Static Water Supply Pump

Projects General Guidance
1

Hi all,

Running an Uno R3 with multiple capacitive moisture sensors, along with a humidity and temperature sensor set up already. I have a background in programming, so I shouldn't have to bug about that too much :slight_smile:

So, I've been around the forums, YouTube etc and there's something specific I'd like to ask as most posts/projects refer to solenoid switches and standard water supplies, or when using static supplies are only supplying a trickle to single potted plant.

I am watering a 4sqm raised herb garden on a balcony (in Cambodia where it can get very hot).

Water Head Pressure will be highly variable as quantity drops, so I assume calculating this this will not be particularly beneficial. But I understand there are numerous variables and just in case anyone asks...let me clarify. I am using a 20 litre 'jerry can' at an approx. elevation of 1.5 metres, with water delivered over aprox 4 metres of approx 1cm piping.

I intend to simply punch small holes in an the piping when it reaches the 'garden' and have a gentle spray that will rise around 30cm and, water my herbs.

So, which water pump, (any necessary power, relay modules inputs would be nice) will work for my project?

Look forward to your answers and ultimately posting my own Project Solution in the future!

2

Read this three times and very little makes any sense.

Might be better if you post a diagram of what you intend with some form of flow chart or sequence of events.

3

I am using a 20 litre 'jerry can' at an approx. elevation of 1.5 metres, with water delivered over aprox 4 metres of approx 1cm piping.

Why do you need a pump if the system is gravity fed? Maybe you just need a solenoid valve.

4

If you do need a pump, look at windscreen washer pumps for classic cars.

5

if I understand, your main reservoir is a gerry can.
and you want to spray/mist the plants from about 30CM above them.
the reservoir is 1.5meter above, so the pressure from gravity is not enough to spray or mist.

I would elaborate on PaulRB's post.

if you have elevated water, then you only need a valve.
to get spray or mist, you need a pump
to water the soil for the roots, then drip irrigation.

soft tubing, a solenoid and a cam to pinch the tubing can let it drain, softly.

to get a spray or mist, you need pressure. pressure is based on a few things, not the least of which is the total area of all of the nozzle openings and the output volume and pressure ability of the pump.

if you run your tubing over the plants and let the water drip onto a small surface, the drop will splash.
can we assume that you have 1.2meter of height to the point you want the droplets to spray onto the leaves ?

===================

if you have what we call city water, water that comes from some central place, and that pressure varies during the day, but is about 40 PSI (275kpa ?) at times, then you could use that pressure. it would take some work, but there is a thing called an expansion tank. we use them to equalize water pressure from water heaters. you can use a check valve, so when the city pressure is high, it pressurizes the tank, then when you want, open the valve and that pressure will exchange pressure for flow that can mist from nozzles.

in my mind, the question is if your plants need the spray, or if your plants need water on the roots, or if your plant would be happy with drips on them.

6

Thanks for the replies. That's my issue. There's is no city supply as such. Unless I want to run a 20 metre house from the bathroom!

I'm thinking pump, as opposed to solenoid valve, on the basis that it provides pressure and a stopcock in one.

Bearing in mind that we don't have a home depot type store here to obtain valves and low flow sprinkler heads. Simply pin puntured tubing can feed both roots and tips by changing the angle.

Would the standard 12v pumps available at Arduino stores do the job? Or am I going to have to learn you say "car windscreen washer pump" in Khmer? :o

7

Hi,
The most pumps do not stop flow when they are not running, if there is a head of water then some flow through will occur.

If you are definitely going for a pump, then place it and the tank below the outlet to your plants, that way when the pump stops, water cannot continue to flow to the plants.

Tom.... :slight_smile:

8

TomGeorge:
Hi,
The most pumps do not stop flow when they are not running, if there is a head of water then some flow through will occur.

If you are definitely going for a pump, then place it and the tank below the outlet to your plants, that way when the pump stops, water cannot continue to flow to the plants.

Tom.... :slight_smile:

Thanks Tom, not lifting 20 litres of water is appealing lol. Any pump recommendations?

9

Hi,

google arduino water pumps

Or look for a car window washer pump, sometimes they come with a reservoir as well and are 12V.
You would need some driving circuitry between the Arduino and the motor, as well as a power supply and some noise suppression on the motor.

These pumps are usually available form car wreckers yards and will pump quite a bit of water for their size.

Tom.... :slight_smile:

10

I used a small boat bilge pump once for this purpose. I'm not sure I would recommend it. The bilge pump achieves a good flow rate in large pipes, but not much head (pressure). I guess that is not what it is designed for.

11

Great stuff guys. There's a uni here that supplies bit s n pieces at reasonable prices. I'll have a crack with the regular 12v Arduino pump and go from there.

Thanks all.

12

wiper pump. they are built to create pressure and spray.

lots and lots of options for the 'nozzles' hard pipe, PVC or such, can easily be drilled. a heated needle can put in a hole. let it cool a bit then remove.

if you get a wiper pump, see if you can also get the nozzles. those might give you the rain effect you want.
one in opposite corners, the fan output of those nozzles might cover for you.

larger tubing, more holes and the pressure will not be so much that it would spray out . tie a rag over a hole and the rag will get wet and drip and not shoot out.

most pumps you buy for use with Arduino are not going to have power to spray, they are usually only for lifting water about a half meter, the higher, the less flow. over a meter or two and there will be no flow. that is called head pressure. you need an impellor with tight tollerances to get much height.

