Remote Unlocking the Acura Legend Using a BLE micro-controller and a solenoid

Since the time I’ve had the “Red Dragon”, it has had a broken driver’s side door lock. Getting into the car meant I had to unlock the passenger’s side door, and then use the central locking system to unlock all four doors. Not any more.

With this project, I tried to kill two birds with the same stone. I wanted to learn how to write a Flutter app (since I already work with Dart, I was feeling fairly confident) and at the same time come up with a solution to unlock the door remotely.

For this project, I bought the following hardware components:

Bluetooth Low Energy Micro-controller from Adafruit ($25)
A solenoid that can take input from the car battery ($15, from Adafruit)

So the idea was to do the same thing I’ve been doing forever, that is, toggling the central locking system; only this time, the solenoid will do it for me.

board with microcontroller, a power regulator, connectors for the battery and the solenoid.

3D printed case for some minimal weather protection.

I’ll add details of the circuit later, but I basically used this circuit diagram to connect the solenoid.

The Flutter app would run on my iPhone, and as I would walk closer to the car (or within range of the BLE micro-controller), I would connect to the BLE micro-controller and trigger the solenoid.

Here’s a video that shows this in action: