Examples

Omi-derived 3D Print Edition

Works with Nexting · DIY case

Nexting Devices SDK · Case

Omi-derived 3D Print Edition

Build Nexting's 3D-printed adaptation of the Omi open-hardware lineage, flash its firmware, and connect it to the official Nexting App.

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Case study: build the Omi-derived 3D Print Edition

This is Nexting's 3D-printed adaptation of the Omi open-hardware lineage. Nexting redesigned the enclosure geometry, button feel, and clip structure, and wrote firmware for this device. It is not official Omi hardware and does not use Omi firmware.

What makes up this Omi adaptation

Part	Description
Omi open-source project	Provides the enclosure structure and hardware design reference.
Nexting 3D Print Edition	Nexting's modified enclosure, wiring, XIAO firmware, and assembly files.
Nexting Devices SDK	The encrypted BLE/GATT Profiles used between a device and Host.

Download the files

These links are the files needed to build this Omi adaptation. Download the file you need from the public repository.

You need	Public path	Use	Open
3D-printed enclosure	base.stl cover.stl button.stl	The current default three-part enclosure set.	Open enclosure folder
Prebuilt firmware	firmware/pinclaw_zephyr/pinclaw_v2.2.4.uf2	Only for the matching Seeed XIAO nRF52840 Sense path.	Download UF2
Wiring and schematic	docs/SCH_pinclaw_v1.0_diy.pdf	Check soldering, power, and pins; do not wire from photos alone.	Open schematic
Complete instructions	hardware-opensource/README.md	BOM, assembly order, firmware, and license entry point.	Open GitHub guide

Connect to the Nexting App

“Download the files” is the material entry point; this section explains how the finished device enters the Nexting App. The device does not connect directly to Claude Code, Codex, Grok, Cursor, or a cloud Agent. The Nexting App is the trusted Host that manages BLE, device identity, and Agent sessions.

Omi adaptationBLE audio and device stateNexting App (trusted Host)cloud Agent

These two images are rendered directly from the current shipping files: the first is the base.stl enclosure, and the second combines cover.stl and button.stl. Each image maps to the public download path above.

Rendered current shipping 3D-printed enclosure from base.stl — Enclosure: current-version/base.stl

Rendered current shipping cover.stl and button.stl combination — Panel and button: current-version/cover.stl + button.stl

Finish the hardware and firmware
Assemble the Omi adaptation from the public files above and flash pinclaw_v2.2.4.uf2. Test the button, recording, and playback on the bare board first.
Sign in and scan in the App
Open the Nexting App, allow Bluetooth access, and scan for nearby devices. Select the Omi adaptation that matches the advertised name.
Review and authorize
The App reads the model, firmware, and capabilities. Confirm the board is a Seeed XIAO nRF52840 Sense, then complete pairing.
Enter the Agent from the App
After pairing, PTT audio enters the App over BLE and the App forwards it to the cloud Agent. Recording, playback, and the session stay managed in the App.

This product path uses the existing BLE audio protocol. BLE alone does not mean that voice/1, status/1, or another public SDK Profile is already supported. For SDK adaptation, continue to “Connect to the Nexting SDK”.

Assembly and first boot

Assemble in this order: bare board → audio → enclosure → App. Complete each step before moving to the next one.

Connect only the MCU and USB
Power the XIAO nRF52840 Sense and confirm that it enters a UF2 volume, enumerates over serial, and shows a board LED response. Do not attach the speaker or battery yet.
Add PTT and the amplifier
Wire D4, A1/A2/A3 I2S, D6 amplifier enable, 3V3, and GND from the schematic. Power the MAX98357A from 3V3; do not infer the 5V pad from a product photo.
Test recording and playback bare
Verify hold-to-record, release-to-stop, tap-to-play, and LED startup, connection, and recording states before installing the enclosure.
Install the case and button
Dry-fit the printed parts, then secure the board, speaker, and battery. The button must fully release; case pressure must not hold D4 low.
Finish with App pairing
Confirm that the product firmware advertises and establishes audio, then pair through the Nexting App.

Disconnect the battery or USB before service. Do not repeatedly plug a LiPo, power rail, or amplifier while energized. Stop immediately for a smell, unusual heat, or a swollen battery.

Firmware structure

The firmware uses Zephyr. This source map explains each module so you can modify and build it.

Source location	Responsibility	Verification after a change
src/button.c / button.h	D4 press, release, debounce, and tap/hold classification	Record, playback, repeated input, and bounce tests
src/transport.c / transport.h	BLE audio, commands, and heartbeat transport	Service UUIDs, notify order, sequence numbers, reconnect
src/codec.c, mic.c, speaker.c	PDM capture, Opus encoding, and I2S playback	Recording duration, START/DATA/END packets, audible playback
src/device_id.c / storage.c	Persistent device ID and NVS storage	Stable BLE name and ID after reboot
overlay/*.overlay	Board, amplifier, and I2S pin description	Wiring and audio output on the actual board
prj.conf / CMakeLists.txt	Zephyr feature flags and build entry point	Clean build without stale build-directory state

Build the known XIAO product path from sourcebash

# Run from the repository root
export ZEPHYR_TOOLCHAIN_VARIANT=gnuarmemb
export GNUARMEMB_TOOLCHAIN_PATH="$HOME/Library/Arduino15/packages/Seeeduino/tools/arm-none-eabi-gcc/9-2019q4"
export ZEPHYR_BASE="$HOME/ncs/zephyr"

cd hardware-opensource/firmware/pinclaw_zephyr
west build -b xiao_ble/nrf52840/sense . \
  -DDTC_OVERLAY_FILE="$PWD/overlay/xiao_ble_sense_devkitv2-adafruit.overlay" \
  --pristine

# Artifact: build/zephyr/zephyr.uf2

Use the prebuilt UF2 for a quick reproduction and a source build for development. Build with a board and overlay that match XIAO nRF52840 Sense.

