Old 3D printer becomes new Arduino UNO Q-controlled pen plotter — May 19th, 2026 Pen plotters used to be very common in the engineering world, as they were economical for “printing” large technical drawings. They’re still around, but digital-only workflows and alternative printing methods have reduced their presence. But Elliot Madsen is an engineering student fascinated by his discipline’s history, so he constructed his own pen plotter using an Arduino ®  UNO ™  Q board and parts from an old 3D printer. A pen plotter is just a machine that moves a pen around, relative to the paper, in the X and Y axes (plus lifting in Z). That’s why they were ideal for technical drawings that tend to be large and composed entirely of lines. That kind of motion system also closely matches that of an FFF/FDM 3D printer, which is why Madsen was able to build his pen plotter using parts — like stepper motors, aluminum extrusion, and pulleys — from a 3D printer.…