The Infrared Security Protocol
The Apple Watch utilizes a security protocol known as “Wrist Detection.” By default, the watch uses the infrared sensors on its back casing to continuously verify that it is physically touching your skin. If you take the watch off and place it on a desk, the sensors detect the break in contact and instantly lock the device, requiring a passcode to unlock it again. While this is the fundamental security mechanism of the watch (and is required for Apple Pay), for specific users—such as individuals with heavy wrist tattoos that block the infrared light, or users who wear the watch over a thick jacket sleeve—Wrist Detection causes the watch to constantly and erroneously lock itself every five seconds. If you prioritize continuous operation over physical security, you must paralyze this sensor array.
How to Disable Wrist Detection Globally
You can permanently sever the infrared locking daemon via the Passcode settings.
- Open the Settings app directly on your Apple Watch (the grey gear icon).
- Scroll down the main list and tap on Passcode.
- Scroll down to the very bottom of the menu.
- Locate the master toggle switch labeled Wrist Detection.
- Toggle this switch to the Off position, and confirm the massive security warning that appears.
Absolute Operational Persistence
The change is instantaneous. The Apple Watch will completely terminate the background cron job responsible for polling the infrared sensors for skin contact. The operating system is now completely decoupled from its physical proximity to your body. You can take the watch off, throw it on a table, or strap it to the outside of a heavy winter coat, and it will remain permanently unlocked and operational. Warning: Because the watch can no longer verify it is on your wrist, disabling this feature permanently disables Apple Pay, prevents the watch from unlocking your Mac, and disables the Background Heart Rate measurements, as the operating system will not risk executing secure operations without physiological verification.