The issues

A project log for Numican

A numitron clock in an altoids can!

riktwriktw 11/13/2016 at 21:260 Comments

This project functions mostly at the time of typing. A few problems have been found which I will try to address in the next version.

  1. The internal oscillator is crap. This is the biggest issue and easily solved by adding an external crystal. The internal RC is better then most as it can do USB without an external oscillator but for a clock it's not good enough unless a minute per day is accurate enough for you. With a 10 cent external oscillator this is reduces to a minute per month.
  2. The 2 numitrons for the hours are slightly differently spaced from the 2 minute numitrons. When you start noticing it it's annoying.
  3. The numitrons have to be twisted a bit when inserted in the PCB for soldering.