Automatic Plant Grower

I made a system which lights a plant and controls a water pump to water a plant based on the moisture of the soil.

1 5v Pump

Airline Tubing

1 Capacitive Soil Moisture Sensor

1 5v Relay

1 LED Strip

1 Arduino Uno

Jumper Wires

1 External 5v Power Supply

1 Plant

1 Container for Water

1 Box

I wanted to have some kind of lighting for the plant. I found a long spool of LED lights and decided to use them. I cut pieces of twelve lights and soldered them in sequence. This would allow me to bend them to make them into a rectangle.

In order to get the signal of the moisture sensor, plug the corresponding wires to ground, any analog pin for the signal, and 3.3v for power. Then, wire the led strip with power, ground, and any digital signal. Next, wire the relay by using power, ground, and another digital signal. Then power the pump using an external power source. I cut up an old usb cable and connected the power of that to the power of the pump. Then connect the grounds of the power cable and the pump to the relay. A relay works essentially as a switch. It has a common wire, an nc (normally closed) wire, and a no (normally open) wire. I choose to connect the ground of the pump to the common and the ground of the power source to the normally open. When the relay turned on based on the signal coming in, the normally open and common would complete the circuit and run the pump. I also set a digital pin as an output to create another power pin on the board.

Follow the code to set up the system. The pins are defined at the top and then there is some logic to control the lights for a set amount of time. You can play around with the signal of the soil moisture sensor to determine when the soil is wet and dry and then set the level at which you want the pump to turn on.

I had not thoroughly planned how I was going to house everything and so my design is not the cleanest looking one. I first made a piece to hold the plant and have a light over it. I had not thought about where the water and arduino would go. I then made a box for the water and arduino but did not plan where to put it. Ideally, the arduino and water container can go flush behind or even under the light and plant piece. I used a laser cutter to cut the pieces for the lights and then a 3d printer for the water container. Feel free to get creative and make these parts from anything. You just want to manage the wires and keep the arduino dry.

Once all my parts were printed, I powered everything and confirmed everything was working by removing the soil moisture sensor and seeing whether the plant turned on.