system is not compatible with. I still thought that it was worth posting a page about it though as it was a neat system and is relatively easy to build if you have a car that it will work in.

To start off with I had a 2005 Dodge Neon which has a pretty standard AM/FM CD playing radio. For a while I had an FM adapter for my iPod, but it just didn’t sound great driving around Saint Louis. The problem was that in one area a certain frequency was perfect, but then when I drove for about 10 minutes that station became noisy and I had to use about 4 different FM stations to get clear music. I got tired of this relatively quickly and found a product to correct this problem. The product I found was a wiring harness and circuit that connected to the CD changer port in the back of my stereo and provided me with an auxiliary (RCA) input to the stereo. (If you want a better picture of what this device was search google for CHRY02-AUX.) Basically this unit emulated a 6-disc changer and sent a signal from my iPod headphone jack to the stereo, thus solving my FM problems.

For a while this system worked great for me and the sound quality was always nearly perfect. However the more I used my iPod in my car the more I wished I had a better way to control songs and playlists. Originally I just had the iPod in a cupholder in the car and it was hard and somewhat dangerous to reach do and search for it while driving and then take my eyes off the road to change the song or playlist. I rarely did this and sometimes got annoyed with songs I forgot I had on my iPod from time to time. Thinking it would be and easy solution to the problem I bought a mounting bracket for my iPod which moved it up onto my dash near my line of sight. I was partially correct as this solved the problem of looking around for the iPod and changing tracks. The problem was still however that I could not change playlists or seek out a certain song or artist easily. That idea got me thinking and while I was wandering at an electronics store here in Saint Louis called Gateway Electronics I found something that sparked my interest in building an iPod control system.

The part that I found is called the Pod Breakout board. What this board does it takes the connector on the bottom of an iPod or iPhone and breaks those 30 pins out to pads on a breakout board that you can easily solder to. Each of these pins has a different function allowing you to communication with the iPod and also receive audio channels. I had seen this board before in projects on various websites and thought I’d give it a try and see what I could come up with.

My original ideas centered around the Arduino I already had and some random control scenarios I had running through my head. My first thought was centered around expansion plans. I say expansion plans because I figured the Arduino I had could ultimately do way more than just control my iPod, which is true. The problem however was that my original idea was to use a Playstation 2 controller I had lying around to control everything. This seemed like a great idea at first to have a game control activating various things in my car, but then reality hit me. Using a Playstation 2 controller is something that is best done with two hands. I forgot that I would probably be driving while using this system and driving without hands is not even an option.

I bounced around other ideas from there by scrolling through Sparkfun’s inventory looking for usable button pads or keypads and never came up with anything that seemed to have enough usable buttons for all the functions an iPod is capable of. I wanted to be able to skip tracks (forward and backward), play / pause, scroll lists (up and down), go back (the menu button on an iPod), and select things (the center button on an iPod). I started to give up on the project when one day I came across the site of David Findlay and found this post. David had the same idea as I had and built a system and coded it on an Arduino. He had also found the perfect controller which allowed me to use every button I was hoping to use, the Wii Nunchuck controller.

Now that I knew what I needed and had found a nice area in my car to hide the circuit I placed an order with Sparkfun. As size was a concern I ordered an Arduino Pro Mini to replace my full sized Arduino. I also ordered a Wii Nunchuck breakout board, and a logic level converter to take the 5V logic the Arduino was outputting and convert it to 3V for the iPod. Once all these parts arrived I drew up a wiring diagram according to David’s images and a reference sheet for my Pod Breakout board, make sure to read about the different versions of the Pod Breakout board as they have different pin outs. After correcting the pins for my version of the Pod Breakout board I came up with this diagram.

Following that wiring diagram I soldered everything together and programmed it with David’s code (I modified the tilt value some to make the menu function less sensitive). After that circuit was complete and programmed I wired the audio out lines from the Pod Breakout board to RCA connectors which were connected to the car stereo adapter I had already purchased. From there all I had to do was solder the voltage and ground wires to the proper Arduino pins to supply the system with power. To do this I tapped into the 12V and ground lines of the stereo adapter so that the whole system was self contained.

This system worked quite well for the time that I had it in my car and was simple with the Wii Nunchuck to have both hands on the wheel while also adjusting playlists and songs. I may revisit the system at some point in the future, but as I’ve mention I have a new car and the system needs to be redesigned to work with it properly.

For a few more pictures of the system and the full resolution of the wiring diagram visit my Flickr Photo Set here.