This project is extremely useful during summer. It is when many  plants die a slow, withering death from neglect due to lack of weeding and watering. The automated Irrigation system’s mechanism is this “Did it rain yesterday? If not, water the plants”. It only focuses on mainly being able to water the plants and nothing else.

It sounds pretty simple but you need to have a lot of things to start. With all these list, it really does require a huge amount of hard work. It needs to have a lot of coding skills. This project could last a little longer than you expected.

Here is the list:


  • Raspberry Pi 3. Used because it has built-in WiFi, but you could do this with an earlier model.
  • 5.25V, 2.4A micro-USB power supply. Recommended for the RPi3, older models do not require as much current.
  • Micro SD card with adapter. 8GB recommended, newer versions of Raspbian Jessie don’t seem to fit on 4GB cards (unless you plan to install the lite version and only run headless).
  • Relay. I debated using a solid-state AC relay, but this mechanical relay is rated for 100,000 operations at max electrical load – we are well below that limit if you’re only watering a couple times a day.
  • N-channel MOSFET. Required because the RPi’s GPIO pins cannot drive the relay coil directly.
  • 2-pin screw terminals (2)
  • Protoboard or breadboard of your choice
  • Green LED (3), used as status indicators
  • Rectifier diode
  • Male/female jumper wires, for connecting to Raspberry Pi GPIO pins
  • 22 AWG solid hookup wire, for making connections on protoboard
  • Female header pins
  • 220 ohm resistor (3)
  • 20 AWG stranded hookup wire, for connecting solenoid valve (note that you may need thicker wire if you need to run the wires really far, consult a chart like this to determine what you need)
  • 24 VAC 1500mA AC to AC wall adapter. Important: make sure the rating of this adapter matches the requirements of the solenoid valve you purchase! (some valves are DC)
  • Optional: monitor for Raspberry Pi. I found a monitor useful for setup and debugging, but once it’s working you should be able to run the RPi headless (without a monitor). See instructions for connecting to the RPi remotely viaVNC or SSH if you do not have a monitor.
  • Project box (small cardboard box or plastic container)

Plumbing (note: NPT = National Pipe Thread, MHT/FHT = Male/Female Hose Thread)


  • Hacksaw or miter saw to cut PVC pipe
  • Shovel, hoe, or trenching spade etc. to dig trenches for pipe
  • Wire strippers
  • Soldering iron

If you can manage to have these materials you can check this schematic to see how it actually works!

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If you want to proceed with the project, you can click here for more details!