What You'll Need

Step-by-Step Setup

Separate the two pieces: The CT4 has a main sensor unit and a smaller magnet piece.
Activate battery: Pull the battery tab on the main sensor unit to activate the CR2032 battery.
Open Matter controller: Use Apple Home, Google Home, or another Matter-compatible app.
Add device: Tap "+" to add a new accessory.
Scan Matter code: Locate the QR code on the sensor or packaging.
Complete pairing: Wait for the sensor to connect to your smart home network.
Assign room: Place the sensor in the appropriate room.
Mount the sensor: Apply adhesive tape to the sensor and mount on the door/window frame. Mount the magnet on the moving part (door/window).
Align properly: Ensure the sensor and magnet are aligned and within 15mm of each other when closed.
Test operation: Open and close the door/window to verify detection.

Sensor not pairing: Ensure battery is properly installed. Reset by removing battery for 10 seconds. Try pairing closer to border router.
Status not updating: Check alignment between sensor and magnet. Gap should be less than 15mm when closed.
False open/close alerts: Reposition magnet for better alignment. Ensure adhesive is secure and sensor isn't moving.
Battery drain: Frequent open/close cycles use more battery. Check for drafts causing vibration that might trigger false readings.
Automation not triggering: Verify automation rules in your controller app. Check that sensor shows online status.