RE: Tempus Fugit... Part 4: micro:bit 5V SPI

genebren — Sat, 28 Jul 2018 14:49:59 GMT

Nice update on your alarm clock blog series. Heat, but no smoke, is much better than instant smoke.

Gene

RE: Tempus Fugit... Part 4: micro:bit 5V SPI

jc2048 — Sat, 28 Jul 2018 09:17:54 GMT

Your circuit has 4 resistors for each channel. 12 in total. Your board only has 9.

I think you've might have missed off the base resistor for the first transistor. That would explain the micro:bit being unhappy about driving it.

It's easily done when wiring a board like this. One method I used to use, with complicated prototypes, was to tick each component and each wire off on a copy of the schematic as they went onto the board.