When most people need to cut quite a few lengths of something, they turn to a miter saw or something similar and get out a tape measure over and over. Norbert Heinz (aka “HomoFaciens” on YouTube), who’s known for making incredible inventions with very basic tools, decided to instead cut lengths of square tubing with a hand saw.
That’s not the end of the story though, as he also came up with an Arduino Uno-based jig that uses rotational motion to measure how long the resulting cut will be. This digital ruler employs an encoder fashioned out of paper, a nail and two IR emitter-detector pairs, and an LCD screen to display results.
In addition to cuts, Heinz’s device can even be used with a drill press to make repeatable holes. Be sure to check out the details on his project page, and in the video below!