Would this pump be compatible with Arduino?

I'm doing my first build. A self-watering project for my chilli seedlings.

Would this pump be a good choice. How would I control it with my Arduino?

That is a 4W pump that runs on the main voltage.
You need a relay or small SSR (Solid State Relay) to switch it on and off.
A relay module is perhaps the most simple solution.

There are also 12V pumps, if you are not sure about mains safety.

I can’t see the electrical specs there, or any details about pressure and flow rates. If it’s a DC brushed motor you ought to be able to drive it via a motor driver circuit that has the necessary voltage and current rating.

In case it’s any help, I made an automatic water sensing / watering system a couple of years ago using a tiny DC brushless motor water pump that cost about five quid, and a Pololu Baby Orangutan board with an integral dual h-bridge that is good for about 1A per channel. The whole thing is powered by a 1A wall wart. It’s usually not recommended to power the Arduino from the same source as a motor because of noise issues, but in this case there hasn’t been any problem.

Thank you both very much. PeterH, any chance you have a link to sketches, schematics or anything? I’m looking to crib all the help I can until I get my whereabouts.

Oh, and also, are 12v pumps being suggested because they are safer? I'm starting to think I may be in over my head if I'm missing out on fundamental safety points.

Oscar_Zeta_Acosta:
Oh, and also, are 12v pumps being suggested because they are safer?

Absolutely yes. You need to be extremely cautious about anything involving mains voltages, and doubly so when it involves water as well. Small DC pumps are easily and cheaply available, much easier to use and have no significant safety issues.

OK, got it thanks. I've been doing some more reading; do | want a 12v DC brushless or brushed motor in the pump?

This one is brushless: http://www.amazon.co.uk/Micro-Cooling-Brushless-Water-Waterproof/dp/B00BXVQ496/ref=sr_1_2?ie=UTF8&qid=1395502448&sr=8-2&keywords=12v+water+pump

Brushless is better when it's immersed, and that looks like a reasonable choice. It only draws 350mA so it would be easy to drive.

What mA draw can the Mega 2560 safely handle? I just read 300 mA somewhere but figure that can't be correct?

EDIT: or do I somehow power the pump with a separate 12v supply? If so, how does the arduino talk to the pump to tell it to pump water when the soil sensor conditions are met?

EDIT 2: perhaps I should use this one which has a nice female connector for me to plug a 12v adapter (wall wart?) into: http://www.amazon.co.uk/DC12V-Submersible-Water-Aquarium-Fountain/dp/B008OPKSC8/ref=pd_sim_sbs_petsupplies_1?ie=UTF8&refRID=0F994Q79HFSSSH1TFND7 If I'm correct, 3W at 12v DC is 250 mA? And then do I somehow use a relay or MOSFET to control the pump on/off via the Arduino? But do I have to dimsantle the pump to get it to connect to the relay??

Apologies for the somewhat basic questions :blush:

Basic questions, but good questions :slight_smile:

You need power for the pump. The Arduino can not supply that.
With a power supply of 12V, you can use that for the pump, and for the Arduino board.

If the voltage regulator on the Arduino board gets hot, you need a lower voltage for the Arduino board. For example when you have connected (too many) leds to the arduino board.

Those pumps are both 12V pumps. You can use either of them.
A “Brushless” motor is different and is better. And you can brag to others: “Yea, I used a brushless motor”.

I doubt if the pump of 10 pounds is really brushless, I don’t know if they can be made that cheap.
Sometimes ‘coreless’ motors are called ‘brushless’, but that is a scam.

To switch the motor on and off, you need a transistor or darlington transistor or a ‘logic level’ mosfet or a relay.
A relay makes sound “click” and “cloinck”, so a mosfet is more fun.
You connect the wires of the pump to 12V and the mosfet, and with a protection resistor to the gate, and fly-back diode over the pump.

Caltoa:
I doubt if the pump of 10 pounds is really brushless, I don't know if they can be made that cheap.
Sometimes 'coreless' motors are called 'brushless', but that is a scam.

