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Old 01-09-2017, 09:21 PM  
They call me Garrett
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Join Date: Nov 2010
Location: Detroit, Michigan
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Posts: 4,040

OEM Head Unit w/ Bluetooth

My latest project.

Ever wanted A full Bluetooth radio, but hate the space disco looking aftermarket option? Are you a simple person who just wants their phone hooked up and a radio? Whelp.. I made the solution.

OEM radio with bluetooth audio. For ~ $20 (probably less) in parts I took the tape input and created a straight Bluetooth audio source.

Here is a picture of the bench test before final install:

The Bluetooth streaming was the easy part of this, the hard part was getting a momentary switch that took advantage of the OEM tape control switches to swap between the radio and bluetooth. For this I started out trying to create an SR Latch which is a logic circuit that stores 1 bit of data (on/off). It occurred to me that the cost of a NOR gate IC and Arduino Nano was around the same... and the Arduino, while massively overkill for the project, was perfectly adaptable.

Coded some beep boops and boom, I have an OEM switch swapping the function of the radio.

The next issue I ran into was heat from the 5v regulator. I mounted my board in the deck right where the fat DC motor that was meant to run the tape deck was, which meant OEM venting for cooling and it SHOULD handle it just fine.

Here's a picture of the finished mounting and design:

I'm a bit apprehensive on using hot glue for mounting, but I've done my best to isolate all the circuitry from everything else... big bumps and high freq vibrations SHOULDN'T be an issue.. but.. we'll see.

Here is a video of it all working:

As you can see it works just as the phone would and the phone takes control of fading the sound of the music out if you have GPS going.

It's awesome!

Next goal is to try to flash the controller to make it say "BLUE" instead of "TAPE".

EDIT: 1/10/2017

Left the radio on overnight on my bench. I didn't die in a fire so heat must be alright. For now.

Tossed it in the car but had to change one wire over. I put the Vcc for the Arduino on the battery line that the clock uses to keep itself as a useful clock. Swapped that over to the radio switched 12v and done.

Tuned Detroit - Automotive Blog, check it!

Last edited by equinox92; 01-10-2017 at 04:17 PM..
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