Matter PC Switch

Remotely control your PC from any smart home platform that support the Matter and Thread standards (Apple Home, Google Home, Amazon Alexa, Home Assistant, ...).

Features

• Remote power on, shutdown and sleep with ecosystem apps, voice assistants or automation rules
• Power state feedback (the PC appears as an outlet accessory)
• Full local control without a cloud account (depending on your smart home platform)
• Should work with any ATX based motherboard that exposes a front panel power button header
• Fits on a tiny perf-board and is powered directly from the PC (5V RGB header or internal USB)
• Uses Matter-over-Thread

Bill of Materials

Quantity	Part	Notes
1	Arduino Nano Matter
2	PC817 optocoupler	Interfaces power button and power LED
2	1 kΩ resistor	Current limit for LED side of each PC817
1	10 kΩ resistor	Pulldown for power state sensing
1	Perf-board
1	Thread Border Router	Refer to this article for more info
-	Assorted headers and wires	As required

Assembly

1. Flash the Firmware:
   Upload the sketch matter-pc-switch.ino to the Arduino using the Arduino IDE. Flash unique provisioning data after the sketch, see Matter Pairing Codes below.

2. Pair With Your Smart Home Platform:
   On first boot the serial console prints a QR code and manual setup code you can enter in your smart home platform. If the pairing process fails, press the onboard user button to reset the Matter pairing process and try again.

3. Prepare the PC:
   In your OS, configure the power button behavior (shutdown or sleep) depending on your preference. In the BIOS, enable USB/RGB power in sleep/off states when powering the Arduino from an USB or RGB header.

4. Wire the Hardware:
   Follow the schematic below. One optocoupler simulates a power button press, the other senses the motherboard’s power LED so the Arduino always senses whether the PC is on or off.

5. Enjoy Hands-Free Control
   The PC shows up as an outlet accessory named "Computer" in your smart home platform. Control it using voice commands or using the ecosystem apps.

Wiring Schematic

Matter Pairing Codes

The Arduino Nano Matter ships with test provisioning data. All boards therefore per default use the same Matter pairing code 3497-011-2332.

For production use, you should flash unique provisioning data to ensure your Arduino has a unique pairing code. Silicon Labs provides a simple utility for this: Arduino Matter Provision Tool