o3893347:
Does the same apply if I use pumps instead of solenoids for irrigation?
Yes, as long as the pump draws less than 150mA. Same for the solenoid. If you need more than 150mA, there is the TPIC6A595 which can handle 250mA. More than that, and you will need to use individual MOSFETS for each device. The MOSFETS can be controlled by the tpic chip, or an ordinary 74HC595 shift register, or an Arduino pin.
dave-in-nj:
I understand of would often agree. however,
OP has 3 separate but nearly identical growing areas
he is Dirt Farming.
As the new farmer evolves He will want to add features, monitor other things. Control other things, etc.
Any alteration or modification offers a potential to loose the whole farm.if he wants to add a 4th area, then he has a choice to risk all crops by taking his one out of service and making the sketch for the 4th perfect the first time.
if he wants to alter some water levels or patterns, he has to be perfect.it he wants to expand to a second area, he will need to duplicate the whole control.
Not with code that can add or remove sections.
This is like making a project with 3 buttons and saying you'd need another board to add a button. Not necessarily, not at all in this case.
Growing in dirt in a display case inside of your house does rule out much system growth. He's not even going for a high CO2 content atmosphere inside the growing area. One controller can manage a heck of a lot more garden than that.
But if the code for the controller is poorly made, self-blocking jerky stuttery do 1 thing at a time while pretending to juggle 3 or 4 simple tasks then yeah sure, you need one controller for just about every other little thing needing done.
GoForSmoke:
...But if the code for the controller is poorly made, self-blocking jerky stuttery do 1 thing at a time while pretending to juggle 3 or 4 simple tasks then yeah sure, you need one controller for just about every other little thing needing done.
I don't mean to knock the new guy, but he is asking what boards to use and seems to not know about shift registers.
that puts the likelihood of jittery code into the forefront.
My point is that buying one nano, one TPIC6595, one CB4021BE for intputs and one 74HC4051 for analog expansion....
for a beginner, using multiple NANO's will teach them how to address inputs and outputs directly and with more understanding.
as one grows the needs their understanding and knowledge grow and these things come in time.
3 NANO's cost about the same as a MEGA.
one NANO and multiple chips offers more places for problems, delays and confusion.
IMHO, it comes down to what stage the OP is able to work with.
I am new to arduino and I haven't used shift registers before, but I am a programmer, so I'm not worried about code that doesn't work. The challenge for me is understand the electronics.
Any recommedations for pumps and light fittings?
o3893347:
Any recommedations for pumps and light fittings?
tiny pump, comes in 3volt, 5 volt, 6 volt, 12 volt...
PUMP
make sure of the voltage. these are cheap. get an extra one.
if you are not familiar with this stuff, get a Tee fitting, place at the water level outside of the upper tank
add a hose to it and let it be open over the water.
when pumping, the water fill flow.
the tee will allow air and prevent a siphon.
I think it was from a bucket to a gallon milk jug, no vertical lift. took over a minute to fill the milk jug.
not sure how large your planters are, but if you have a 5 gallon container, these will be a good choice.
for hose, I think the OD of the tiny pump is 6mm. HOSE
so the 6mm x 8mm is the large size.
5mm ID might be tight.
tee fittings for drip hose TEE FITTING
DRIP HOSE will be a tight fit to the fittings. I boil water, hold the hose in it,then put on the fitting.
for the softer hose I use bread ties, the little wire in a paper/plastic section.
oh, and the SOIL MOISTURE SENSOR
one note about AliExpress, if you look around, you can often find things that are free shipping.
If you don't switch them very frequently, relays are a good cheap way to switch 120VAC/240VAC/24VDC on and off. A relay that Arduino can control, relay with 10A capacity costs about $2. For more amps, more cost. 10A of 240VAC is 2400W power... how much pump do you need?
For programming there are differences between the chip and the PC, biggest is resources but there is also the 8-bit word and lack of FPU and 64-bit double variables. There is also no OS on Arduino -- you make your own bugs now, Microsoft won't help you no more with those!
Really the "mission" these chips were made is automation and these chips are more suited to that than your PC. Together... they could truely be the hunter and his dog(s), you may find later.
