Hi.
I am looking for advice on which board may fit my purpose. My intended route as of right now is described at the bottom of this post.
I have a door lock that has an option for bluetooth module. It has 4 pin (V, GND, LOCK, UNLOCK). Pull pins high for 650 ms to lock / unlock. The door lock is powered by 3 x AA batteries.
The bluetooth module is quite useless, it relies on an app and everything is so slow that you may as well manually unlock the door.
While I already have several nRF51822, I understand they are a bit outdated, an a nRF52840 board may be the way to go. The Arduino Nano BLE 33 is interesting as well.
I can't seem to find any boards that can be supplied by 5v in an power efficient way, and I may have to add another 3.3v supply.
What I have in mind
ESP32 - Communicates to smart home systems through MQTT. MQTT message "lock"/"unlock" triggers BLE tx "lock"/"unlock". Saves the last BLE tx to send regular door lock status messages through MQTT.
BLE board - Connected to door lock. Pulls the according pin high for 650 ms as per instructed by ESP32 BLE tx.
I'm still reading up on this, and also trying to decicde the best way to make sure BLE board actually received and processed the transmission. Indicate/Notification.