DIY Solar Powered Garden Watering System

Automating every day tasks are the best projects for so many reasons. You can find a real problem and take it as a challenge to automate it. In the end you will end up with plenty of new knowledge, practical experience with problem solving and more time for new projects because a new project will take care of the every day task. Simple and really rewarding project of this kind is an automated watering system add to that solar power and you have a perfect solution!

To learn more about the project, how I built it, problems I faced and how it works take a look at this video:


Here is a list of parts you will need to build a Pico watering system. You cna find all the files for both systems on my GitHub, links at the end of this page.

Raspberry Pi Pico
Solar panel and charger
Garden irrigation system
Water level sensor

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Two systems

My plan was to build a watering system with a few sensors just for fun. While building it I started adding more and more sensors and ended up with a pretty sophisticated system. Also I wanted to make this project in a good old DIY fashion to make it easy for everyone to replicate. In the end I wasn’t quite happy with the system as it was too complicated, there was too many cables everywhere and it wasn’t simple enough to be elegant.


It’s important to mention that this first system was working great for 11 days and was perfectly watering my garden. Unfortunately the power consumption was pretty high because of many LEDs I had there so it would only work for a few more cloudy days before running out of battery. My DIY soil moisture sensors weren’t working reliably and after creating the plots all the sensors weren’t really needed anymore. All I needed was a simple watering system.

My DIY soil moisture sensor

It obviously wasn’t a waste of time because I learned a lot while making this first version of the system and I used that experience while making the second one. Also with the data collected over 11 days I made some cool looking plots. There is a vertical line every 86 milion milliseconds (that’s 24 hours) so we can see that we have data from almost full 11 days. It was collected during a heatwave in Poland (that was quite fortunate because the system was able to charge fully during the day to survive the night).

Ground and air temperature plots over 11 days of the test

Here we can see sudden drops in the data from ground moisture sensors, unfortunately it is caused by a voltage drop on the battery when turning on the pump. Based on these plots we can conclude that these sensors weren’t working properly. I hope to try to build my own capacitive moisture sensor soon.

Ground moisture data from DIY resistive sensors that unfortunately weren’t working properly
Sunlight data

Here we can see nice correlation between the plots above and below. It’s also visible that the solar charging system wasn’t big enough and wasn’t able to charge the battery on a cloudy day and it got discharged significantly. That’s why reducing power consumption in such systems is really important.

Voltage on a battery

For that reason I decided to start all over again and design a new simple system with only necessary components that consumes less current, is easier to build and more elegant. This time instead of using Arduino (Arduino is great and I still love it but sometimes it’s nice to experiment and try something new) I used Raspberry Pi Pico a microcontroller based board from Raspberry Pi based on RP2040 chip. It’s incredibly chip for what it can offer and is programmed in Python. It’s not the best choice for extreme low power solutions but I am using here a 12V 4Ah battery with a 10W solar panel so that’s not the most important factor for me. RP2040 chip itself is low cost compared to other solutions and what’s really important these days (July 2022) is available. Adding to that a 7805 voltage regulator, IRFZ44N MOSFETs, buttons and a few LEDs I designed a simple single sided PCB – single sided means easy to make at home. To make it I used a $200 CNC machine.

Machining a PCB on a $200 CNC machine with a really nice result
Final PCB for Pico watering system

There is two of everything on the PCB so you can run two separate systems for different parts of the garden (it’s not yet implemented in the program). With two buttons and 8 LEDs you can easily set number of watering cycles per day (between 1 and 4) and watering cycle time (you can choose from 2, 4, 6 and 8 minutes per cycle) of course that can be also adjusted in the program depending on what you need in your garden. Settign are stored in the flash memory of the Pico, it’s amazing that you can simply safe a file there as you would in a normal Python running on your computer!

Simple LED and buttons make can make a great user interface

Case was 3D printed with PETG on Ender3 and additionally closed in a 2l food container together with the battery to protect it. I also used cable gland to go with the cables through the container. In the end everything was attached to a a wooden pole and solar panel got pointed south for maximum efficiency. I used a 150l water reservoir that honestly after testing it for two weeks is a bit small and something closer to 300l would be great. Also a rain water collection system could help here significantly.


You can find all the files for this project on my GitHub:

Here is a link to the Pico watering system:

And here is a link to the WDCS (Watering and Data Collection System):

Feel free to ask any questions, share the video and contribute to the open source project!

Happy making and have a nice day!

Arduino Based Air Quality Monitor

The air quality is a pretty big problem in my city. We have a monitoring station but it’s quite far from where I live so I decided to build myself a local, simple and nice-looking air quality monitor. You can learn more about the whole project and how I made it in this video:

Below you can find all the files and code for the project. And here are the parts that I used:

Arduino Nano
Air Quality Sensor
NeoPixel Ring


#include <Adafruit_NeoPixel.h>
#include <SoftwareSerial.h>

#define LED_PIN 6 
#define SLEEP_PIN 5
#define MAX_PM1_LEVEL 50
#define MAX_PM25_LEVEL 30
#define MAX_PM10_LEVEL 40
#define NUMPIXELS 24 
Adafruit_NeoPixel pixels(NUMPIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);

// 0 - green, 1 - blue, 2- orange, 3 - red
int last_color = 5;

#define LENG 31   //0x42 + 31 bytes equal to 32 bytes
unsigned char buf[LENG];

