I was looking for a better category for this post… this was the closest I could come up with.
I am looking for ideas from someone who may have faced a similar problem, and how they solved it.
I build relative dumb controllers for my home or more so property automation; based on some Arduino board and or ESP8266 if wired is not possible… the controllers do what they have to do, but the interfaces, or config is done via openHAB v1.
 My self-inflicted constraint, or shal I say my architecture prescribes that anything is solved with Arduinos, ESPs, wired, WiFi, MQTT.[/edit]
I have a bunch of domestic irrigation controllers, which dies one after the others; hence, I need to build a reliable replacement.
So, a few days ago I started thinking…
Basics: 15 irrigation valves spread over 5 acres.
Not keen on putting wires between controller and valves (wireless it is).
The watering program is simply sequential… OH, triggers one valve after the other via MQTT messages; benefits, the pump stays on until all 15 are done.
The problem is not building something; but figuring out how to control the valves.
No wires means, wireless, but also battery powered.
The ESP chews up at least 70mA in WL mode. Pretty useless approach waiting for one signal to go on and another to off, once per 24h.
Yes, I will have a solar panel charging the LiPo inside; still, the best thing is to put the ESP to sleep.
Once I work with sleep mode, the problem is a different one: direct control.
The thing is a asleep when I send a valve ON command.
Hmm, just had an idea. Use my OH timer to trigger the first valve via MQTT. When the first valve comes on, it gets the message to switch on, plus a time for how long to switch on. Then uses this value to run for X minutes; sends an OFF command back to OH, which then trigers the next valve, and so forth, until all 15 are done. Duration does not play a role.
However, one down side. Because the valves mostly like come on after 0-max sleep time, the pump may have switched off and thus may start up to 15 times per day – aiding its quick demise.
What would you do?