Automatic Plant Watering Device

My project is an automatic plant watering device, to help me with watering the plants at home. It use the moisture sensor and the water level sensor, and a pump to send water to the plant.


Jihang Li

Area of Interest

ie Electrical Engineering


Mission San Jose High School


Incoming Sophomore

In this two weeks of time in bluestamp, I learned a lot, when I’m first came in bluestamp, I knows nothing about

Final Milestone

In this milestone, I added a pot and a new container to my device. On the new container, I cut a hole on top so the plastic pipe can stick out. I put my pump and water level sensor in it. Now I am able to place my moisture sensor in the pot, and connect the pipe to the pot so that the pump can water the plant. Before, I only had a plastic water bottle and a small pot without plant in it. Now everything is organised. I didn’t have enough time to solder all the component on the PCB , so I left it on a breadboard instead.

Third Milestone

This is my third milestone. In this milestone, I connected the moisture sensor to the pump, so that the pump will open or close based on the reading of the moisture sensor. When the moisture level is below 400, the pump will open and send water to the pot for 2 seconds, then the pump will close. The pump will repeat this process until the moisture level reaches 400. I used an N-channel MOSFET to power the pump and added a 10k resister and a diode to protect the pump. I faced a lot of problems during the process. At first the pump was not working, so I thought that my battery didn’t have enough current to power up the pump. But after I changed my battery, the pump was still not working. Then I thought that maybe it was the problem with the wire. So I soldered the wire together and my pump was finally working. So now I can make the whole system work and actually water plants.

Second Milestone

My second milestone is connecting the buzzer to the water sensor and adding my moisture sensor back on. The moisture sensor is used to measure the water content of soil. When the soil is having a water shortage, the module output reads at a high level, else the output reads at a low level. I’m using a piezo buzzer, it’s a type of audio signalling device. The piezo buzzer produces sound based on the inverse of the piezoelectric effect, an exchange between mechanical energy and electric energy. When the readings of the sensor are below 550, that means the water level is below 2 cm. Then the buzzer will make a sound and the LED will turn red. Otherwise the buzzer will stop and the LED will turn green. Also the reading of the moisture sensor will show on the serial monitor. I was facing some problems during this process. My buzzer makes a sound when the water sensor reading is above 550, which is not what I planned. Soon I found out that the VCC and GND connections were reversed. So I fixed that and now the buzzer finally works

First Milestone

My first mile stone is connecting the water sensor to the nano board and setting up the RGB LED to monitor the water level. At first, I was thinking of using the LED to monitor the moisture level, but I figured that the water level is more important, so I decided to do the water level sensor first. I made the LED turn red when the water sensor reads below 600. When the water sensor reads above 600, the light will turn green. At first, I could not find the right port to upload the code to, so I needed to check the type of the USB port and download the driver so I could upload my code to the board. Another problem I faced is when the sensor read above 600, the LED would turn off instead of turning green. I soon solved the problem, the wire that connects the board and the green light was not working. So I changed the wire and now it works.

Starter Project

My starter project is the Simon Says game. This device creates a series of tones and lights and requires the user to repeat the sequence. When you press a wrong button, the buzzer will ring and the lights will flash. This device is powered by two AA batteries. During the project, I learned about the resistors and the capacitors. Resistors reduce the current flow and capacitors store electricity. I also struggled on soldering different components of the device. It was the first time I have soldered so I made a few mistakes and I needed to desolder them which was difficult. The microcontroller was the hardest part to solder. It’s an important part that acts like a computer which can control the device. Although it’s the first time I soldered for a project, I finished without many issues.
Starter Project

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