Case for Waveshare ESP32-S3-RLCD-4.2

A closed, screw-together enclosure for the Waveshare ESP32-S3-RLCD-4.2 (4.2 inch 400x300 reflective LCD AIoT board), with a separate tilt stand.

There are a couple of open-tray enclosures for this board around, but I wanted one that is closed on every side and that screws into the board's own metal standoffs, so I drew it from scratch. Everything comes from measurements of the real board, not from the vendor drawing alone. The drawing turned out to be about 1 mm off around the active area.

PARTS

RLCD42_back_shell.stl - 1x, 40.5 cm3

RLCD42_front_bezel.stl - 1x, 8.6 cm3

RLCD42_front_bezel_PLA.stl - alternative bezel with a 0.15 mm thinner lip, 8.4 cm3. Print one bezel or the other, not both.

RLCD42_button_cap_x3.stl - print 3, 0.17 cm3 each

RLCD42_stand_22deg.stl - 1x, 16.0 cm3

RLCD42_visos_dalys.3mf - the whole set arranged on plates for Bambu Studio.

Outer size 100.1 x 76.7 x 31.1 mm, depth including the 18650 holder on the back of the board. On the stand it leans back 22 degrees.

FEATURES

Closed on all sides. Openings only where the board needs them: USB-C and microSD on the right, the 2x8 pin header window and speaker slots on the back, three button caps and vents for the on-board microphone and barometer on the top edge.

No screws into plastic. The four screws go into the metal standoffs that are already on the board, so nothing strips out after a few openings.

The bezel does not shade the display: the window is cut to the real screen edge and its inner edge is chamfered 1.5 mm.

Three separate button caps, so you press plastic and not the soldered switch.

Speaker grille: 4 slots 10 x 1.4 mm. The wall behind them is the full 3 mm, with no thinned membrane and no step inside.

The USB-C opening has a collar on the inside that is part of the shell, not a glued-on lump. It leaves 0.5 mm of clearance all round the socket, so tightening the screws cannot pinch it, and the entry is straight down with only the bottom corners rounded, so the board drops in.

The tilt stand clips into a pocket in the back wall and snaps over a 0.6 mm bump on the underside of its tongue, which also pulls the stand up against the case, so nothing rattles. The case also stands upright on its flat bottom without the stand.

HARDWARE

4x M2.5 x 10 cylindrical head screws, head diameter up to 4.2 mm. The counterbores are deep on purpose, 12.6 mm at the bottom pair and 2.0 mm at the top pair, so all four screws are the same length and each has 4 mm of travel before it reaches the board's standoff. Countersunk heads will not sit right: the counterbores are flat and 4.8 mm in diameter. Optional: a 40 x 20 x 2 mm speaker drops into the pocket behind the grille.

PRINTING

0.2 mm layers, 15 percent infill, no supports needed for any part. Back shell open side up, bezel either way (its outer edge is a 0.6 mm chamfer), button caps flange down, stand as it sits in the file.

Two bezels, print one. RLCD42_front_bezel.stl has a lip 0.2 mm thicker than the groove, tuned on PETG, and gives a firm snap. If your printer runs on the wide side, or you print in PLA, take RLCD42_front_bezel_PLA.stl, the same part with the lip 0.15 mm thinner.

The whole set is about 65 cm3 of model volume, roughly 80 g of PLA if printed solid and well under half of that at 15 percent infill.

NOTES

The case is drawn in Python with manifold3d. Every part is verified watertight and a single body, and an automatic check confirms there are no unintended openings.

Not affiliated with Waveshare. Board dimensions from the vendor drawing plus my own measurements of the assembled board.