Matrix Hexpansion v1

The original prototype for a matrix hexpansion. Unless you wish to make a prototype with the IS31FL3731 LED driver, you probably want the improved v2 board with more pins (but without the option for a dedicated driver IC).

BOM

• v1 2026-04-22: 1mm, ENIG, purple

Prototype daughter boards

• Big loop (for 3731)
• Subway (for CH32V003)

Notes

• Not tested the 3731 driver.
• I've hand-assembled two of the adapters with the subway daughter board and not all LEDs are working (different ones on each board). Suspect I've shorted some pins during hand soldering.
• The two outer resistors on the back conflict with the standoffs on the badge base board. Recommend not populating them and covering with non-conductive tape or paint.

I will probably provide these boards unpopulated if anyone wants to source their own LED drivers and give them a chance. I think the v2 board has a better pad layout and will be more generally useful going forward. However, I suspect the quality of PWM output will be much better (less flicker, more brightness) with the dedicated driver compared to using the GPIO pins directly.