Homebrew fiber optic loop cable

Very simple homebrew fiber optic “loop” cable. The D2B devices have to form a loop and this little gizmo comes very handy if you have to disconnect a device – just plug the loop in the empty fiber optic socket.

The connector is 3D printed, the optical “cable” is cut from SP-DIF (aka TOSLINK) cable – they use the same 1mm plastic fiber core.

CD-Changer emulator mounted in my car

This is one of the first working prototypes. The box has a Raspberry Pi model A+ which does audio streaming over Bluetooth. I covered the box with copper foil to try an minimize the EMI interference.

Closeup of a D2B optical converted board

This is a small board that sits on the back of a CD-changed for Mercedes-Benz card which use the D2B fiber-optic protocol. The chip is labeled OCC8001-02.

The board has 2 external connectors: one electrical 3 pin (GND, 12V and “wake-up”) and one optical connector. There is internal FPC that goes to the CD-changer.

There is a similar board in the CD-changers used in Jaguar card, but they use different optical plug.

Improvised EEPROM reader

I had this handy board based on the Cypress EZ-USB FX2LP chip. I wanter to read the software that was driving the radio for a 2001 Benz S-Class, so I put this cobbled-up EEPROM reader.

I also build an 8051 CPU emulator to see what the software was doing. Didn’t get much info from it apart from the chip init sequence, because the emulated radio was trying to talk to the security CPU on the front panel and shutting down.

Early D2B protocol hacking

This is a small experimental board I built to connect the optical adapter from a CD-changer to a PC so I can control the D2B protocol chip via i2c.

The board had a flat cable connector to the CD- changer board, a small A2D converter with aux-in, some pins for the I2C protocol and a LDO.

Interesting accident I had was that I used solder flux which converted to zinc-oxide over time and shorted some of the PCB traces. It took me quite a while to figure out why the thing would just stop working.