I have a Claber Hydro 4 irrigation controller that recently stopped working. This system controls 3V solenoid valves that open with a pulse and close with a reverse polarity pulse. The original controller was powered by two AAA batteries and lasted for several months, which was great for my needs.
I’m looking for a DIY or off-the-shelf solution to replace the Hydro 4, ideally one that can still be powered by two AAA batteries or something similar and provides comparable battery life. The new solution also needs to be fairly resistant to humidity as the system is outdoors.
I have some experience with microcontrollers like the ESP32 and would consider using one if it’s feasible to get months of battery life out of it. However, I’m open to any suggestions, whether they involve an ESP32, a different microcontroller, or another type of low-power solution.
So what controller is the Claber using? 3.3v is quite normal for electronics but the difference will come between an SOC and a microcontroller? In essence how do we compare apples to apples?
I guess OP is looking for solution to control it with home assistant…
4ch solenoid control in HA with 2xAA batteries for several months doesn’t exist.
Just to do what existing controller is doing, there is no problem, any low power mcu can do it.
I’m not saying it’s not doable, some low power ble-chip with correct coding could do it easily. But I doubt there is anything ready made for that.
Actually I don’t know: it is closed, with no wifi nor bluetooth. It’s simply an LCD display with 3 buttons to program it, at the desired time it opens the valve for x minutes and then close, I would like to do so without having to rebuild all the system
That would be an extra, I thought about an ESP32 with deep sleep function but it will last around 10 days even with bigger batteries, so it will be a project for the future to when I’ll have an electrical outlet nearby. At the moment I would only like to patch the problem with a diy solution that replicates what the original system do, but I don’t know where to start
Easiest way obviously is to replace it with similar setup you had. Most of irrigation controllers do exactly the same thing with 2-6 AA batteries or 1x 9v battery.
You could do it with esphome devboard combined with solar charge circuit, just with battery it’s not really practical. I know I’m not offering what you would like. No way to wire some power there?
Unfortunately, searching online I saw that most battery-powered controllers are either directly attached to the tap or have higher voltages (at least 9V), so they would not fit. They also have absurd prices (90€ for a solution that I would have to adapt anyway, when with 130€ I buy the whole system new, including solenoid valves and sump).
The most convenient solution, I understand, is to use something with ESPHome or similar. The solution with solar charging wouldn’t be bad but I wouldn’t know where to start, so I’ll try bringing in the power.
The problem with bringing the power in is more of an aesthetic one, having to pull a cable through the garden, plus I’m afraid of water seepage (the sump is watertight), but I think I’ll be able to find a solution for both.
More to the point: searching online I understand that I would only need a relay like this with an ESP32… but how do I get the relay to ‘reverse’ the signal? Making +3V come out is easy, but I don’t understand how to make -3V come out.
Thanks for your patience
You need two relays to swap polarity
But to switch it off you need third relay.
Even better would be H-bridge motor driver module, if you just find one that works at 3.3V.
Here I am, sorry for the delay but I couldn’t work on this these days.
I had an ESP32, a step down and a 4 channel relay at home and I made a circuit to try, on paper it should work but in reality it doesn’t work.
The relays are connected as in your picture: two “negatives” and two “positives,” each with connected to the normally open pole the negative of the 3-volt supply and to the normally closed pole the positive of the 3-volt supply.
The relay is in turn connected to ESP32 with the 6 wires: 4 for relays, GND and 5V.
For now I am manually controlling them, giving a pulse and checking the operation, then I will evaluate whether to manage it with a template switch from HomeAssistant or not.
The point is that it doesn’t work: as soon as I give the pulse on the ESP32 it freezes completely and I have to restart it, also sometimes it gives me the pulse and sometimes it doesn’t, also on the positive I have no problem and even at the other end of the cable I see the 3V, on the negative however (despite giving me the pulse) I don’t see the -3V, can it be because the negative is common between the two?
I’m trying them all a bit, but although trying it on the bench works, once installed I have these problems.
I hope I have explained myself clearly