Connect to the Nexting SDK

To connect this hardware to the Nexting SDK, add a message adapter and tests. Keep the voice feature, then expose PTT and one status light through the public Profiles.

Adapter task	Device work	Host work	Acceptance evidence
Device identity	Declare model, hardware, firmware, capabilities, and a stable ID	Reject missing fields, incompatible versions, or identity changes	Device Info snapshot before and after reboot
PTT intent	Translate press/release into bounded voice/1 events	Validate session, freshness, and duplicates before invoking the Agent	Hold, release, replay, and disconnect vectors
Status light	Render only bounded Host state; do not infer Agent state	Send full-replacement status/1 and clear it on disconnect	Connected, recording, complete, error, and clear vectors
Battery	Report the agreed battery service or Device Info value	Treat it as a hint, never as authorization	Charging, discharging, low, and absent-battery tests
Update and rollback	Keep a recoverable boot path and version marker	Deliver firmware only to matching hardware	A wrong-target drill that preserves recovery

The device reports physical intent. Agent mapping, policy, credentials, and sessions stay in the trusted Host; device firmware does not store Agent credentials.

Troubleshooting

Symptom	Check	Fix
No UF2 volume appears	Use a data cable, double-tap Reset, and confirm XIAO Sense	Replace the cable or re-enter the bootloader
UF2 appears but the board will not boot	Check the board, bootloader, and overlay match	Rebuild or download the matching UF2
LED works but there is no sound	Check 3V3/GND, A1/A2/A3, D6, amplifier SD, and speaker polarity	Recheck the wiring against the schematic
Recording works but App playback fails	Check START/DATA/END order, sequence numbers, and BLE connection	Fix the audio path before the App path
Product pairs but has no SDK controls	Check Profile declarations and Host enrollment	Complete the Profile adapter and Device Info
Input is duplicated	Check debounce, event IDs, Host deduplication, and disconnect clearing	Implement idempotent handling

When reporting a problem, include the MCU marking, firmware filename, overlay, operating system, USB enumeration result, LED behavior, and reproduction steps.

Two ways to use it

As a voice product

PTT button ↔ XIAO firmware ↔ BLE audio ↔
Nexting App ↔ cloud Agent

Use the Nexting App for recording, playback, and Agent conversations.

As an SDK device

Physical intent ↔ voice/1 · status/1 ↔
encrypted BLE GATT ↔ Nexting Host ↔ Agent

Connect keys, status lights, and battery state through public Profiles.

The voice product uses a BLE audio path; an SDK device uses public Profiles. Firmware or a Host adapter translates button, LED, and battery state into public messages, then the trusted Host connects the device to an Agent.

Flash the firmware

Confirm the MCU first
This UF2 is for the Seeed XIAO nRF52840 Sense. Confirm the board marking and model first.
Keep a recoverable baseline
Confirm that the device boots, records, and plays back, and keep the current firmware file. MultiPad STM32 firmware and other UF2 files do not apply to this XIAO.
Double-tap Reset for the UF2 volume
After a double-tap on the XIAO Reset button, the computer should show a removable disk. Continue only when the volume appears for the expected board.
Drop in pinclaw_v2.2.4.uf2
Download the matching file from firmware/pinclaw_zephyr and drag it onto the UF2 volume. If it does not appear, troubleshoot USB and Reset first.
Verify the product path
Reconnect power and USB, confirm button, audio, LED, and the Nexting App pairing flow, then start SDK Profile work.

This section targets the Seeed XIAO nRF52840 Sense. Other MCUs require their matching firmware and flashing method.

Map hardware to the SDK

Hardware capability	Shipping product path	SDK target	Status
Hold PTT	Start/stop voice capture	voice/1 hold-to-talk intent	Needs Profile adapter and vectors
LED	Local recording/connection feedback	Minimal status/1 state	Declare the light semantics
Battery	Product App battery display	Device Info / battery service	Verify against real advertisement
No screen	No text output	Do not declare text/1; use Host or LED state	A useful design constraint
BLE	Product audio path	Encrypted GATT Profile path	Verify the protocol layer by layer

Start with one PTT event and one status light. Cover hold, release, disconnect, reconnect, and expiry before adding audio, configuration, usage, or custom light effects.

Completion checklist

Stage	Verification	Pass condition
1. Files	Fetch the enclosure, schematic, and v2.2.4 UF2 from the public repo	The linked files are available
2. Product	Complete recording, playback, LED, and pairing on the original path	It works without the SDK adapter
3. Link	Inspect BLE services and confirm identity, direction, and disconnect behavior	Audio characteristics are not mislabeled as SDK Profiles
4. Profile	Verify one PTT → voice/1 and one state → status/1	Messages, replay, expiry, and clearing have vectors
5. Docs	Record the model, firmware, pins, rollback, and limits	Another developer can reproduce the build

Other examples

Case	Why it matters	First deliverable	Status
XIAO reference controller	Fastest SDK proof without enclosure or complex audio	approval/1 + status/1	Ready as the next sample
BLE Ring	Small bandwidth and rotation/click map naturally to physical intent	rotary/1 + keys/1	Needs real hardware specs
MultiPad	Keys, rotary controls, and displays suit extensible mapping	keys/1 + rotary/1 + status/1	Bridge connection planned