In case you want a potentiometer for a venture, chances are high fairly good that you just’re not going to select up a pencil and draw one. Then once more, should you’re educating somebody how a variable resistor works, that outdated #2 could be simply the factor.
When [HackMakeMod] realized that the graphite in pencil lead is basically the identical factor because the carbon composition materials inside most typical pots, the concept for a DIY educating potentiometer was born. The trick was to construct one thing to securely maintain the strip whereas making contact with the ends, in addition to offering a strategy to wipe a 3rd contact throughout its size. The magic of 3D printing supplied the components for the pot, with a physique that holds a skinny strip of pencil-smeared paper securely round its interior diameter. A shaft carries the wiper, which is only a small size of stripped hookup wire making contact with the paper strip. A clip holds all the pieces firmly in place. The video under reveals the construct course of and the outcomes of testing, which had been truly fairly good.
In fact, the development used right here isn’t meant for something however demonstration functions, however in that function, it performs rather well. It’s good that [HackMakeMod] left the physique open to inspection, so college students can see how the place of the wiper correlates to resistance. It additionally makes it simple to slide new resistance supplies out and in, maybe utilizing totally different lead grades to get totally different values.
Hats off to a intelligent construct that ought to be sure you assist STEM academics interact their college students. Subsequent up on the lesson plan: a homebrew variable capacitor.
Due to [Keith Olson] for the tip.