Many people ask how to build one. Let me tell you it is not very easy.
The device consists of two parts a D2B audio controller and a Raspberry PI which handles the Bluetooth streaming. The latest version of the unit user Raspberry PI Zero – the regular, not WiFi version.
The two boards connect together via 40 pin header. The D2B unit receives audio via I2S protocol from the Rapsberry PI. The two units also communicate via serial interface. The Raspberry PI is powered by the D2B audio unit. The D2B audio unit also can reset the Raspberry PI board if it is not responding to serial commands.
Here is the schematics of the D2B unit. Jaguar D2B board
The micro-controller is Cypress PSOC4 4100 series. Here is the firmware it is running.
The Gerber files that one can use to make the PCB.
The fiber optic connector is 3D printed. Here are the model files. There are 3models for the 3 parts of the connector. The optical receiver is EAPLRBA0 the transmitter is EAPLTBA0
Instructions how to built the software for the Raspberry PI board.
You would need a micro-sd card for the Raspberry PI and a Bluetooth USB dongle (The ones marked with CSR 4.0 work fine)
I’m very pleased with the new box design. It allows me to play with multiple color plastic, so just in time I created a “4th of July” (red, white and blue) device edition.
I had to re-design the new box. Before I was trying to make it from 2 parts – top and bottom. This process had issues because the bottom part would not 3D Print correctly – it would keep curling up due to stress in the ABS material.
So finally I made the box bottom from several pieces. The bottom has 4 curved corners and 4 side panels, which slide down – you can see one of the side “panels” in this picture.
Also, you can see the size of the old device version compared to the new version.
I was not satisfied with the previous Pi Zero board, because it was larger than the Pi, so here is a new version which has the same size as the Pi Zero.
Here is the new board mounted on top of a Pi Zero:
The spacers are a bit too short – you can see the bolt hitting the HDMI connector.
Here is the final version in a new box:
The Raspberry Pi foundation did something weird, and all Raspberry Pi model A+ disappeared from the market. I could not order anything.
A month later they announced a new board – the Raspberry Pi Zero. It was great except it was also made from unobtanium. I managed to get a grand total of one from an eBay scalper.
Anyhow, I had to design a new version of the CD-changer emulator which worked with the Raspberry Pi Zero because it looked like the days of the A+ model were numbered.
So this is the first board I did, which was just a bit bigger than the Zero itself. On the image, you can see the board in a new box for it. The Pi Zero is MIA.
Also, my SMD soldering skills have improved slightly.