Enclosures for tiny boards: Seeed XIAO, Adafruit QT Py, ESP32 SuperMini and Feather, 3D printed
Boards under 25 mm wide need 1.5 mm walls, antenna keep-outs and room for a USB-C plug. Dimensions for XIAO, QT Py, SuperMini and Feather, plus wearable prompts.
The boards
| Board | Outline | USB | Holes | Notes |
|---|---|---|---|---|
| Seeed XIAO (all variants) | 21 x 17.8 mm | USB-C | None | ESP32-C3/S3 have an external antenna connector; nRF52840 has a chip antenna |
| Adafruit QT Py | 22 x 18 mm | USB-C | None | STEMMA QT connector on the far edge |
| ESP32-C3 / S3 SuperMini | 22.5 x 18 mm | USB-C | None | Ceramic antenna at one corner |
| Adafruit Feather | 51 x 23 mm | Micro-B or USB-C | 4 x 2.5 mm on a 45.7 x 17.8 mm pattern | JST battery connector on the short edge |
| Feather + FeatherWing | 51 x 23 mm, stack about 20 mm tall | Same |
The XIAO, QT Py and SuperMini are so close in size that one case design serves all three; only the antenna keep-out and the connector on the far edge change.
Rules for small cases
- Walls 1.5 mm. Enough at this size; 2 mm walls make a 21 mm board look like a 30 mm box.
- Clearance 0.3 mm. Small boards do not need the 0.5 to 1 mm of a Pi.
- USB-C plug recess. The plug overmould is about 12 x 6.5 mm. A 9 x 3.5 mm hole clears the connector; add a 12.5 x 7 mm outside recess so the plug seats.
- Antenna. Leave 3 mm of air at the antenna corner. The AI adds the keep-out when you say which board it is.
- Battery. Many of these boards charge a LiPo. A 402030 cell is 30 x 20 x 4 mm; ask for a cell pocket under the board and the case becomes a wearable.
The prompt (XIAO wearable)
The prompt (Feather stack)
Keychains and clips
"Add a 5 mm keyring loop on one corner" or "a 20 mm spring clip on the back" turns any of these into something you carry. The XIAO ESP32-C3 keychain case, the ESP32-C3 SuperMini case with sensor vents and the Feather case with a FeatherWing stack are in the library, pre-filled.
Prompts to start from
Open one in the builder, change the numbers to yours, and the model renders in seconds. Keep adjusting in the chat before you print.A wearable case for a Seeed XIAO nRF52840 Sense, board 21 x 17.8 mm, USB-C on one short edge, with a 402030 LiPo (30 x 20 x 4 mm) in a pocket under the board. 1.5 mm walls, 0.3 mm clearance, 12 mm internal height total. A 9 x 3.5 mm USB-C cutout with a 12.5 x 7 mm outside recess, a 3 mm hole in the lid above the LED, two 12 x 2 mm slots on the sides for a 12 mm watch strap, friction lid. Total size about 36 x 24 x 15 mm.
A case for an Adafruit Feather with one FeatherWing stacked on top, board 51 x 23 mm with four 2.5 mm holes on a 45.7 x 17.8 mm pattern, stack height 20 mm. 3 mm standoffs with 2.2 mm pins, 1.6 mm walls, 0.5 mm clearance, 24 mm internal height. USB-C cutout and a 10 x 6 mm JST battery slot on the short edge, the lid open above the FeatherWing, snap-fit.
A keychain case for an Adafruit QT Py, board 22 x 18 mm, USB-C on one short edge and a STEMMA QT connector on the other: 1.5 mm walls, 0.3 mm clearance, 7 mm internal height, USB-C cutout with an outside plug recess, a 6 x 3 mm slot for the STEMMA cable, a 5 mm keyring loop, snap lid.
Questions
Nearly. They are all about 22 x 18 mm with USB-C on a short edge. The connector on the far edge (STEMMA QT on the QT Py) and the antenna corner differ, so name the board and the keep-out and slot are placed correctly.
The plug's overmould is wider than the connector. Ask for a 12.5 x 7 mm recess on the outside of the USB hole so the plug body clears the wall.
Yes. Give the cell size (402030 is 30 x 20 x 4 mm, 502030 is 30 x 20 x 5 mm) and ask for a pocket under or beside the board. The AI keeps 1 mm of foam space so the cell is not pinched.