This Smart Lock Is a Wii Bit Flawed

Everything from thermostats to refrigerators and washing machines is getting some intelligence built into it these days. While the wisdom of including these features in certain appliances is definitely questionable, there are also applications where it makes a lot of sense, like a door lock. Why carry around a set of keys when you could unlock your door with the phone that is already always by your side? And of course being able to remotely unlock the door for visitors is also a nice benefit of many of these smart locks.

However, there are security concerns with using a commercial device to control access to your home. Poor design choices or a data breach could have some very serious consequences. For this reason, many technically-inclined individuals will take it upon themselves to roll their own solution. When you are in control of every piece of the system, you are free to make it as secure as you know how.

YouTuber Harrii recently built a very unique smart lock that is all but guaranteed to leave you locked out of your house after a few uses, but it is quite an interesting solution all the same. Harrii used a Wii Remote and a very simple circuit to turn a lock and open up the door when the right combination of buttons is pressed. Unfortunately, it does not unlock the door by turning the controller like a key, but perhaps that will happen in a future update.

Appropriately called the Kii, Harrii’s system relies on just a few components and some existing software libraries for operation, making it a very simple build. An ESP32 development board is connected directly to an SG90 servo, which is connected to a piece of metal that turns a lock to an unlocked position. The Wii Remote interacts with the ESP32 via a wireless Bluetooth connection.

An existing library called ESP32Wiimote handles the connection to the controller, while another library called ESP32Servo drives the servo. With these components in hand, Harrii only needed to write some glue logic to set and check passwords, and also to trigger the servo at the proper time.

This particular build falls under the security through obscurity umbrella. A few key presses on a Wii Remote is not especially secure, however, few bad actors are going to have Wii Remotes at the ready to crack smart locks. To be clear, security through obscurity is a flawed strategy, but that is not to say that more robust security measures could not be built into the Kii by other hackers.

If it seems like using an SG90 is a terrible idea for turning a lock, that’s because it is, which Harrii readily admits. If you don’t want to get locked out, you will either need a beefier servo or a sliding door lock which moves with less force.

While the Wii Remote gives this build a cool factor, you do not want to use this project as is. However, the basic tools and libraries outlined by Harrii could be used to build a secure system. For that reason alone, it is worth checking out this project to see how you can get started building your own smart lock.