My pump I use is described as having a brushless motor. To be honest I don't know or care whether it's truly brushless - all I care about is that I don't need any external controller; I just apply power and it runs, just like an ordinary brushed DC motor.

I bought a ‘brushless’ motor, and opened it… it was coreless. But I got my money back.

Thanks gents. I've been reading and reading (should really get some sleep now as it's 3.40 am :astonished: ) and I think a relay would be easier than a mosfet. I'm not worried about noise.

So, if my reading is serving me, I think I need to build one of these? Arduino Controlled Relay Box : 6 Steps (with Pictures) - Instructables

But I don't need a GFCI (think we call it an RCD in the UK) becuase I'm powering a 12v DC fan?

So, 1 x relay, 1 x breadboard, 1 x transistor, 1 x diode, 1 x resistor (type 1), 2 x reistor (type 2), 1 x LED. Do I need all of those (I don't want to compromise on safety, but no point in me ordering things I don't need). Would those exact ratings/types be OK for me?

I was thinking buying a motor shield (is that basically like the relay board above?) might be easier but those seem to be intended for driving more than one motor and therefore overkill?

Would appreciate your views before I start ordering. This project has cost quite a bit already (Arduino Mega + VH400) so will need to keep this one quiet from my wife :cold_sweat:

Edit: maybe this works. Does it have all the components already in it? http://www.amazon.co.uk/gp/aw/d/B009P04ZKC/ref=pd_aw_sbs_2?pi=SL500_SS115

The schematic on that sainsmart relay board has a "D?" in it. Does that mean it has a fly-back diode or does it mean the manufacturer isn't sure if it remembered to put one in?? :roll_eyes:

Oscar_Zeta_Acosta:
The schematic on that sainsmart relay board has a "D?" in it. Does that mean it has a fly-back diode or does it mean the manufacturer isn't sure if it remembered to put one in?? :roll_eyes:

2-Channel 5V Relay Module | SainSmart – SainSmart.com

that board has optoisolators so you can think in terms of lighting an LED from the Arduino.

not sure how much more you are trying to do, but a mini could handle simple projects like a garden or simple fish tanks.

get that relay, you only need one relay, not a dual.
connect it in electrical box like instructables shows
by the way, that is a deep box, not a normal one. I have used double wide, shallow boxes as I think they are easier to mount.
and they make gasketed covers for them.

you need to feed the relay control side, power from a power supply, not from the pins of the arduino. same power supply as the arduino would be fine.

then connect the signal side of the relay and it should work great.

the only extra part might be a 220 ohm resistor between the arduino pin and the relay.

just remember ONLY high voltage on the side of the board with the screw terminals.
and ONLY low power on the side with the pins and opto-coupler.

Thanks Dave. So, does the optoisolator work instead of a flyback diode i.e. the optioisolator acts to stop reverse current when using a dc motor?

Why would I not be able to feed the relay board with power from the Arduino pin out? What kind of power supply would have two connections (1 for arduino and one for relay board) please?

The Adafruit Motor Shield v2 says it has a built in flyback diodes so that actually seems to be a good choice for an idiot beginner like me? Overview | Adafruit Motor Shield V2 | Adafruit Learning System

Seems I can connect 2 x 12v dc pumps to it too so I can water my chillies from two different sides at the same time!

Oscar_Zeta_Acosta:
Why would I not be able to feed the relay board with power from the Arduino pin out?

I wouldn't recommend that - you don't want the power to the relay to go through the Arduino.

OK, I'm going to get the adafruit board as it seems to give me the simplest route to where I need to be.

On a related safety note, the 12v dc submersible pump I am ordering has two wires (red and black). My rudimentary knowledge of electricity tells me electricity + water = take care! So, I'm wondering why not three wires, one being a ground wire?

EDIT: and is what this chap is doing dangerous? - YouTube

12V is perfectly safe, it's only when you get to 50V and upwards that you need to start worrying about shock hazards.