So, I have this 4-zone water timer that worked for two seasons, but now the control unit won 't ...

[G+_Matt Koglin]

So, I have this 4-zone water timer that worked for two seasons, but now the control unit won't turn on - and yes, I tried replacing the batteries :)

 

The control unit is powered by two AA batteries in series and is connected to the valve manifold by a 5-wire light-duty cable. It does sort of bewilder me that this ran on a couple of AA batteries for two years before kicking the dust!

 

In any case, I presume the four valves are controlled by a low power solenoid of some sort, and I'm thinking of rigging it to an Arduino or perhaps an ESP8266 and build a little IoT watering system for my yard/garden.

 

A few questions:

 

- Any of you hack a watering timer before? Any advice right out of the gate?

 

- Is it safe to assume the solenoids operate at the same voltage that the batteries provide (3V)? If not, how should I determine the proper voltage and amperage needs for the solenoids to properly operate?

 

- I've got a decent Wifi signal where I want to install it, but grid power would be troublesome. Anybody have experience with how long an ESP8266 will last connected to a small LiPo cell? My Ring doorbell runs for months, so I have to assume it's possible with some basic power management.

 

Thanks!

 

[G+_Matt Koglin]

Here's a quick update:

 

So I opened the control unit. There are four screws on the case which are easily removed. Once the case is removed, there are a number of screws hidden under white silicone. It took some cutting away of the seal with a blade, and a small amount of prying to remove the cover to reveal the electronics.

 

Since it seems like a perfectly good waterproof case that already includes a battery holder, I'm going to attempt to install the ESP2866 in the same case.

 

Once inside there's one screw that holds the logic board to the case. Remove it, the logic board and the LCD display. While it would be cool to get the LCD and joystick controller working with the ESP2866, I'm going to pass on using this interface preferring some sort of web interface, TBD.

 

The connector from the valve manifold has five wires, red, brown, blue, green and white, so to start testing I just wired together 2 AA batteries and started connecting wires. An important note, these low power solenoids must be with pressurized water or they will not work, so I dragged the small rig outside and connected it to the spigot.

 

From my limited research, it appears that the brown wire is a common wire, and each of the other wires represents a valve.

 

Brown: Common

Red: Valve #1

White: Valve #2

Green: Valve #3

Blue: Valve #4

 

To open any valve, apply 3V to the brown line and ground the line of the valve you wish to close. For example, to open valve #1, connect +3V to brown and ground to red.

 

To close the valve, you reverse the polarity. For valve #1, connect +3V to red and ground to brown.

 

For me, one of the valves will not close, but that could be due to age and sitting in the garage for two Colorado winters.

 

Here are a few more pictures, and a more notes/questions :)

 

- I'm pretty sure the current requirements for these solenoids is quite low, although I have not yet tested it. Also I am fairly certain they don't need to be powered to maintain the valve's current position. In other words, once the solenoid is in position it stays there until the polarity is reversed. Once polarity is reverse the solenoid changes position and the power can be disconnected. The solenoid will remain in that state until the polarity is again reversed.

 

- Can I do this kind of polarity switching on an Arduino/ESP2866?

 

 

[G+_Matt Koglin]

[G+_Matt Koglin]