FlipBuddy - open source time tracking cube (ESP32)

I kept forgetting to start and stop phone timers, so I made a cube that sits on the desk. Face pointing up is what you’re tracking. Flip to another face (or the stop face) when you switch.

It’s open source: print the shell, wire a cheap board, flash MicroPython, use the free web app if you want history and config. Or run it mostly offline after setup.

I wanted a decent outer surface texture, so the shell is a cube net that folds into place. LED light-guide tolerances are intentionally tight: once you push a guide in, it should stay. Know your printer’s tolerances, or run the test pieces first.

How faces work

The cube is symmetric on purpose. I tried numbers, symbols, textures. None of it felt right. Instead, when you pick it up, move it, or tap it, the LEDs light every face that has an activity, in the color you set in the dashboard. Colors hang for a few seconds then fade. For me green is real work and orange is AI stuff. I don’t care which physical face that is. I care what’s lit and on top.

What’s is included (files)

• Cube net STL (print as one piece; recommended)

• Light guides (transparent filament) ×6

• LED clips ×6

• MPU6050 clip

• Tolerance test pieces so you can dial the printer before the full net

• FreeCAD source in the repo if you want to change things

Print notes

• Clips are meant to rotate into place, not only push straight down

• Light guides: transparent filament

• Rough settings that worked for me: 0.2 mm layers, 3–4 walls, 15–20% infill; a little support under the ESP32 holder cantilever

• eSUN PLA+ printed fine for me; PLA also looked good. Not tested with PETG or other materials yet

• If the fold lines bother you, warm the printed net slightly before folding. Stay below your filament’s glass transition temperature

• Full tips in the assembly PDF

Electronics (nothing fancy)

• ESP32-S3 SuperMini (or similar)

• MPU6050

• 6× WS2812B

• 550 mAh+ 3.7 V LiPo with protection

Software

• Firmware is MicroPython on stock builds (no custom SDK compile)

• Repo (firmware, STLs, PDF): https://github.com/PonderlyRobotics/esp_flipbuddy

• Free dashboard: https://www.flipbuddy.app

License

• Firmware: MIT

• Enclosure / STLs: CC BY-NC-SA 4.0

• If you want to sell the hardware design commercially, talk to me first

Solo project. I’m a cloud person who learned just enough hardware to ship something I actually use. Questions, print photos, and “I changed X” posts are welcome.