Aqara’s U400 smart lock boasts hands-free unlocking

Smart home device maker Aqara is showcasing its new Smart Lock U400 at CES. It is one of the first devices of its kind to combine Apple Home Key technology with an ultra-wideband (UWB) radio to enable hands-free unlocking when an authorized user approaches the door.

Provided you’re wearing your Apple Watch or your iPhone is in your pocket, purse, or backpack, you won’t need to touch the deadbolt to unlock it (compatibility with other smart devices is promised in the future). The trick is made possible by a UWB radio inside the lock, as well as support for Matter-over-Thread, although this also requires you to have a Thread-compatible Matter controller inside your home. For Apple Home Key users, that means an Apple TV or HomePod.

Using its UWB radio, the Aqara U400 measures time of flight (the precise time it takes for a radio signal to travel between the lock and your smart device) and angle of arrival (the direction of that radio signal) to determine your location with centimeter-level accuracy. This ensures that the lock will only open when an authorized user is outside the house and approaches the door and not simply walking past it or when inside the house.

Akara

Aqara claims that this approach provides better security since UWB technology is more resistant to relay attacks than Bluetooth-only proximity systems. A built-in gyroscope allows for automatic locking once the door is closed, helping to prevent homeowners from accidentally leaving their door unlocked. Power comes from a 7.3V rechargeable lithium-ion battery rated for up to six months of use per charge under typical conditions. If the battery runs out, the lock can be temporarily powered via USB-C from a phone or power bank for emergency unlocking.

If you’re not an Apple user, Aqara says it will add support for devices using Samsung Wallet later in the first quarter of 2026. The Aqara Smart Lock U400 also supports tap unlock via near-field communication (NFC, via a smartphone or Aqara keycard), as well as with the lock’s fingerprint scanner; personal codes entered on their PIN pad (including one-off and scheduled access); mobile applications; voice control via Alexa, Google Home, Samsung SmartThings, Siri; or a classic mechanical key.

The Aqara Smart Lock U400 It uses a standard 60/70mm deadbolt and supports door thicknesses from 35mm to 55mm, making it compatible with most US residential doors. The exterior keypad panel has an IP65 dust and water resistance rating, meaning the lock is dustproof and can withstand splashes of water (unless a pressure washer).

The Aqara Smart Lock U400 is available now for $269.99 from Amazon or Aqara’s e-commerce site in silver or black (satin nickel and “shadow” black finishes are also promised).

This news is part of TechHive’s in-depth coverage of the best smart locks.