BLE window sensor for Homeassistant

BLE window/door sensor built around the u-blox NORA-B226 (nRF54L10). Broadcasts open/closed/tilt state via BTHome v2 non-connectable advertising. MCUboot OTA-capable.

Hardware

• MCU: nRF54L10 (Cortex-M33, 1 MiB RRAM, 192 KB RAM) in u-blox NORA-B226-00B module
• Sensor: TMAG5273 3D Hall-effect sensor for contactless magnet detection
• Power: CR14250 (½AA) lithium cell, target multi-year battery life
• Enclosure: 3D-printed case with magnet holder (FreeCAD, case/)

Firmware

Rust + Embassy async runtime, BLE via nrf-sdc + trouble-host.

• Non-connectable BTHome v2 advertising (open / closed / tilt)
• MCUboot bootloader with ed25519-signed OTA images
• Host-side unit tests for classifier and gesture logic

Repository Structure

Path	Description
*.kicad_*	KiCad 10 schematic, PCB, and project files
lib/	Local symbol/footprint libraries and 3D models
firmware/	Rust firmware (Embassy, BLE, MCUboot support)
firmware/mcuboot/	MCUboot config and partition overlay
case/	FreeCAD enclosure design and 3MF exports
scripts/	BLE scanner and dev utilities
sim/	Magnetic simulation data

Building

# Install toolchain
rustup target add thumbv8m.main-none-eabihf
cargo install just cargo-binutils

# Build, lint, test
just ci

# Flash (requires probe-rs + debug probe)
just run

License

Dual-licensed: hardware under CERN-OHL-W-2.0, firmware under Apache-2.0. See LICENSE.

AISLER discount

In case you want to build this (or any other) project at AISLER, here's a 10€ discount code for you: MakeInEurope-ZDCTN.