Designing a Custom Bluetooth Upgrade

The prototype board for bluetooth audio and SD card MP3 player.


The circuit to decode J1850 VPW

This is one of the most impressive projects I’ve seen. I barely understand it, but impressive nonetheless

Thanks! It's fun... Has been on my wish list to build along with a handful of other circuits for tuning. This is a good way to get my feet wet though.

My other ideas include a Knock Sensor breakout circuit (could listen to knock on headset, record it, or better calibrate it)

And a narrow to wideband adapter.

18650 battery charger / management (could use as a backup battery). These are SUPER cheap and inside of EVERYTHING but marked up astronomically.

J1850 datalogger (plug it in and it captures PIDs to an SD card). Would be great to troubleshoot intermittent drivetrain issues. I think HP tuners sells something similar but why not make my own.

etc. etc. etc.

I just happened to start with the blue tooth audio stuff.

This forum is the BEST. I've not have been able to build my truck if not for this forum! Excited to share this project. Hopefully I can get it far enough along to cut prototype boards and share them here.

Took a while but finally found pinout for head unit. I'm going to start powering this up with my lab bench...


After a bit more research it appears the head may use E&C Data which is a standardized protocol for audio systems / radios???


May have gotten even luckier. I need to rig up my tape deck and rear audio station to the test bench with the radio. It appears there maybe dedicated control lines for the remote devices.

C2 Radio Pin 11 "Gain Control Signal"
C2 Radio Pin 12 "Remote Audio Return (Rear Seat Audio) - maybe I can patch in there to the AUX lines.
C2 Radio Pin 13 "Radio Control Signal (Rear Seat Audio).

I wonder if this is the same control signal / line for the tape deck? I don't see anything in harness titled "tape deck"


I need controls for
Play, stop, pause, next, previous, ff, & rew

Radio C3 Pin 10-12 provide an aux audio in