There is a lesson shown here and on the web called "do many things at once" that is key to multi-tasking without an OS. It is cooperative tasking and if your code does not block it can do many things with response times of less than a millisecond. If you have no task that hogs cycles, response can be less than a tenth of a millisecond using these techniques.
I am guessing that you already know about state machines, something else to pick up if not just for the usefulness.
You should want to skim through the links on this page: https://www.arduino.cc/en/Tutorial/Foundations
just to find differences and features you will encounter with Arduino, mostly hardware and software for it.
Things to avoid like the plague: dynamic allocation and all C++ objects that use it, including String objects. If you never learned C char array strings, take the time to cover that, it will be less than you waste by skipping it. You do not need to learn string.h commands to use strings, they're char arrays you can process like any array.
PS -- for shading plants from room light, perhaps vertical blinds?
Great, thanks for the advice everyone.
I'm especially interested in any suggestions on how to roll a cloth screen down over a compartment on a timer
Search "blackout roller shade" The motorized ones are expensive but the self retracting style can be made to work with a string and a pulley mounted on a stepper motor 
gregory007:
Maybe he will use marijuana for producing cbd, who knows..
Maybe he or she was in Canada back then in 2018.
waldenverney:
TBH, I think that growing weed on your own is too damn hard. And, as a CBD user, I can't imagine the cheap method of making CBD out of it. Maybe you're just wasting your time, OP?
No point trying to use logic and common sense against someone who considers that voluntarily ingesting brain destroying poisons is somehow a clever idea.
Not like alcohol or tobacco then. 
Paul__B:
Not like alcohol or tobacco then.
Very much like them, although the body is designed to absorb small quantities of alcohol of course. It just amazes me that so many people want to BE affected by these substances. I know life's a bitch but come on, why deliberately damage yourself and pay good money for the privilige?
That argument strongly suggests you do drink alcohol then. I rarely do myself.
You are of course correct.
It is interesting to note in respect of psychoactive substances, that their effect in most cases and particularly where derived from plants is based on imitation of an endogenous neurotransmitter, that is one that already exists in the body. The extent to which they are "brain destroying poisons" - that is, actually toxic - is questionable and can be compared to alcohol which is to say it depends on the amount used. 
"That argument strongly suggests you do drink alcohol then. I rarely do myself."
It's quite a rare thing. I quite like an occasional drop of port and I get a bottle at Christmas every year. It's quite common for there to be half a bottle left for the following Christmas!
I was 17 and in my first job. My boss' son had a birthday party which I attended. Unbeknown to me, he was spiking my drink and I found out that night what "paralytic" actually meant. That was the first and the last time.
waldenverney:
TBH, I think that growing weed on your own is too damn hard. And, as a CBD user, I can't imagine the cheap method of making CBD out of it. Maybe you're just wasting your time, OP?
Speaking of wasting your time, this thread originated in 2018 and this is the second time it's been zombied.
Please check thread dates and don't resurrect old threads. If you care, start your own.
Looks like Hutkikz just lurched out of hibernation. 
Never mind, we had a bit of fun - I mean - intelligent discussion.
Noted AJLElectronics' Avatar. 
We grow our "legal" limit of 4 plants.
The good stuff mostly goes to friends but the rest gets broken down for CBD which is actually quite easy.
Since starting to use CBD based products some of us have noticed a marked turndown in joint pain and a couple of other ailments.
And seeing as we have ideal growing conditions it often means a bumper crop, a family gathering and enough of everything to share and last a considerable time at much cheaper than can be had from official sources.
Doesn't work for everyone but dont knock it till you have tried it.
As for "toxic effects" they have been shown to reduce after the age of 24 I think it is and at 60+ I dont think it will too much to what is left of my mind.
and at 60+ I dont think it will too much to what is left of my mind.
and at 60+ I dont think it will too much to what is left of my mind.
and at 60+ I dont think it will too much to what is left of my mind.
Oh and currently designing an irrigation system for ours to run from a rain barrel with Arduinos of course.
Rant/ Best get the software done quick before your brain is frazzled /rant.
hammy:
Rant/ Best get the software done quick before you brain us frazzled /rant.
Ya sed whut ?
wait i is ungry wot we ave in cubord....munch munch munch.
now wut woz ye sayin ?