Automated rain barrel watering system   Swapping coins cells for
capacitors for noise filtering  Here’s an interesting idea:
replace a disposable coin cell battery with a capacitor in order
to filter the noise from an external power supply. [David Cook]
is taking advantage of the falling costs of digital calipers.
He’s mounted one on his milling machine but noticed that with an
external power supply the readings would sometimes reset in the
middle of his work. The LR44 cell he’s replacing makes for very
difficult in-place soldering so instead of permanently replacing
it he built an insert that matched the form factor. The outer
ring is from a piece of copper tubing and soldered to a PCB that
he etched.  If [David's] name sounds familiar it’s because we
featured his Happy Meal toy scavenging a while back.  [Thanks
Thomas]  Beginner concepts: LPT instead of uC  We see it all the
time, a post based on an Arduino board with multiple comments
calling it overkill. How exactly should you control your
homemade periph