Solar powered remote controlled dam pump


#1

I’m near the Warrumbungle range, lightly wooded, and our garden irrigation dam is about 400m away. It has a solar panel, a battery, a control unit, and a tiny pump. On remote command from the house network, it pumps every few weeks up to a storage tank above the level of the garden. The tank has a flow sensor and another control unit. The house has a control unit with WiFi to house network. Here’s a system diagram.

We used three Arduino Pro Mini modules from Little Bird Electronics, three Radiometrix BiM1 VHF narrow band FM transceiver modules at 151 MHz, and the Virtual Wire library for Arduino.

The range of the system ended up being about 6km, with omnidirectional antennas, because of the frequency chosen. I was going to switch to directional antennas if necessary. I’d probably use different modules today, and the Virtual Wire library has been abandoned though it still works and there is a different library that can be used.


New Members: Introduce Yourself Here!
#2

@quozl - are any more details coming? What flow/ full/ overflow sensors did you use?


#3

@AndrewHead, sure, lots more details, but was looking for interest first. Good questions, thanks.

  • flow sensor; a hall-effect fluid flow sensor, is wired to pin D2 and used with attachInterrupt pin change interrupts; on the end of the pipe where it reaches the storage tank; actual sensor was a Jaycar one that is no longer listed as far as I can see, but Little Bird has several alternatives, such as the half inch one from Adafruit,

  • full sensor; a side of tank float switch, wired to an input pin, which has proven to be a great place for frogs to take a rest from swimming, hence the …

  • overflow sensor; two bare aluminium bars screwed into a terminal block mounted under the overflow vent; chosen so the sensor lasts a fair while despite occasional electrolysis.

Also, forgot to mention, the purpose of the vent next to the pump is so that static water pressure in the long pipeline can be released during the self-priming phase of pumping. Pump is easily able to self-prime, but only if there’s no pressure on the output. So the sketch opens the vent solenoid valve, starts the pump, waits a few minutes, and then closes the vent. The priming time is a parameter that can be changed from the house.

Electronics for both sites are mounted in the base of a 3m section of 45mm plastic tubing, which contains a ribbon antenna cut and tuned for 151 MHz. Tubing is capped at the top, and strapped to a steel fence post using wire ties. A waterproof vent is made in the top to keep the temperature of the circuit board reasonable in full sun, otherwise the radio performance degrades. Air flow occurs due to chimney effect of solar heating, with no fan required.


#4

Thanks a lot @quozl. I can think of a couple of uses for those flow sensors too. I have a dually redundant electric fire pump setup in which I want to provide periodic automatic checks of the pumps, ensure they are primed, perform a regular flush etc.

You also say “the purpose of the vent next to the pump” - don’t solenoid valves require water pressure to operate?


#5

@AndrewHeard, yes, solenoid valves will open on water pressure, but they will also open on air pressure. Have to install them the right way around for the task. In my setup, the vent valve is on the output side of the pump, before the 300m pipe up to the tank. So the static pressure is from gravity pulling on the water in the pipe is added to any dynamic pressure from the pumping of air or water. The vent valve output drains back to the dam.

(the air vent on top of the plastic tube is a hole with flap of polyimide tape to stop rain entering, so “rain proof” would be a better way to describe it)


#6

How damn clever you are. Thanks for taking the time to explain it all.


New Members: Introduce Yourself Here!
#7

Heh. No, it was adapting to my own shoddy work. The pump was the wrong one for the job, but we’d already committed to it. Electronics inside a plastic pipe in the sun turned out to be a bad recipe as well. :grinning: