---
title: "Enclosures for tiny boards: Seeed XIAO, Adafruit QT Py, ESP32 SuperMini and Feather, 3D printed"
description: "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."
canonical: https://speakcad.com/blog/xiao-teensy-tiny-board-enclosure
published: 2026-09-08
updated: 2026-09-08
publisher: SpeakCAD
---

# 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)

> **Prompt** 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.

## The prompt (Feather stack)

> **Prompt** 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.

## 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](/library/seeed-xiao-esp32c3-keychain-case), the [ESP32-C3 SuperMini case with sensor vents](/library/esp32-c3-supermini-case-bme280-vents) and the [Feather case with a FeatherWing stack](/library/adafruit-feather-case-featherwing-stack) are in the library, pre-filled.

## Prompts to try

- 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. ([open in SpeakCAD](https://app.speakcad.com/signup?next=%2F%3Fprompt%3DA%2520wearable%2520case%2520for%2520a%2520Seeed%2520XIAO%2520nRF52840%2520Sense%252C%2520board%252021%2520x%252017.8%2520mm%252C%2520USB-C%2520on%2520one%2520short%2520edge%252C%2520with%2520a%2520402030%2520LiPo%2520(30%2520x%252020%2520x%25204%2520mm)%2520in%2520a%2520pocket%2520under%2520the%2520board.%25201.5%2520mm%2520walls%252C%25200.3%2520mm%2520clearance%252C%252012%2520mm%2520internal%2520height%2520total.%2520A%25209%2520x%25203.5%2520mm%2520USB-C%2520cutout%2520with%2520a%252012.5%2520x%25207%2520mm%2520outside%2520recess%252C%2520a%25203%2520mm%2520hole%2520in%2520the%2520lid%2520above%2520the%2520LED%252C%2520two%252012%2520x%25202%2520mm%2520slots%2520on%2520the%2520sides%2520for%2520a%252012%2520mm%2520watch%2520strap%252C%2520friction%2520lid.%2520Total%2520size%2520about%252036%2520x%252024%2520x%252015%2520mm.))
- 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. ([open in SpeakCAD](https://app.speakcad.com/signup?next=%2F%3Fprompt%3DA%2520case%2520for%2520an%2520Adafruit%2520Feather%2520with%2520one%2520FeatherWing%2520stacked%2520on%2520top%252C%2520board%252051%2520x%252023%2520mm%2520with%2520four%25202.5%2520mm%2520holes%2520on%2520a%252045.7%2520x%252017.8%2520mm%2520pattern%252C%2520stack%2520height%252020%2520mm.%25203%2520mm%2520standoffs%2520with%25202.2%2520mm%2520pins%252C%25201.6%2520mm%2520walls%252C%25200.5%2520mm%2520clearance%252C%252024%2520mm%2520internal%2520height.%2520USB-C%2520cutout%2520and%2520a%252010%2520x%25206%2520mm%2520JST%2520battery%2520slot%2520on%2520the%2520short%2520edge%252C%2520the%2520lid%2520open%2520above%2520the%2520FeatherWing%252C%2520snap-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. ([open in SpeakCAD](https://app.speakcad.com/signup?next=%2F%3Fprompt%3DA%2520keychain%2520case%2520for%2520an%2520Adafruit%2520QT%2520Py%252C%2520board%252022%2520x%252018%2520mm%252C%2520USB-C%2520on%2520one%2520short%2520edge%2520and%2520a%2520STEMMA%2520QT%2520connector%2520on%2520the%2520other%253A%25201.5%2520mm%2520walls%252C%25200.3%2520mm%2520clearance%252C%25207%2520mm%2520internal%2520height%252C%2520USB-C%2520cutout%2520with%2520an%2520outside%2520plug%2520recess%252C%2520a%25206%2520x%25203%2520mm%2520slot%2520for%2520the%2520STEMMA%2520cable%252C%2520a%25205%2520mm%2520keyring%2520loop%252C%2520snap%2520lid.))

## FAQ

### Can one case serve the XIAO, QT Py and SuperMini?

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.

### Why does my USB-C plug not seat in a thick-walled case?

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.

### Can the case hold a battery?

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.

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