Add bluetooth audio to a car on the cheap

Bluetooth audio streaming has been around for many years now and every device sold seems to have the capability to stream music and audio wirelessly with high quality from your cellphone or tablet. I decided that I need to step into the times by adding bluetooth to my car and despite buying it only a few years ago it did not have the option from the factory. I bought it second hand so unless it was chosen as an add on option at time of build it can be tricky to add afterwards. At first I looked into adding the factory Audi module but quickly realized that the $400+ price tag was way way out of my price range for a small metal box and some wires.

I already owned a Dension Gateway 100 using that to connect my iPhone to the cars stereo but it has the ability to take a 3.5mm AUX input also. My car has a 3.5mm AUX in along the centre console but I wanted to hide everything under the dash so this was perfect.

After aborting the factory module option I decided that I would look into streaming boxes that simply plugin to existing house hold stereo’s using an AUX input. I have used this kind of device in the past to stream music from my iPhone to a old stereo in my garage so this seemed like a good starting point

No surprise I own another MPOW product and it happens to be the Mpow Streambot Box NFC-Enabled Bluetooth Audio Music Receiver Adapter  and for $32 you can’t go wrong if you are looking to add the ability to stream music to an old stereo. These devices use low 5V DC power that is supplied by a USB wall adapter. Every smart phone comes with one of these and steps your household 120V AC down to the required 5V DC exactly that of a USB port on a computer.  That is great and means you can plug the bluetooth device into an outlet in your home or a USB port on a computer but still not a car.

Screen Shot 2016-02-01 at 12.38.08 PMScreen Shot 2016-02-01 at 11.32.50 AMAutomotive systems are 12V DC so I needed to step the 12 volts down to 5. Enter the “Automotive USB Charger” these little devices take 12V from a cigarette lighter and change it to 5V and usually provide 1AMP of current.  Computers and cars both use DC current so by eliminating the 120V or household AC  I have removed one variable already.

Opening up the USB charger I removed the useless components and soldiered on some wire so I could later tap a ignition source in the car powering the unit on and off with the turn of the key.

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With the 12V to 5V figured out it was on to hardwiring the bluetooth unit and making it all fit together in a tidy package.

Opening up the MPOW I quickly realized there was plenty of space inside to hide the USB charging within its housing.

24387046789_a156c15c5f_z24754696945_e1fb35db03_zWith the housing sorted it was on to powering the bluetooth unit from the USB charger.  With the circuit board removed I could see I was not going to need the USB Port to power the MPOW because there were two hard wire points for battery connection. This meant I was able to cut the end off my usb cable and soldier the cable directly on the bluetooth board bypassing the USB power plug all together.

Not having to use the mini USB plug to power this device meant I could keep all the wiring inside the housing for a clean look.

While this all went fairly easily I forgot now small detail I had overlooked. Sure I figured out the power conversion but forgot that this bluetooth unit shuts off when not in use and requires the press of a button to “wake it up”. I quickly remedied this by soldiering a small wire to bridge the button contacts and because it is a “soft button” and not a physical switch the unit powers on it immediately as if someone is pressing the power button when it is fed 5V. Thank goodness because this whole unit would be buried in the dash of my car with no direct physical access to press a button every time the car turned on.

Before I started to tear this all apart I had paired my phone and tested the unit so it would remember my device each time it was powered on.

It was now time to close it up and see how it was working and I must say everything fit like it was meant to be together. I tapped a ignition source using a fuse tap and this means with the turn of the key the device is powered on then pairs with my phone all while remaining hidden in the car. The 3.5mm aux cable from the MPOW is connected to the Dension unit on the radio and now I can stream a stable signal with hight-fidelity stereo sound to a the car’s radio.


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