Some things I'd do differently next time:

  • Include a programming header for the ATtiny85. I had to solder it some 30 awg wire-wrap wire to existing PCB pads to program the ATtiny before adding any other components.
  • Use regular 0603 resistors instead of a resistor network. I ended up ordering the wrong size network and had to use discrete resistors anyway.
  • Show non-integer voltages by adjusting the relative brightness of adjacent LEDs.
  • Indicate voltages above 12V or below 3V by flashing the 12V / 3V LEDs.
  • Make it even smaller by using 0.8mm thick PCBs instead of 1.6mm.