Smart Irrigation System

Water conservation has become an increasingly frequent topic recently. The alternation of long dry periods with intense rainfall causes many complications. If you have a garden near your house where you grow your own vegetables, you may have already thought about how to achieve water savings. A smart watering system that delivers water based on soil moisture could be a solution for you and your smart/autonomous garden.

Commercial smart watering solutions

There are many smart watering systems that work with various apps. Some of these irrigation controllers keep track of the amount of water that has been used let you check the whole process on your smartphone.

However, if you prefer your own DIY solution, you may integrate a cheap smart watering system in your garden easily any complex. This solution won’t let you check the complete watering process, however, it is so simple that even your kids can build it, e.g. as a part of a school project.

How to build a smart watering system for your garden

Therefore, if you have a garden or flowerpots that need to be watered regularly, you can easily build this project yourself and you won’t have to pay for its installation. All you need is a small water tank, a low-performance water pump, a power source, a soil moisture sensor, and a controller with a relay.

Things you need

Water tank – a water barrel with a volume big enough to the bed or pot you want to water is sufficient.

12 VDC submersible water pump – you can use a water pump for fish tanks. Like this one:

AliExpress.com Product – 3W 5.5V-12V DC Submersible Water Pump IP68 Waterproof Solar Motor 200L/H 0.4-1.5M For Aquarium Fountain Fish Tank Watering Tools

XH-M214 Humidity Controller (Soil Sensor Module Board) – this is a cheap set of controller and moisture sensor with a relay which powers the pump:

AliExpress.com Product – XH-M214 12V Soil Humidity Sensor Controller Irrigation System Automatic Watering Module Digital Display Humidity Controller Red

Power adapter (100 VAC or 230 VAC to 12 VDC) – e.g. an adapter that is used for LED lighting should be OK as most of these adapters deliver enough power for the water pump. If you need an autonomous system, you can replace the adapter with a 12 V adapter.

AliExpress.com Product – 100-240V AC to DC Power Adapter Supply Charger 12V 9V 5V 1A 2A 3A 0.5A 2.5mm x 2.5mm EU Plug Converter for Led Light Strip Lamp

Plastic tubes that fit the pump – choose the diameter that suits the pump, and the length to deliver the water from the tank to your plants.

How to install the watering system

You need to cut the original connectors from both the pump and the power source, so you can connect them to the terminal on the controller as follows:

Watering system connection / wiring

After the module is powered, you need to set the F0 value (the moisture value when the pump is activated) and the F1 value (the upper level of moisture to turn the pump off). Simply choose the value you want to change by the SET button and check the display.

You can test the device with a flower pot and a glass of water just to see how it works and to set the right values.

Things to consider

Be careful about the elevation – the water pump used in this project is only suitable for a height difference of 1-1.5 metres. It might not deliver water to elevated flower pots.

Fill the tank regularly to keep the pump from running empty. The pump is cooled by running water and could be damaged or catch fire if it runs dry.

Before you leave the system unattended, check it regularly – whether it is not overwatering; how long it takes to drain the water from the tank.