The T1N Smart Lock is an open source Matter over Thread device designed for the 2005 Dodge Sprinter 2500 (T1N chassis). It adds what the van never had: lock and unlock from your iPhone, lock state you can see at a glance, and a sensor for any door left ajar. It does this without driving the lock motors directly or replacing the factory module. The factory keys and key fob keep working exactly as before.
The factory service manual identifies the wires, but does not describe reading the lock-state LEDs, using the central timer module (CTM) rail to tell when the van is asleep, or pulsing the locks once or twice depending on state. That approach is the idea behind this project. Every signal and timing it depends on was worked out by hand, with a multimeter at the back of the master door lock switch and a long stretch of testing in the van. The manual gives you the pinout; it does not give you the design.
This device reports observed reality, not commanded state. So your app reflects what the van actually did, not just what it was told to do.
Click to watch a short demo: opening/closing driver door, then locking and unlocking, with the master lock switch LEDs and Apple Home following each change.
It is built primarily for offgrid and vanlife use. It can run from either the van's starter battery or a house/leisure battery; see INSTALL.md for the tradeoffs. It tolerates a noisy electrical environment including engine-on conditions, and is a low-power Matter device so the power budget stays small. It is local-first: it pairs and operates over Thread directly from an iPhone 15 Pro or newer model featuring a Thread radio, and also works through any compatible Thread Border Router for use in Apple Home, Home Assistant, Google Home, or Alexa.
The board is a small carrier for a Seeed Studio XIAO ESP32-C6, which provides the Thread radio and runs the firmware. A transistor pulses the factory master lock line, two optocouplers read the center console switch LEDs without loading them, and a comparator turns the CTM sense line into clean edges for sleep detection. The only connection to the van is five wires tapped at the back of the master door lock switch, landed on the board's five-position terminal block.
In your Matter app the device appears as a door lock plus two contact sensors, one for the driver side and one for the passenger, cargo, and rear doors. For the full architecture see FIRMWARE.md.
The same lock in Apple Home and Home Assistant. Matter is multi-admin, so it pairs to more than one ecosystem at once (see Commission the device).
Everything is in docs/. A typical path is to read SAFETY
first, build the board and enclosure, flash the firmware, then
commission and install it in the van.
| Document | What's in it |
|---|---|
| FIRMWARE.md | firmware architecture and behavior |
| HARDWARE.md | PCB design, BOM, and ordering |
| ENCLOSURE.md | 3D printed enclosure |
| BUILDING.md | building and flashing the firmware |
| INSTALL.md | commissioning and van installation |
| SAFETY.md | electrical and operational safety |
| CERTIFICATION.md | Matter/Thread certification status |
| CONTRIBUTING.md | how to contribute |
| LICENSING.md | license terms |
| Path | Contents |
|---|---|
firmware/ |
C++ application on ESP-IDF (C/C++), source in main/ |
hardware/ |
KiCad project, schematic, and gerbers |
enclosure/ |
3D printed enclosure model files |
docs/ |
all project documentation |
This is v1.0 of a personal project, developed and tested by a single maintainer. It is an uncertified Matter device that uses public test credentials, which is normal for a self-built device and explained in CERTIFICATION.md. Response times on issues vary.
The firmware was developed and verified against one vehicle. Compatibility with any other year, market, or trim is unconfirmed. If you run it on a different T1N, a compatibility report is welcome. The list below will grow as verified reports come in.
| Vehicle | Market | Status | Notes |
|---|---|---|---|
| 2005 Dodge Sprinter 2500 | North America | Verified | Reference build |
Firmware, PCB, and enclosure version history, and which revisions are validated to work together, are recorded in CHANGELOG.md.
Installing this device modifies your vehicle's electrical system and interfaces with the factory locking system. Wiring errors can damage the CTM or the board. Read SAFETY.md before building or installing anything.
| Project | What it is |
|---|---|
| shelly-1-gen4-matter-thread | open source Matter over Thread firmware for the Shelly 1 Gen4 |
This repository is multi-licensed. The firmware in firmware/ is
Apache 2.0. The hardware in hardware/ and the
enclosure in enclosure/ are both CC BY 4.0
(hardware, enclosure).
Both are open source. Use,
modification, sharing, and commercial use are all allowed, with
attribution. See LICENSING.md for the plain
language version.