Automating watering a nursery

Projects General Guidance
1

I am trying to find the most feasible method to wire up a few dozen dc pumps to water the smaller plants at a friend's nursery. I have experience setting up a raspberry pi + arduino nano + moisture sensor + 12v dc pump I use to water my bonzai tree but the pump itself is wired through a relay to a power adapter. I am unsure on how to configure multiple pumps without the need of pluging each one into an outlet. I assume I can use a GPIO expander for more analog connectors for each of the moisture sensors but individual outlet per pump eludes me.

I've considered drip irrigation with controlled pump but some of the plants are tropical/exotic and require different care so homogeneous watering isn't a big contender.

Is there a single power source I can connect multiple 12v dc wires to? Is the only option to mod a computer power supply?

I plan to have multiple raspberry pis per zone and 5v power supplies for the moisture sensor but is there anything I should be aware of when configuring 8-12 moisture sensors per pi?

I'm a programmer so I have no issue with the coding side but the electric portion is all new for me.

2

sennon:
Is there a single power source I can connect multiple 12v dc wires to? Is the only option to mod a computer power supply?

Take a regular 12V power supply with 2.1x5.5 or 2.5x5.5 plug, plus some splitter cables (you can easily find a 1x8 splitter, maybe even more). Just make sure that your power supply can handle the maximum number of pumps active - with a little programming logic you can probably limit it to one at a time.

Arduinos are more suited to a job like this than Pis. Simpler, easier to program, plenty of I/O ports, much cheaper, and more than powerful enough to handle the work. A single Mega will happily handle all the pumps, add a few ADCs such as the ADS1115 for the extra moisture sensors and you're ready to go.

Instead of using relays, do look into using MOSFETs as switches. They're perfectly suited for a job like this.

3

the first question is how much water you need.
I use pumps that do a quart a minute, others, a gallon, others a few gallons per minute.
as you probably know, it is much easier to have a pump run for a few minutes to deliver the volume than to try to have a 5gpm pump run for a few seconds to deliver a pint.

Also, not sure of your layout. are they over the length of a 100 ft long greenhouse ? or at multiple locations ? or spread all over ?

consider a single pump, filling a hose will have water come out one place.
a solenoid could control which lines of a drip system are open. better if you have a larger section of one plant.

some of the really low cost pumps would be great for smaller plants or small areas.

IMHO, a combination of pumps and solenoids are better. pumps to water soil, solenoids to mist from drip irrigation heads.

If you have a sketch of the crop lay-out, that would be helpful.
also, what power do you have in the area ? Orbit and RainBird have simple valves that are easily controlled with a relay.

4

sennon:
Is there a single power source I can connect multiple 12v dc wires to? Is the only option to mod a computer power supply?

there are pleanty of 12VDC power supplies on e-bay and Amazon.
considder that you would probably on run one pump at any time, and that one pump should not run for more than a few minutes. your supply should only need to be sized to run 2-3 pumps at a time.

If you have a pump picked out, post a link.

5

wvmarle:
Take a regular 12V power supply with 2.1x5.5 or 2.5x5.5 plug, plus some splitter cables (you can easily find a 1x8 splitter, maybe even more). Just make sure that your power supply can handle the maximum number of pumps active - with a little programming logic you can probably limit it to one at a time.

Arduinos are more suited to a job like this than Pis. Simpler, easier to program, plenty of I/O ports, much cheaper, and more than powerful enough to handle the work. A single Mega will happily handle all the pumps, add a few ADCs such as the ADS1115 for the extra moisture sensors and you're ready to go.

Instead of using relays, do look into using MOSFETs as switches. They're perfectly suited for a job like this.

That's unfortunate. I was hoping for power supply tailored for something like this as I am not that confident in my modding or even soldering. I guess there's gotta be a first for something like this.

The need for the raspberry pi is to have it host a web app to adjust the watering levels and moisture ranges as they get a new rotation of plants every month or so. It's actually my friend's dad's nursery and he helps out occasionally since it can be quite the physical labor so I want to be able to write an app to cater to his understanding.

Will a single mega be able to handle all the pumps? How would that work? Is there a specific model for this?

Thanks for the suggestions!

dave-in-nj:
the first question is how much water you need.
I use pumps that do a quart a minute, others, a gallon, others a few gallons per minute.
as you probably know, it is much easier to have a pump run for a few minutes to deliver the volume than to try to have a 5gpm pump run for a few seconds to deliver a pint.

Also, not sure of your layout. are they over the length of a 100 ft long greenhouse ? or at multiple locations ? or spread all over ?

consider a single pump, filling a hose will have water come out one place.
a solenoid could control which lines of a drip system are open. better if you have a larger section of one plant.

some of the really low cost pumps would be great for smaller plants or small areas.

IMHO, a combination of pumps and solenoids are better. pumps to water soil, solenoids to mist from drip irrigation heads.

If you have a sketch of the crop lay-out, that would be helpful.
also, what power do you have in the area ? Orbit and RainBird have simple valves that are easily controlled with a relay.

I guess it's what you would call a typical green house about 50ft by probably 20-30ft in a rectangular fashion. The plants sit on a near waist high table around 8' x 3' though I am not sure how they're sorted. Some of the pots are 4"x 4" while some are 1ft diameter for the trees. The room is basically filled with tables with 3ft distance of each other, nothing high tech just simple room with tables.

