A 3-day weekend was the perfect opportunity to kick off the microcontroller-based timer project again. This time I took the time to make a proper circuit board (well, stripboard but at least the wires don't fall out) and proper 3.5mm jacks for all connections so I can set it up more easily.

After much work recreating the timer source code for the microcontroller (and much wasted time looking for the previous code) the inital results were disappointing - it was designed to be accurate (and more importantly repeatable) to a few microseconds - which should mean that the target milk drop would be at the same point every time - but clearly something was wrong as the position was varying by up to 10 cm.

Poring over the sources again I realized the key debouncing was introducing an indeterminate delay - once I took that out I could adjust the position that the drop was captured in a millimeter at a time.

By the time I had it working I was pretty much out of time for taking any pictures, so this was just a quick demo to show my daughter what sort of thing was possible.