I wonder whether there is any established protocol for 433 MHz communication, that could be used for self-made devices.
Am looking for something that has the following properties
- well documented
- easy openhab integration
- sensor mesh support (ad-hoc networking, routing)
- low power functionality (e. g. something like scheduled transmission and time synchronization to fully power down the wireless transmitter and receiver)
- optional support for security/authenticity or even encryption
- code available for PIC microcontrollers
- optional plus would be if there would be some interoperability with a RS485-base wired communication as alternative to 433MHz.
Even in case you have something in mind, that does not satisfy all those “constraints” please give me some pointers (if they are beyond google).
I’d like to put some battery powered sensors (soil moisture, temperature, water level, maybe more) around the garden over longer distances and connect them to my openhab instance. As I didn’t find suitable devices on the market I think of creating something on my own, but even with some experience in capacitive sensing, microcontroller programming and electronics, I fear it will fail due to loss-of-interest-before-finishing, if I cannot build on top of at least some communication.