After the Foucault pendulum at the Houston Museum of Natural Science stopped working a while back after maintenance on the building, workers set out to determine what was wrong with the mechanism that normally keeps it in motion. Fortunately, it turned out that all they had to do was fiddle with some knobs to get everything dialed back in proper-like.
When we previously covered this dire event, it was claimed that this was a one-off system, hacked together by some random bloke. But as can be seen in the video and further detailed in the comments to the video the reality is far more interesting.
This particular Foucault pendulum is one of many that were created by the California Academy of Sciences, with hundreds of them installed throughout the US and possibly elsewhere. That said, since a pendulum of any description will never be a perpetual motion device, the electromagnet installed near the top of the installation has to carefully add some kinetic energy back that was lost due to friction as the pendulum moves around.
Sadly the video doesn’t go into much detail on what exactly was wrongly configured with this particular pendulum. Keeping a weight at the end of a long cable moving around at a set velocity is a tricky business, so it’s little wonder that getting some parameters wrong would engage and disengage the electromagnets at the wrong times and making the pendulum stop swinging.
Continue reading “Debugging A Stopped Foucault Pendulum’s Electronics”
Generally when a game console with an optical drive stops reading discs the first thing that people do is crank on the potentiometer that controls the power to the laser diode to ramp up its output. While this can be a necessary solution to eke out a bit more life out of a clearly dying laser diode, this can actually massively shorten the lifespan of a good diode that’s just held back by bad capacitors. This is demonstrated by [Skawo] with a 
