Back from Summer Break: Droid Razr Maxx Car Dock

Summer is long over here in New England, and with snow falling from the sky, naturally my thoughts return back to the machine shop, the electronics lab, and the pile of projects waiting to be completed.

About two years ago, I designed a universal dashboard mounting system for my car.  The basic idea is that the car has a mount permanently installed, and a custom bracket to hold a smartphone plugs into it.  Power is provided through a docking connector.  The mount can be quickly removed and stowed when parking in questionable areas, leaving an inconspicuous dock connector.  The other key element is that when a new phone (or other device) comes along, the removable part can be modified and changed over to work with the new device without having to modify the car.

Back in the Spring I got a new Droid Razr Maxx to replace my old classic first generation Droid.  As before, I bought the stock Motorola car dock with the intent to remove the suction cup mount and attach it to my custom mount.  Summer was predictably busy, and other than modifying that Maxx dock to work temporarily for a motorcycle trip (by attaching a RAM ball mount), it sat unused.  The only modification I made to the original mount was to mill off the protruding fingers on the back, which were used to clamp around the ball of the suction cup arm.

Today, I had a bit of spare time and motivation to tinker in the shop, so I fabricated the necessary adapter out of a scrap chunk of 2024 aluminum.  I didn’t bother designing in CAD or doing any CNC work, but instead just winged it and ran my CNC mill in manual mode and did some pencil-and-paper engineering.  All in all it turned out pretty well, I think.  It’s still a little “industrial” looking in the car and could probably do with a bit of fancier polish, but it works well.  It’s actually considerably more solid than the original one that I created.

I have had a partially abandoned project going on for a couple of years now to make a Bluetooth A2DP audio link, so I could get audio from the smart phone into my car’s aux in jack.  While many commercial products exist for this, I had hoped to put together something which could also connect to the CAN bus in my car and integrate with the steering wheel controls.  However, I gave up waiting to get around to finishing that project, and I picked up a TuneLink device and a 6″ right angle 3.5mm cable, and it actually works pretty well.  Audio quality is decent (for A2DP anyway), and it’s quite usable.   The whole assembly fits quite nicely in my arm rest storage area, which has both the power jack and aux input.

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