ESP32-C3 SuperMini + LD2410C case: thick-USB pocket & locking ball mounts

• Thick-USB case: a 12.1 × 6.9 mm pocket in the end wall, so chunky USB-C plugs (up to about 11.5 × 6.3 mm overmold) seat fully. The original slot only fits slim plugs.

• 16 mm ball back: the original flat back with a 16 mm ball on a stiffened neck, so the sensor can be aimed. It slides into the case like the stock back. 

• Locking sockets: the ball snaps in past six springy collet fingers, aims about ±35° plus full rotation, and an M3 clamp screw locks it in place. 

  • wall-socket.stl: two countersunk screw holes 

  • wall-socket-relief.stl: the same wall socket with a built-in cable strain relief. The USB cable weaves right / left / right around three pegs and sits under their half-caps. A third screw sits right beside the pegs, so a yanked cable pulls on the wall plate and screws, not on the sensor. Leave a little slack between the sensor and the pegs. Fits cables about 3–5 mm thick. Mount it upside down if your cable runs up.

  • wall-socket-mini.stl: 32 mm square, no holes, for tape or putty 

  • corner-socket.stl: an inside-corner wedge, tilted 15° down. The clamp screw is underneath, so you can reach it with a 2.5 mm hex key with the unit installed.

• Fit tests: fit-test-gap0.25 / 0.30 / 0.35, the socket on a small disc with the gap engraved underneath. Print these first if your printer runs tight or loose.

• Cable clip: a small stick-on clip to tidy the USB cable.

Fit notes (PETG, 0.4 mm nozzle, 3 walls)

The ball printed at 16.10 mm. With the collet fingers, every gap from 0.25 to 0.35 snaps in easily and is loose until clamped, which is the intent. The smallest gap wins: the clamp slot can only close the cavity by about 0.5 mm, so at 0.35 it barely grips. All the sockets here use 0.25. If yours won't snap in, print the 0.30 test.

Hardware

- 1 × M3×12 socket-head screw + M3 nut per socket (clamp). The nut sits in a trap.

- Wall socket: 2 × countersunk wood or drywall screws (3 for the relief version).

Print settings

PETG (PLA works for everything except the collet fingers, which like PETG's flex). 0.2 mm layers, 3 walls, 15–20 % infill, no supports. Print the parts as oriented in the files. The corner socket lies on one of its wall faces.

Electronics (unchanged from the original)

Snip the LD2410C's OUT pin. VCC goes to 5V on the ESP and the other pins line up: radar TX → GPIO3, RX → GPIO4. The CAD scripts (Python, manifold3d) are in the source zip, so you can change the gap or the USB pocket size.

Credits

Original case, flat back and design: FriedCheese (Printables 582630), CC BY 4.0. This remix is CC BY 4.0 too. Please credit both if you remix it further.

## License

Creative Commons — Attribution 4.0 International (CC BY 4.0)