How many times do you have to forget your keys before you start hacking on the problem? For [Binh], the answer was 5 in the last month, and his hack was to make a gesture-based door unlocker. Which leads to the amusing image of [Binh] in a hallway throwing gang signs until he is let in.
The system itself is fairly simple in its execution: the existing deadbolt is actuated by a NEMA 17 stepper turning a 3D printed bevel gear. It runs 50 steps to lock or unlock, apparently, then the motor turns off, so it’s power-efficient and won’t burn down [Binh]’s room.
The software is equally simple; mediapipe is an ML library that can already do finger detection and be accessed via Python. Apparently gesture recognition is fairly unreliable, so [Binh] just has it counting the number of fingers flashed right now. In this case, it’s running on a Rasberry Pi 5 with a webcam for image input. The Pi connects via USB serial to an ESP32 that is connected to the stepper driver. [Binh] had another project ready to be taken apart that had the ESP32/stepper combo ready to go so this was the quickest option. As was mounting everything with double-sided tape, but that also plays into a design constraint: it’s not [Binh]’s door.
[Binh] is staying in a Hacker Hotel, and as you might imagine, there’s been more penetration testing on this than you might get elsewhere. It turns out it’s relatively straightforward to brute force (as you might expect, given it is only counting fingers), so [Binh] is planning on implementing some kind of 2FA. Perhaps a secret knock? Of course he could use his phone, but what’s the fun in that?
Whatever the second factor is, hopefully it’s something that cannot be forgotten in the room. If this project tickles your fancy, it’s open source on GitHub, and you can check it out in action and the build process in the video embedded below.
After offering thanks to [Binh] for the tip, the remaining words of this article will be spent requesting that you, the brilliant and learned hackaday audience, provide us with additional tips.
None, because here in Latvia we don’t use doors with latching locks. If I want to go outside I have to lock my doors with a key.
About twenty years ago I simply didn’t lock my doors or my truck, but that has changed. Along with a lot of other stuff. Also my truck has been stolen twice, I replaced my windows three times and defended myself with a firearm once. I don’t think I want my stuff to unlock via gang signs, seems like that is the opposite direction I want my security going.
But re: hacking the problem? I’ve added lots of hidden cut-off switches and ignition kills in my vehicles. Carefully avoiding anything which might be legally construed as a booby trap, because we aren’t South Africa yet (I think lethal car alarms are legal there last time I checked?)
In the “documentary” about modern law enforcement, I think the name of the “documentary” was “Robocop 2”, there was a commercial about “Magnavolt”, no need to lock your doors.
Same where I live, in the Netherlands. Even 5 years ago I often left for work without locking up my house, my car would never be locked. I have three doors on the outside. I once forgot to lock one up for probably 2 years. I didn’t realize it was unlocked.
Crime in the small farmers village where I live is getting out of control, especially the last few months. Bike thefts, cars getting their converters stolen, break-ins, stores getting robbed with guns. It’s so out of control. Even a year ago I didn’t think this would be possible. I have to retrain myself now to lock up my house, lock up my car, lock up my motorcycles. It’s like living in a big city.
Bavaria in South Germany here, 50km from Munich. The flat doors in the house were locked in the night or at absence, the rest was unlocked, except when we were on vacation. Happy old times, up until 2014, when eastern europe “recyclers” took everything metal which was not fixed or locked away, like the locusts.
One year later the torrent of refugees came in, and we often had a complete foreign village running through our village in the night (they were running along the railway tracks, and a power plant utility track diverges from the main track through our village, they often would not recognize the dead end track)
A gang sign would be too little for me, but the idea that my door knows me and lets me in is very good.
Why no multispectral group of cameras, which 3D scan me, my surface looks with visual light, my deeper blood vessel looks with infrared, moles and speckles with UV, and maybe even a retina scan with two high resolution cameras in the door.
I just want it reliable, non breaking, durable.
Well – About Eastern Europ recyclers – its true, it is… but you have to remember that we had your Grand Dads visiting us in the east earlier and they took a lot more than metal. Its all cool now and I’m joking but I felt I had to remind about it
They came then from both east and west and now it is pushing a new Attila from eastern steppes. And we will not stop him with locking our doors… (yes off topic but beware)
It looks like under utilized hardware. I’d some kind of offline voierce recognition, for example using Vosk server, with some phrase as the hey to unlock (not being “open Sesame” of course)
That’s a good one! Let us know if you decide to make it happen; we’d love to see it.
“My voice is my passport”
The real hack is this “Hacker Hotel”. I wish something like this existed when I was younger… sigh…
the handsigns are easily spotted by a bystander or recorded by a hidden camera, you could add adding some eyeblinks (left, right, or both) between the findercounts. That could work both ways, wrong blinks reset te count-to-access proces, perhaps only for the last “entered” digit, that way if someone was nearby you could simulate a very long access code.
Also dynamic codes based on the hour of day could make it harder to abuse recorded sequences.