Ya it would be nice to be able to use solenoids but the variations are quite large in number for the plants causing some to consume more water than others so ease of adjustments would be preferred. I was thinking of having individual pumps numbered and have the configurations managed by number to make it easier to adjust the settings. I am not sure why they have so many variations but apparently a lot of customers enjoy growing exotic fruits and what not and the more popular ones are generally ordered larger/older.

I currently have an opensprinkler pi watering my 3 dragonfruits that uses solenoids but the issues still require individual power sources.

What do you mean what power do we have in the area? There are a few outlets here and there, about 6 I'd say spread evenly on the sides of the green house if that's what you mean. For my dragonfruits they are currently using RainBird valves/solenoid but they are 24v ac I believe and the adapters are pretty big which I am hoping to avoid.

dave-in-nj:
there are pleanty of 12VDC power supplies on e-bay and Amazon.
considder that you would probably on run one pump at any time, and that one pump should not run for more than a few minutes. your supply should only need to be sized to run 2-3 pumps at a time.

If you have a pump picked out, post a link.

http://www.ebay.com/itm/12V-DC-CPU-Cooling-CAR-Brushless-Water-Oil-Pump-Waterproof-Submersible-H-/172412940231?hash=item28249cafc7:g:kXEAAOSwA3dYLtp~

Is the pump I use to water my bonzai tree which I connect http://www.ebay.com/itm/2017-US-Plug-12V-1A-1000ma-Power-Adapter-for-Tablet-PC-Arduino-5-5mm-x-2-1mm-/152191587539?hash=item236f5354d3:g:-V4AAOSwnQhXoVPC via http://www.ebay.com/itm/5Pair-Male-Female-12V-DC-2-1x5-5mm-Power-Plug-Jack-Adapter-Connector-For-Arduino-/261509775164?epid=1144657240&hash=item3ce3327f3c:g:eksAAOSwhh5TokgF

Since the pumps are cheap enough to order about 100 of I don't think it's reasonable to have 100 outlets but I want to assume that's the worst case scenario as my vision is limited due to my inexperience. My goals are to have everything automated but taking small steps first.

Thanks for the suggestions!

6

Euhm... You really should try to understand what you're doing.
First you reject my suggestion of using standard 12V power supplies which connect through standard 5.5x2.1 mm plugs for being not suitable for you, as you can't connect to such power supplies for whatever reason. Then a bit down the same message you link to exactly those plugs suggesting that is what you want to use?!

7

wvmarle:
Euhm... You really should try to understand what you're doing.
First you reject my suggestion of using standard 12V power supplies which connect through standard 5.5x2.1 mm plugs for being not suitable for you, as you can't connect to such power supplies for whatever reason. Then a bit down the same message you link to exactly those plugs suggesting that is what you want to use?!

No, you misunderstand. I never rejected your idea, I even mentioned it was going to be a first modding a power supply inferring it was probably something I may end up doing

In the later responses I was reiterating what my intentions and concerns on the project to dave-in-nj in case he had alternative suggestions. I want to know all my options before committing to a potentially large project.

8

There is no modding power supplies involved. Just plugging things together. I'm quite sure you're doing the same every day with line voltages - this is no different, other than that the connectors look a bit different.

9

wvmarle:
There is no modding power supplies involved. Just plugging things together. I'm quite sure you're doing the same every day with line voltages - this is no different, other than that the connectors look a bit different.

It seems I may have understood but your original answer was exactly what I was looking for. Since I mentioned using a computer power supply I also assumed you were speaking of the same concept which caused me to misunderstand. Thanks for the suggestion, now I can proceed with setting up a test project.

10

Computer power suppliers may work as well - but likely overkill. You probably need only 2-5 A, depending on how much power your strongest pump draws. Just make sure you don't switch them on all at once :slight_smile:

Good luck with your project!

But do remember, start small. One pump. Then two (and figure out how to operate them independently but never at the same time - e.g. by setting a global boolean pumpRunning when any one pump is active). Then the rest (once you figure out how to do two, the rest is just more of the same).

11

I highly suggest you sketch out the garden/plots/etc

Since you say you have outlets, that means 120 volts power ? ( USA ? vs 220 in other parts of the world ? )

I would offer that you could make a box, with 4 or 8 inputs and 4 or 8 outputs and then have one Arduino in that.

have one hose connection that splits water into 4 or 8 solenoids for drippers.
I really like dippers as you can control the volume with adding heads or using misters.

Pumps require a resovour to pump from.

I would offer that you can get a 12V power supply that is like a mini-PC power supply. very simple.

one idea is to have 10 separate boxes, with 8 relays/solenoids in each.
control would be local. the Arduino would turn things on and off, but
you could change that from your PI, or data log as well.

depends more on your strengths of programming than on making the hardware work.

What part of the world do you call home ?

12

There are well-established commercial suppliers for this sort of kit. I have friends with several acres of glass
who grow for a living.

google 'nursery irrigation'.

If this is a commercial nursery the crops are valuable, and your experiments if they fail might be expensive.

Allan