Circuit boards

A project log for NFC Bose Wave Player

An NFC-enabled music player designed for kids to be able to pick their songs, built the hardest way possible

gilphilbertgilphilbert 07/02/2021 at 16:100 Comments

When I decided to use the Bose radio, I hadn't really thought too much about it's shape. Sure, I'd seen these radios in the '90s (not really since then) and I knew it was wedge-shaped, but I guess I didn't really consider what that would mean in terms of PCB shape. Of course the main board isn't square - not even close. This has made PCB design a nightmare.

I generally use EasyEDA - it works on all my devices (even my Chromebook), has a pretty decent feature set and integrates with LCSC's component library. Finally, it can designs straight to JLCPCB who I generally use for my PCBs. Given the shape of the PCB, I really wasn't sure where to start. There's no obvious (0, 0) to use as a corner or central point. I tried taking photos for outlines but the perspective was always wrong. I tried scanning an image in using my flatbed scanner, but that still wasn't quite right.

In the end, I discovered that 150% zoom on my monitor just happens to be 1:1 with real life. This meant I could hold the old board up to my screen and draw an outline / the mounting holes. My arm still hurts from holding it up all that time.

Eventually, I had a rough outline. Printing it off on letter paper at 100% allowed me to cut it out and then it was iterative design from there. Move this mounting hole by 3mm to the left, try again, etc. Finally, I have a PCB shape to work with. Then there's the component placement. The front of the unit only has 12mm clearance, so all the caps, diode bridges, the DAC module (which I will use as-is), etc. all need to go in the back left corner where there's some height. 

Putting all of my components into a schematic gives me this:

After working out the board dimensions and squeezing everything into the top corner:

I'm ordering the boards and any remaining components so I can start building. No doubt there will be several revisions...