A fairly quick but above all super practical project that I use every day.
My workshop has 3 locks that are close to the wall. Opening/closing them one by one was a real pain, i had to take the right key one by one, I hit my knuckle against the wall each time.
It was really long and if unfortunately it rained I had time to end up soaked.
And when you realize, snuggled up in your bed at 1 a.m., that you haven’t locked the workshop… 
As I had stepper motors, gt2 loops and esp32 dev boards lying around in a drawer I decided to permanently remedy this problem last March.
I rolled up my sleeves, took out my caliper and started prototyping smart locks under LightBurn:
3 tries were necessary on this shape for a micrometric forced plate insertion in the destination piece:
Pulleys were made thanks to GT2 Gear Generator:
Here are the 2 other locks, based on the same lock model:
On these, the plates are also perfectly adjusted to fit with a small constraint of force and secured with the door by 6 points of Cyanoacrylate glue, so it can be removed easily.
And finally the global view and a zoom on the electronics:
I already manage my entire house under HomeAssistant (Lights, Energy, Heater, Alarm…) so the question of the interface was already solved.
The Esp32 is drived by ESPHome and configured with 2 smart locks. Same locks are pluged in parallel on the esp32, i could have better saved one driver here but i think about it after i finished… Then on HA i have a Lock group that include my 2 smartlocks.
It’s been running perfectly without any faults since March, avg of 3 opening/closing cycles per day. I close each time i leave it to stop my daughters from rushing into the workshop.
Really appreciable reliability for a pure self made project done in 3 evenings !
I trigger the opening and closing by voice, we hear the motors running for 2 seconds and Voila!
For security, no Alexa, homekit, google or cloud speaker here, just a long press on my phone to ask Siri (homebridge/HomeAssistant gateway) to do it.
To open the lock by voice the Iphone must be unlocked.
Locks states are virtual at the moment, esp32 keep it in memory over reboot.
I was planning to add Hall effect sensors on 2 locks for more precision but at the moment virtual state has not failed yet…
