Ten days, one robot, three control loops. How our ESP32 balancing robot on brushed motors learned to stand, to come back after a push, to hold its spot and to drive over Wi-Fi, with the numbers from its logs and the firmware that made it work.
Brushed motors, an ESP32 and an MPU-6500 — and three control loops, each one fixing what the one before couldn't. The angle loop (PID, 500 times a second) keeps it upright, but it rolls 27 cm away. The speed loop brings it back to a 30 cm band. The position loop brings it home within 3 cm — then it drives over Wi-Fi and jumps off a bathroom scale. Three loops, one LQR, or a neural net — which would you bet on?
Four N20 gear motors with encoders and not a single wheel, so I cast my own. One mold printed on a Creality Ender-3 V3 KE: four cavities, four cores, nine M4 bolts, eight funnels and 24 vents of Ø2 mm so the air can get out. The rubber is DEVE DVSIL-P25 platinum silicone mixed 1:1, 20 g + 20 g with a few drops of pigment. Four hours later the red tires came out with a sharp herringbone tread; the black ones overnight. Nine wheels, eight colour combos: which one goes on the robot?
Too much stuff on my desk and no place for any of it — nope. So I designed an organizer in Fusion 360: a paper tray, a round cup, a front cutout and big rounded corners. Then the 3D print, four clear stick-on feet, and everything gets a home: paper in the tray, long things in the cup, clips up front — and the whole thing goes under the monitor. Much better. What on your desk never has a place?
My GM328A component tester worked fine — it just lived glued to a piece of cardboard. So it got a real case: modeled in Fusion 360, 3D printed, supports cleaned off, heat-set inserts pressed in with a soldering iron. Inside is its own power: two 18650 cells in series (2S) with a BMS and USB-C charging on an IP2326 board. Four clear feet, and the cardboard is gone for good. What should get a case next?
A handheld massage roller from three 3D-printed PETG parts: a spiked roller that turns on two 608-2RS bearings around a printed axle, held in the fork of the handle by two M3 screws. With 3MF files and a 3D view of every part.
Tired of USB flash drives being scattered all over my desk, so I designed a custom organizer in Fusion 360 and 3D printed it on my Creality printer.
Designed, 3D printed, and assembled a handheld spiky massage roller from scratch!