13

dave-in-nj:
wiper pump. they are built to create pressure and spray.

most pumps you buy for use with Arduino are not going to have power to spray, they are usually only for lifting water about a half meter,

Perfect, thanks Dave. There's plenty of cut n shut shops in Phnom Penh (nothing you'd call a breakers yard!) I'll nose about...

14

I have a couple of observations Robs23, and a suggestion too.

You haven't clearly defined either what you want to achieve, how you intend to achieve it, nor painted a picture detailed enough to eliminate much of the ambiguity in the minds of the readers.

My assumptions arethat you want to:-

  1. Water your herbs to promote their health.
  2. Use as little water as possible to do this.
  3. Automate some or all of the process.
  4. You have already formulated your strategy for watering the herbs (the when and how much).
  5. Your herb garden is outside!

You have stated that the project will be in Cambodia, that it gets hot there, and that the town water supply is either low pressure or sporadic. Later you have indicated that the reason you are using a Jerry can reservoir is because you have no water supply to the watering site, and that the procurement of the general DIY materials is not convenient. Good, a clearer picture is emerging.

I am not clear on whether the mist spray you will generate will be enclosed or open to atmosphere. Clearly if open to atmosphere much of the spray will be lost to the environment and evapouration when compared to plants enclosed in a cloche or similar. These losses will have to be made up by you lugging extra from the bathroom - so again I assume you will take steps to 'consume' as little water as possible to keep your plants healthy.

So to my suggestions:

  1. A mist spray will use much more water than a roots fed drip. Can you achieve plant health with just roots watering?
  2. 'It gets very hot in Cambodia'. If the Jerry can gets warmed there will be an increase in Legionella bacteria. Creating a spray is one of the best ways to distribute those nasty little bugs deep into the lungs of yourself and your neighbours, so consider this if your neighbours are close, elderly, or both.
    ie enclose the misted area if possible.
  3. Consider metering the water discharge if you can. There are several turbine type small flowmeters available via Ebay, AliExpress, or similar. Accumulating data on the water consumption can help in both reducing the water used (=number of jerry can refills), and help you to develop an alarm system to warn of low water level; or indeed a 'holiday' mode, to reduce consumption to an absolute minimum whilst you're away.
  4. As mentioned in a previous post, an old car windscreen washer pump would seem ideal for the quantities of water I imagine you'll use for a 4m2 herb garden. Again I agree that the jerry can should be lower than the sprays to prevent flow when the pump is off, but the pump itself should be lower than the jerry can 'empty' level, to prevent pump cavitation and encourage self priming.
  5. As for hardware, how about a 12v car battery for power, switched through a relay module of the sort available through the Arduino shop, Ebay, etc.
  6. Consider the use of a particle strainer upstream of the pump.

I look forward to reading about your final design and its advantages/problems you overcame.

GM

15

I think people who start out to automate follow a process.
First do it manually. Get an idea of the repetition and figure that there should be aan easier way.
Generalize that some parts can be done easily.
Assume yes assume that mimicking human actions is best. Then set out on that path.
Make it work well enough.

In this case i assume the OP will have a display and menu to show operations And allow changes.
Change duration is the first thing that comes to mind

If that works well enough.
Then that is tthe End of the project.

16

robs23:
Thanks for the replies. That's my issue. There's is no city supply as such. Unless I want to run a 20 metre house from the bathroom!

I'm thinking pump, as opposed to solenoid valve, on the basis that it provides pressure and a stopcock in one.

Bearing in mind that we don't have a home depot type store here to obtain valves and low flow sprinkler heads. Simply pin puntured tubing can feed both roots and tips by changing the angle.

Would the standard 12v pumps available at Arduino stores do the job? Or am I going to have to learn you say "car windscreen washer pump" in Khmer? :o

Without municipal water supply, your biggest problem will be filtering your water so the punctured tubing is not plugged with stuff in the water.

Paul

17

Paul_KD7HB:
Without municipal water supply, your biggest problem will be filtering your water so the punctured tubing is not plugged with stuff in the water.

Paul

Tee shirt over the lid
Filter out particulate and keep out insects.

18

dave-in-nj:
Tee shirt over the lid
Filter out particulate and keep out insects.

My experience is the stuff that grows in the water, not stuff you can see floating on the water. Algae will pass though a t-shirt and bacteria love warm water. They all make clumps which will plug the water ports. Drip water systems use in-line filters that must be replaced when plugged.

Paul

19

Glorymill:
5. As for hardware, how about a 12v car battery for power, switched through a relay module of the sort available through the Arduino shop, Ebay, etc.
6. Consider the use of a particle strainer upstream of the pump.

I look forward to reading about your final design and its advantages/problems you overcame.

GM

I won't be 'misting' so much as 'raining'. Think sprinkler rather than mister nozzle.

Thought of a car battery, but then a charger etc is a pain, and import tax on Amazon etc can run as high as 80%!. I can extend a 12v dc line no prob as it will travel all of 2 (estimate) metres. And of course a relay. I've already decided on a little cheesecloth/zip tie etc at the pipe tip.

I'm going to check what pumps are available. And if I am stuck with a duff arduino driven model, drip will be the only way to go.

Thanks!

20

dave-in-nj:
Tee shirt over the lid
Filter out particulate and keep out insects.

Have running water...it's just that the nearest outlet to my balcony is 15 metres away!
As for bugs and bacteria..we've got dengue and malaria and all sorts of unimaginable ways to get sick here lol