Eavesdropping on the Single Wire CAN Bus – Part 3: Bluetooth.

“What a piece of junk!” – Luke Skywalker.

Well, the parts that I ordered (in the previous post) have arrived. For reference, they were the Bluetooth module, the CAN-Bus shield and the cable needed to connect the shield to the car.

I thought I’d start with the Bluetooth module – TEL0108, pictured below. It’s currently powered from a micro-USB cable, although there is a connection point for supplying 5V directly.

Bluetooth Module

I plugged the module in to a set of speakers, and then supplied power. The device powered up which was a good sign (the light came on), but I could have sworn I heard it talking. I turned the speakers up and rebooted the device, and sure enough, it was speaking. There was a heavily accented broken English voice informing me that the device had power and that it was ready to pair – although I admit it took me a few listens to work out the last work was ‘pair’. Once I paired my phone, it then spoke again to indicate that it had connectivity to a Bluetooth device. The code that plays those audio samples would be coded into the IC, which at present is a little beyond my ability to change. Still, from a proof of concept point of view this device will work perfectly. I was able to pair my phone to it, play music through the speakers, and use the buttons to change track and play/pause. I was actually hoping to use this device in the final build, but the fact that I can’t change the Bluetooth device name and the fact that its announcements are so poor, will prevent that.

I’ll use this in the prototype, but when I build the final version I’ll switch to this part instead. The new part, the RN-52, will allow me to change the name of the device (how it appears in a Bluetooth device list); allow me to set a pin number for authentication; and is physically smaller. Again though, the current part will suit the proof of concept perfectly.

The next step is to hook up the CAN-Bus shield to determine if I can capture the signals generated by the car when I use the track change buttons on the steering wheel.

To part 4…

~ Mike

3 thoughts on “Eavesdropping on the Single Wire CAN Bus – Part 3: Bluetooth.

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