Self-Watering Plant Pot

This is our self-watering plant pot. Our goal is to make a pot that reduces water waste and is easy to use for new plant owners. The pot is programmed so that water can be added when the soil moisture is low, and excess water can be reused.

The pot has two layers. The top layer has a mini pot containing the plant in the middle, and the space around the pot is for the electrical components (breadboard and wiring). The soil moisture sensor makes it so that the right amount of water can be added to the plant when needed. The bottom layer contains the water, a submersible water pump, and a water level sensor that allows users to know when to refill. There is a tube on the outside that allows the water pump to push water up to the plant, and a tube inside the minipot (containing the plant) that allows users to add more water to the pot. The minipot has holes in the bottom, which allows the plant's excess water to drip back into the reservoir so it can be reused.

1. Arduino Nano
2. Mini submersible pump with plastic tubing
3. Transistor (1x 2N2222)
4. Resistors (1 x 1k and 1 x 4.7k)
5. Solid core 22 AWG wire
6. 3mm LED
7. Water level sensor
8. Soil moisture sensor
9. Half Perma-proto board
10. PLA Filament
11. Epoxy resin and hardener

The top pot is an open-ended cylinder with a smaller cylinder inside it. This smaller pot is where the plant will go, while the area around it is for the electrical components. The attached rounded rectangle is the water pump tube, which will house the plastic tubing of the water pump that carries the water up from the water reservoir level.

This is the sketch for the top part of the pot. Create 4 concentric circles, of diameters 4, 4.5, 7, and 7.5 inches. The inner circles will contain the plant. It is important that there is a large gap between the inner and outer pot for the electrical system.

This is the sketch of the water pump tube, which is attached to the outer wall of the pot. Create two concentric circles, of diameters 0.73 and 0.34 in., respectively. Connect the circles to the outer wall of the pot with 0.5 in. legs. Trim the excess parts until it looks like the sketch above.

Extrude:

Extrude the inner ring up by 6.5 inches.

Extrude the 4.5 in. circle down by 0.5 in.

Extrude the outer ring and the tube out by 6.5 in.

Extrude the outermost circle and part of the tube down 0.5 in.

Select the inside of the tube sketch and extrude it as a cut until the tube is hollow.

This is the sketch for the bottom part of the pot. It is a wide, empty cylinder that will contain the water, the water level sensor, and the submersible water pump. Create concentric circles with diameters of 6.20 and 7.50 in. The wall needs to be at least 0.65 in. thick in order to allow this part of the pot to connect to the top part once printed. Then create the tube, which should be identical to the sketch in Step 1. Add a 0.675 by 0.34 rectangle underneath the sketch for the tube (circled in red). When extruded, this rectangle will become the cut that allows the plastic part of the water pump to enter the tube.

Extrude the walls and tube of the bottom pot up down 2.90 in.

Then, highlight copy- the outermost walls of the sketch for the bottom pot (highlighted in blue).

Create a sketch on the bottom of the part that was just extruded (just the walls). Paste the part that was copied onto this sketch (it should line up with the sketch it was copied from).

Extrude this sketch down by 0.1 in. so that the pot has a solid base.

This is the sketch for the layer of holes that go underneath the inner pot (which contains the plant). These holes will allow excess water to drain out of the plant, so that the pot can reuse water. Create a sketch on the base. of the top part of the pot. Create a 4 in. circle. Then create a 0.20 in. circle inside it, and then copy-paste the small circle 3 times, making a line from the edge to the center. Then, make a circular pattern to repeat the line of small circles around the large one.

Extrude the circles as a 0.50 in. cut.

There needs to be a cut in the wall of the pot (in front of the water pump tube), so that the plastic tubing can enter the tube that goes up the pot. Go back to the sketch for the bottom pot. Click on the 0.675 by 0.34 rectangle (highlighted in blue) and extrude it as a cut 2.10 in. down.

This is for the plastic tubing that is part of the water pump. The plastic tubing has to go through the outside tube in order to transport the water up to the plant.

The tube that allows the user to refill water for the pot goes through the middle of the pot. It is connected to the wall of the inner pot. On top of the inside pot (where the plant is) create a new sketch (on surface with blue star).

