Xiaomi just dropped a more affordable smart lock, the Smart Door Lock M40, and it’s nearly identical to its pricier sibling the M40 Pro. The big trade-off? No palm vein recognition. If you can live without that, the M40 still covers the essentials like facial recognition, fingerprint unlock, and remote access. It’s already rolling out in China.
Smart Door Lock M40 keeps facial recognition at a lower cost

Xiaomi’s Smart Door Lock M40 looks a lot like the Pro version launched earlier this month, but costs less by cutting one feature: palm vein scanning. It still packs facial recognition and a fingerprint sensor, so you’re not short on secure access.
A pair of cameras sit up front. The main 3MP lens covers a 175° field to identify people, while a secondary 128° lens watches for packages or movement at your doorstep. Combined, they offer nearly full visibility outside your door.
Xiaomi adds dual cameras and wide-angle coverage
This lock isn’t just smart, it’s watching everything. With its dual camera setup offering up to 190° total coverage, you get solid visibility with person and object detection. The cameras aren’t there just for show, either. They’re part of what makes the facial unlock fast and accurate.
There’s also a 4.98-inch screen inside your home. It shows you exactly who’s outside without opening the door a small but welcome convenience.
Features that make the Smart Door Lock M40 worth considering
If you’re eyeing a smart lock upgrade, here’s what the M40 brings to the table:
- Facial recognition, fingerprint, and passcode unlock
- 4.98-inch display for live monitoring
- Dual cameras with a wide field of view
- Remote access via Xiaomi’s app
- Wi-Fi and Bluetooth support
- Quiet auto-lock with a C-level cylinder
- Battery life around six months on mixed cells
It balances security, convenience, and price, even without the palm scan.
Facial recognition leads Xiaomi’s smart door push
With the M40, Xiaomi’s banking on facial recognition being enough for most people. And they might be right. Palm vein tech sounds cool, but few are asking for it. By skipping that, the company kept the price down without gutting the product’s usefulness.
For buyers who want more smarts at their door without the full Pro cost, this might just be the lock that clicks.

