This Fast Palm-Scanning Smart Lock Is No Jedi Mind Trick

Practically speaking, palm vein scanning still has some of the weaknesses of other biometric authentication types like fingerprints or facial recognition, so if your hand is dirty or covered up with a glove, it won’t work. I can live with that, and TCL has seemed to do a good job nailing the tech as well as anyone can right now; the D2 Pro worked reliably throughout testing to unlock my back door (and let me cheesily holler “open sesame” while I did it). If only it didn’t come with certain compromises.

Breezy Installation, Buggy Setup

The boxy-looking D2 Pro isn’t especially attractive or unattractive—although the outer portion has a whiff of Cybertruck vibes when viewed at an angle. The whole unit feels durable and its locking action is smooth. The smart lock is rated IP55, meaning it should be dust-resistant and capable of handling jets of water.

If you’ve ever installed a deadbolt lock, smart or otherwise, the D2 Pro holds no real surprises and only took me around 15 minutes to stick on my door. It’s hard to find compatible door dimensions for the D2 Pro on TCL’s website, so here are the smart lock’s specifications, from its installation instructions:

• Latch bolt circumference: 24mm (0.944 inches)
• Latch bolt length: Adjustable, 60mm (2.36 inches) or 70mm (2.76 inches)
• Cross bore (the big hole through your door): 54mm (2.12 inches)

Setup in the TCL Home app was a little more fraught than physically installing the D2 Pro. My phone connected to the smart lock without issue, and I had no problems configuring its Wi-Fi connection. (While Wi-Fi isn’t necessary for things like palm scanning, it is for app and smart home control—more on that later). But then the app prompted me over and over to update the smart lock’s firmware, seemingly not applying it when I tried.

The D2 Pro also appeared to fail when I tried to register my palm. I say it appeared to, because after I gave up trying, I found the smart lock had registered each of those attempts just fine. Eventually, the firmware updates went through, and I stopped getting error messages during palm-scan registration.

Wave of the Future

The D2 Pro can be unlocked in six different ways. In addition to waving your palm in front of the smart lock, you can unlock it using a number pad, a physical key (it comes with two), a button in the TCL Home app, through Google Home or Amazon Alexa, and using a key card fob that, for now, isn’t included in the box. TCL spokesperson Will Bright told me in an email that the company plans to ship the card with the smart lock later, and that early D2 Pro owners who didn’t get the card can request one by emailing TCL’s home security customer support at [email protected].

The palm vein authentication part of the D2 Pro really is the star of the show. There’s a slight learning curve to properly positioning your hand, which needs to be between 4 and 6 inches in front of the scanner at the top of the smart lock. You’ll know when you’re in the sweet spot because you’ll get the instant gratification of the door unlocking. (TCL says it takes 0.3 seconds to authenticate, which seems about right in my experience.) The D2 Pro won’t work if you’re wearing gloves or your hands are covered in dirt, but it had no problem identifying me when I dunked my hand in water or covered it with a clear plastic sandwich bag.

When you approach the D2 Pro, a doorbell button lights up on the keypad. Tap the pad and more backlighting reveals large, easy-to-tap numbers for code entry and a lock button. TCL doesn’t sell a doorbell chime to go with this smart lock, but its built-in speaker was loud enough by default that I could hear it clearly two rooms away. You’ll tap the lock button after you enter a code to unlock your door, or long-press it to lock the door. I didn’t like the long-press, which takes long enough to work—about three seconds—that I kept wondering if I had missed the button. Unfortunately, you can’t tweak that in the app, so you’re stuck with that long-press unless TCL changes it later.

From the inside, you can lock or unlock the D2 Pro using its standard thumb turn or the button sitting next to it. Above these, a sliding cover hides the D2 Pro’s 10,000mAh removable battery that’s rechargeable via USB-C while in or out of the smart lock, and looks a lot like a small portable power bank. (Did I try charging my iPhone with it? Of course I did. Did it work? No, but that would’ve been fun.)

TCL claims the battery can go for up to 10 months on a charge, and though I didn’t spend that long with the smart lock, after a week of going in and out of my backdoor several times a day, the app still shows a “High” charge. For those with battery anxiety, Bright said the company plans to sell spares on Amazon, as it does for the D1 Pro and D1 Max, starting in September.

The D2 Pro Needs More Smarts

The D2 Pro falls down a bit when you get to the app control part of the equation. The TCL Home app does several things right, like notifying you quickly when your door has been locked or unlocked, or when someone is ringing the doorbell. And you can set a maximum number of failed attempts to unlock the D2 Pro before it stops responding, and for how long it waits to start again. The app also has a robust “Events Summary” page for checking when, how, and how many times it’s been unlocked, and an option to notify you if someone—your child, for instance—hasn’t returned home after a set time and used their code or palm to open the door.

Those are nice features to have, but the TCL Home app doesn’t let you set up a locking schedule or geofenced automation that locks your door when you leave home. The D2 Pro does have an auto-lock feature that you can set to trigger anywhere from 10 to 120 seconds after unlocking the door, but that’s time-based and the smart lock has no apparent ability to detect when the door has been shut, so it can trigger with the door open. It’s better than nothing, but I’d prefer to be able to schedule when auto-lock is active.

You can set up scheduling and other automations if you connect the D2 Pro to Google Home or Alexa—I tried with both and it worked as expected—but for now, there is no support for other smart home platforms. Bright told me that TCL has an Apple Home-specific version of this smart lock coming later, but splitting smart home devices like this up by platform increasingly feels out of step in a time when the Matter standard, which lets devices work with any of the major smart home platforms, is showing up in so many more devices.

Another benefit of Matter is that the standard requires that Matter-connected devices support local software control even without an active internet connection, something that’s not currently possible for the D2 Pro. That’s crucial not just because it lets you control things when your internet goes down, but because it makes smart home devices snappier to use. According to Bright, local control is on TCL’s roadmap but in the short term, the company has “no plan to ensure that the TCL Home app can control the D2 Pro locally in the event of an internet outage.” That said, he added that “all customer information is stored 100% locally for maximum privacy.”

Affordability Wins the Day

If you ignore my quibbles with the TCL D2 Pro’s software and smart home compatibility, this is still a nice smart lock. That’s thanks to its lightning-fast palm-based authentication, which was rock-solid reliable the entire time I tested it, and as someone who is tired of swapping out AA batteries in my existing Aqara U100 and August smart locks, I love the way TCL handled the removable, rechargeable battery. The D2 Pro is also relatively affordable at $189, which is far less than you’d pay for similar alternatives from well-known companies, such as the palm-scanning $399 Eufy Familock S3 Max, a smart lock that also has a built-in video doorbell and Matter compatibility.

The fact that the palm vein-scanning feature of the D2 Pro doesn’t require the internet to work helps the value proposition further—if you just want to be able to wave your hand over your lock like a wizard and have it respond no matter what (assuming its battery is charged), this is one of the cheapest ways to do that. But if you need a smart lock that also integrates with your smart home and you’re already using Google Home or Amazon Alexa, consider how committed to your chosen platform you are; without Matter support, you could be stuck buying a new smart lock down the road, should you decide to switch things up.

Still, TCL has me convinced that any future smart lock I buy must have a palm vein scanner, and one that works as fast as the D2 Pro’s does. Maybe it’s not as compelling as smart locks that use ultra wideband to detect when your smartphone is approaching and unlock your door before you even get to it, but it’s certainly more fun. Now if you’ll excuse me, I need to fulfill my fatherly duty and loudly exclaim “OPEN SESAME” while unlocking my door.