I really interested in this project, i wonder maybe i could use this to send a sensor reading data or for controlling (for example, power plant, micro hydro, plc, etc) from/to remote area. How can i add my own code to work with meshtastic firmware or is there any example (maybe a video) on how to communicate with the node using the api provided since i dont wanna mess with the firmware, let say i wanna use another esp32 as a bridge between plc and meshtastic node. i used to program esp32 using Arduino IDE. This whole procedure seems new to me
Welcome!
These things are very possible with this project and a lot is happening.
Mainly I would focus my attention on the telemetry module (Telemetry Module Settings | Meshtastic) & serial module (Serial Module Settings | Meshtastic) as starting points for your use case.
Connecting to another ESP32 device or raspberrypi may be overkill for your application but is very possible.