I am looking as a first project after some simple project kits, to make a watering system for my indoor plants. I have seen a few projects on instructables, so I went to look for components. I am not sure how to power the pump from the Arduino.

My idea is the following:

A bucket of water with a water pump inside. An irrigation system linked to the pump, which then goes to all the plants. The pump linked to arduino which turns it on and off based on a timer.

The components that I will be using are an Arduino uno and:

Also I guess I will need some tube to connect the pump to the watering kit.

I am not sure how to connect and power the pump (12V) with the arduino. The arduino it self will be powered by a USB on a wall socket.

  • Use an external 12V power supply and switch it with a suitable transistor or MOSFET.
    – Majenko
    Commented Jul 3, 2015 at 22:05

1 Answer 1


I have some details about running motors etc. from Arduino pins at Driving motors, lights, etc. from an Arduino output pin.

Quite possibly what would work for you is a MOSFET - as Majenko suggested - connected up like this:

Low-side MOSFET driver

In this case you connect the positive side of your 12V supply for your pump to the pump, and the MOSFET sinks current to ground, when you require the pump on.

Don't forget the diode D1 which prevents damage from the inductive load of the pump generating high-voltage spikes.

  • Yes, though getting a MOSTFET setup right can take some care as they are a bit delicate electrically, so someone doing this for the first time may find it easier to use one of those extremely cheap relay boards. If the pump is going to either be off or on for at least a few seconds at a time this should work just as well - where a MOSFET really recommends itself is when the pump speed is to be controlled by rapidly switching it on and off hundreds to thousands of times a second. Commented Jul 4, 2015 at 14:21
  • I was about to ask this, I was aware of these Relays, but now I guess I learn something new. I do only care only for On/Off
    – Giannis
    Commented Jul 4, 2015 at 23:13
  • You can get digital relays which I'm not sure if that is what @ChrisStratton meant. Effectively they would have a MOSFET in them. If you get a mechanical relay you have the issue of adequately driving the relay coil, and installing a flyback diode to protect yourself from that coil.
    – Nick Gammon
    Commented Jul 4, 2015 at 23:17
  • 1
    No, electromechanical. Small electromechanical relays require very little to drive - and are commonly sold on boards with an isolated driver and flyback diode. These are conceptually a lot simpler to deal with, and don't have the same ESD fragility, making them a lot more beginner-friendly. Commented Jul 5, 2015 at 0:27

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