bill z wrote: ↑
Sun Sep 02, 2018 1:14 pm
Thanks for this input!
I like the WIFI Relay Module ESP8266 IOT APP Controller 2-Channel For Smart Home 12V but not sure if it will work with my knowledge of RPIs or Arduinos. Where these are going, there are no cell phone towers around. I did send a message to the seller. Maybe they can offer help.
Back to one of my original questions: because this irrigation system will be many miles away, I would want it to always restart and run without any intervention should the power go out. It would be a problem each RPIs was sitting waiting for a prompt when the power cam back 2 weeks back. How do I set up the OS to start the program on power up with no GUI?
If you lost power for 2 weeks and were relying on a puter system to keep potted plants watered i dont think it would really matter what the puters did when power returned..
The tried n tested stable model is a Pi to host comms this could include providing a wifi ap too but everyone has an old isp router somewhere.
and a subnet of dedicated esp putres to simple tasks such as reading sensors and switching a relay or relays, as each esp is wifi enabled the network establishes itself when configured.
different firmware systems (you can author your own with esp support in the arduino ide, platformio, VS,,etc..) but there are a few very accomplished live projects in existence so you have no need to reinvent the wheel.
whichever esp puters you opt for, Select the best firmware and stick to devices that are supported https://github.com/arendst/Sonoff-Tasmota/wiki
for simplicity just configure each device to react to power outages as you want. just as when your pi will restart and start serving its services on the subnet with power returning each of your esp computers will also restart and carry on as before..
check out utubes and the links above to grasp the scope of these devices, with off the shelf systems like mosquitto mqtt broker and node-red on your pi you have all the glue you need to stick together a custom system. though thats just my preference for system control, there are more options available just check out all the home automation systems out there as what you propose is just a subset of home automation.
**EDIT also esp puters can sleep drawing less power, So battery ups power can be supplied and the puters can be configured for minimal power usage to monitor watering a computer needs to be live for 5 seconds each hour? and perhaps another minute or 2 if watering is needed?