Create another tube sketch on the inner wall of the inner pot. Make two lines extending from the wall that are 0.75 in. long and 1 in. apart. Then, attach a tangent arc with a 0.5 in. radius.

Extrude the sketch as a cut down 0.5 in. (so it can cut through the middle layer of the pot). Then, extrude the sketch as a join up by 6.50 in.

After extruding, the pot should look like this.

Side cross-section analysis:

The ledge on top of the wall of the inner pot will allow the wires connecting to the soil moisture sensor to neatly go over the wall.

Create a sketch on top of the inner pot wall, opposite the water refill tube. Make a 0.75 by 1 in. rectangle that goes over the wall.

Extrude the highlighted section as a cut 0.25 in. down.

The ledge will look like this:

You need to create a hole between the layers of the pot that allows the wires from the water level sensor and water pump to go up to the electrical level.

Create a sketch on the middle layer, around the inner pot. Make a 0.75 in. circle.

Extrude the circle 0.5 in. down to create a hole. This will allow the wires from the water level sensor and water pump to go up to the electrical level.

Create a 0.25 in. diameter hole that goes through the side of the pot, around 6.3 in. from the base. The hole should go through the outermost wall.

Next, CAD the flower-shaped tube that will point the plastic tubing of the water pump at the plant.

Start with the stem. Create a sketch on the top plane with lines and an arc, similar to both tube sketches, using the dimensions above. Then, on the right plane, create a sketch of a spline.

Loft the first sketch using the arc as a path.

On the front plane, on top of the end of the stem, create a sketch of the flower.

Extrude the petal parts of the flower (excluding inner circles) by 0.2 in.

Extrude the inner circles by 0.6 in.

Extrude the inner rectangle back 0.30 in. as a cut.

We printed our pot on a PRUSA 3d printer. Before slicing the design on PRUSA, cut the design in order to print it in two parts. Cut the design at 2.90 in. from the bottom, and add “Plug” connectors. Place two connectors on either side of the tube, and then place 3 more plug connectors around the pot rim. Copy the other part of the pot (which should have the corresponding connectors) and after saving the first part on a USB, paste the deleted part and save it on another USB. Print the top and bottom pot simultaneously, on separate printers.

Top pot, printed:

Gather all the electrical components (solder, F-M pin wires, water level sensor, soil moisture sensor and module, submersible water pump, Arduino Nano, breadboard). Here, we used a solderless breadboard, but PCBs and other soldering boards are useful as well.

First, solder the Arduino Nano board to the pins. Attach the pins to the board. Then, heat the lead-free solder with a soldering iron until it melts, and place a tiny dot of the molten metal onto the pin, so that it sticks to the board. Repeat for each pin, until the entire Arduino board is stuck to the pins.

Attach the Arduino to the solderless breadboard. Use F-M and F-F pin wires to connect the water level sensor, soil moisture sensor, and submersible water pump to the breadboard. You will also need some pieces of wire to connect parts of the breadboard. Cut and strip short pieces.

Follow this circuit diagram to complete the breadboard.

When attaching the water level sensor and pump, make sure the wires go from the sensor/pump through the hole in the top pot, to the area surrounding the inner pot, which is where the breadboard will go. When attaching the LED, put the LED legs in the hole from the outside, and then attach the wires to the legs, so that the LED stays outside the pot.

This self-watering plant system continuously monitors soil moisture and water levels. When powered on, the LED blinks to confirm operation. It then reads the water level sensor and soil moisture sensor, displaying the values on a computer. If the soil is too dry (moisture level below 600), the pump turns on briefly to water the plant, then pauses to let the moisture spread. This cycle repeats, ensuring the plant stays hydrated automatically.

We printed out pot in PLA and PLA isn’t water proof so we coated the pot pieces with resin. To make the resin mixture, mix equal amounts of epoxy resin and hardener in a small plastic cup. Then, using a popsicle stick or toothpick to spread the resin mixture across the inside (base and sides) of the water reservoir pot, the inside of the inner plant pot (innermost pot with holes), and the inside of the water refill tube. Leave to dry for at least 24 hours.

1. Glue the water level sensor to the inner wall of the water reservoir, upright.

To Use:

Place your plant of choice (that you adapted the code to) in the center of the top pot, with soil. Fill the bottom reservoir with water.