Introduction: Solar Watering System Without Battery

In this instructable I want to explain how i built a system that give water to the plants whenever is needed even during holidays. The plants need water depending on how much moisture is in the air and sometimes is hard keep in mind that you should water them.Even if this project is in a small scale you can modify it to suit your needs. You can expand this system to water your garden or your solarium using pipe "multiplexers" and bigger pump and reservoir.

I have used solar energy because during spring and summer most of the time is sunny and this is a good resource. Even if is cloudy the system could work, at least it should have more or less than 5 minutes of bright sun in order for the pump to give water. Let`s begin!


What you need:

-Arduino nano

-Solar panel at least 6v 2W

-Step-down reguator (or 5v regulator)

-male and female pin headers (40 female pins and 10 male pins)

-Water pump appropriate for the solar panel

-Moisture sensor(resistive or capacitive); capacitive sensor is more resistant and accurate

-perfboard(blank pcb)with dots


-terminal blocks with two screws X2

-10 Kohm resistor(for diy level sensor)

-1 Kohm resistor(for the led long leg, depending on brightness)


-Mosfet, transistor or relay(relay is easier to work with and can switch AC loads)

-Soldering iron

-Soldering wire


-Solder wick

-Isolated wires(small for pcb and long for the panel and motor)

-Heat shrink tube (depending on wire diameter)

-Old batteries or pencils for the graphite bar( i learned from a forum that graphite is resistant to electrolysis)

-flexible water pipe(appropriate for the pump)(i used 7mm diameter)

You can buy from where you want, almost all the things can be different depending on the scale of the system. For the PCB you need practice and a lot of patience :)

Step 1: Circuit

If you want you can connect all the components on a breadboard if you don`t want to solder.I am first time soldering so i definitely need more practice.Even if you think that soldering is hard, it is not( the secret is the temperature because the solder tends to stay on the tip if it is not heat enough)

This is the link for the Tinkercad design: System circuit (arduino and the motor are powered from the regulator)

Step 2: Making the PCB

First place the regulator, arduino and screw terminals on the board in a way you can connect the regulator to arduino and a screw terminal .

Step 3: Soldering the Terminals

Place the terminals on the small edge of the board and flip the board over. Start by placing the iron to a pin and apply the solder on that heated pin (try to heat the leg for around 5 seconds or less).

Step 4: Cutting Pins and Soldering Them

Cut the pins by removing the little fork of the pin you want to cut and then break them with pliers and sand the edges.

Place the arduino with the headers attached( 2 rows of 15) on the board and then solder ends of the rows, also you will need to cut a pair of four and a pair of two.

Continue by soldering all the remaining legs.

Step 5: Soldering the Regulator in Place

Start by soldering male pins on the regulator in order to connect to the perfboard and them mount it in place.Cut the pins at the end.

Step 6: Make the Necessary Connections

  1. Solder the power lines from the terminal to the regulator;
  2. Solder the led;
  3. Connect the arduino GND --> Switch --> Regulator GND OUT-;
  4. Connect Regulator OUT+ to arduino 5v( I connected the Vcc and then to arduino 5v);
  5. Solder the transistor, mosfet or relay( for the transistor the base resistor regulate the speed of the motor);
  6. Connect the pins for the level probes(right down in the picture) and moisture level connector (left down in the last picture);
  7. Connect power and ground lines, analog inputs and level probe resistor to the ground as in the schematic;

Step 7: Getting an Enclosure

To keep all the parts together you need an enclosure. My dad helped to do one from wood and plywood.

The case consist in two plywood rectangles and a frame between them.The front holes are for the led and sensor cables to pass through and cutouts in the sides for power, motor cable and switch.

Step 8: Make the Cables

You can use any wires for the sensors because are low powered but for motor you need thicker wires. You can use cables like phone cable with 4 wires for sensors(i used separated wires twisted with a drill) and cable for subwoofer for motor and level probes. Add headers and use individual heatshrink tube and insulating tape to protect it from water.

Step 9: Making Water Level Probes

For level probes I opened empty 1.5 volt big battery( even if is not recommended) because graphite is very resistant and you can find it connected to the + side into the metal cap.I drilled 3 mm hole and inserted 2 mm wire with isolation and make a V that is being blocked inside .After this you need to seal the gaps wit silicone or superglue;

This method can be used for sensor soil moisture probe but you should use something with lower resistance( like the rod inside a pencil).

Step 10: Code and Conclusion

To sum up I recommend to try making an instructable because all of us can learn something new from others.This is first time when I write an article in English so probably I did mistakes but I try to learn something new.

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