Hack Swaps Keys for Gang Signs, Everyone Gets In

For many of us, forgetting our keys can be a frustrating experience. But for Binh, it was a repeat offender in his daily life. In the last month alone, he had forgotten his keys five times, leading him to embark on a creative solution: building a gesture-based door unlocker.

The result was an ingenious system that utilizes a NEMA 17 stepper turning a 3D printed bevel gear to actuate the existing deadbolt. This simple yet effective mechanism runs 50 steps to lock or unlock, and when complete, turns off to conserve power and prevent any potential damage to his room.

The software behind this clever hack uses Mediapipe, an ML library that can detect finger movements, accessible via Python. However, gesture recognition proved to be unreliable, so Binh opted for a simpler approach: counting the number of fingers flashed in front of the camera. In this case, the system is running on a Raspberry Pi 5 with a webcam as its image input source.

But what's interesting here is that Binh didn't have his own tools and materials readily available. Instead, he leveraged an existing project that had an ESP32/stepper combo ready to go, making it the quickest option for him. However, this also presented a design constraint: since he was staying in a Hacker Hotel, mounting everything with double-sided tape became necessary.

As one might expect, Binh soon discovered that his new system was not immune to penetration testing. Brute-forcing proved relatively straightforward, so he's now planning on implementing a two-factor authentication (2FA) mechanism to add an extra layer of security. Perhaps a secret knock or a physical token will be used for this purpose.

While using his phone might seem like the most convenient option, Binh wanted something more exciting and memorable. Whatever the second factor turns out to be, it's hoped that it'll be something that can't be easily forgotten in the room.

If this project has piqued your interest, you're in luck! It's open-source on GitHub, allowing you to check it out in action and follow along with the build process. Watch the video embedded below for a closer look at Binh's gesture-based door unlocker in all its glory.

Additional Tips Needed!

We'd like to extend our gratitude to Binh for sharing this fascinating project with us. Now, we turn to you, dear readers of Hackaday: please share your own hacking tips and stories! We're eager to hear about any creative solutions or projects that might inspire others.