SoftwareSerial SoftSerial(10, 11); // RX, TX

void setup() {
  pinMode(5, OUTPUT);

void loop() {

digitalWrite(SLEEP_PIN, HIGH);
delay(1000L * 60L);
int pm01_level = 0;
int pm25_level = 0;
int pm10_level = 0;

int air_quality[3];


pm01_level = air_quality[0];
pm25_level = air_quality[1];
pm10_level = air_quality[2];

if(pm01_level < MAX_PM1_LEVEL && pm25_level < MAX_PM25_LEVEL && pm10_level < MAX_PM10_LEVEL){
  if(last_color != 0){
  last_color = 0;
}else if((pm01_level > MAX_PM1_LEVEL && pm25_level < MAX_PM25_LEVEL && pm10_level < MAX_PM10_LEVEL) || (pm01_level < MAX_PM1_LEVEL && pm25_level > MAX_PM25_LEVEL && pm10_level < MAX_PM10_LEVEL) || (pm01_level < MAX_PM1_LEVEL && pm25_level < MAX_PM25_LEVEL && pm10_level > MAX_PM10_LEVEL)){
  if(last_color != 1){
  last_color = 1;
}else if((pm01_level > MAX_PM1_LEVEL && pm25_level > MAX_PM25_LEVEL && pm10_level < MAX_PM10_LEVEL) || (pm01_level > MAX_PM1_LEVEL && pm25_level < MAX_PM25_LEVEL && pm10_level > MAX_PM10_LEVEL) || (pm01_level < MAX_PM1_LEVEL && pm25_level > MAX_PM25_LEVEL && pm10_level > MAX_PM10_LEVEL)){
  if(last_color != 2){
  last_color = 2;
}else if(pm01_level > MAX_PM1_LEVEL && pm25_level > MAX_PM25_LEVEL && pm10_level > MAX_PM10_LEVEL){
  if(last_color != 3){
  last_color = 3;
Serial.print("PM01: ");
Serial.print("PM2.5: ");
Serial.print("PM10: ");

digitalWrite(SLEEP_PIN, LOW);
delay(1000L * 60L * 3L);


void SetColor(int r, int g, int b){
  for(int a = 255; a > 0; a--){
  for(int i = 0; i < NUMPIXELS; i++) { 
    pixels.setPixelColor(i, pixels.Color(r, g, b));;   


void CheckAirQuality(int* air_quality){
  if(SoftSerial.find(0x42)){    //start to read when detect 0x42

    if(buf[0] == 0x4d){
        air_quality[0] = transmitPM01(buf); //count PM1.0 value of the air detector module
        air_quality[1] = transmitPM2_5(buf);//count PM2.5 value of the air detector module
        air_quality[2] = transmitPM10(buf); //count PM10 value of the air detector module

char checkValue(unsigned char *thebuf, char leng)
  char receiveflag=0;
  int receiveSum=0;

  for(int i=0; i<(leng-2); i++){
  receiveSum=receiveSum + 0x42;

  if(receiveSum == ((thebuf[leng-2]<<8)+thebuf[leng-1]))  //check the serial data
    receiveSum = 0;
    receiveflag = 1;
  return receiveflag;

int transmitPM01(unsigned char *thebuf)
  int PM01Val;
  PM01Val=((thebuf[3]<<8) + thebuf[4]); //count PM1.0 value of the air detector module
  return PM01Val;

//transmit PM Value to PC
int transmitPM2_5(unsigned char *thebuf)
  int PM2_5Val;
  PM2_5Val=((thebuf[5]<<8) + thebuf[6]);//count PM2.5 value of the air detector module
  return PM2_5Val;

//transmit PM Value to PC
int transmitPM10(unsigned char *thebuf)
  int PM10Val;
  PM10Val=((thebuf[7]<<8) + thebuf[8]); //count PM10 value of the air detector module
  return PM10Val;

It’s hard to create a nice schematic for this project as there is no Fritzing library for PM2.5 sensor, and I have no idea how to create one 🙂 That’s why below you can find a text only explanation on connection, definitely not a perfect option but at the same time better than nothing:

Air Sensor RXPIN 10
Air Sensor TXPIN 11
Air Sensor 5V5V
Air Sensor GNDGND
Air Sensor SLEEPPIN 5
LED Ring 5V3.3V

As you can see in the table above I connected LED ring 5V to the 3.3V on the Arduino, that’s because there is only one 5V pin on Arduino Nano and it has to be used for Air quality sensor because it doesn’t work with 3.3V.

Thanks a lot for reading and happy making! I hope my air quality sensor will serve you well! And don’t forget to check out my other projects:

Object Tracking Robot – FollowBot V2

This is a second version of original FollowBot made in 2015. This one uses Maix Sipeed board with a camera and LCD screen. With 2 micro servo motors I made a small pan-tilt mechanism. Here you can read some more about how I made this project.

I decided to use new Maix Sipeed board, it’s quite powerful, has build in camera and you can program that in python so I though it should be quite easy to make such project with this board. I was right. If you have at least a little bit of experience with Python and electronics you can do some really cool stuff.

Firstly I had to develop a simple program for tracking red objects. I started by using blob detection algorithm. Basically it searches for all red blobs on the image and store that in a table. Then I had to find the biggest blob as that’s most likely what I want to track (simple for loop with one if statement and one variable can do it). And that’s it, within 40 lines of code you can detect simple single color objects. You can read more about that and find some examples here:


Maix Sipeed
Robot Chassis
Motor Driver

There is no servo library for this board so that’s a downside because you need to figure out on your own how to control a servo (later I noticed that there is a servo example on github linked above). Servo is controlled with 50Hz PWM signal, high signal should be between 1 ms – 2 ms so that’s a duty of 5-10% (5% * 1/50s = 1 ms, 10%*1/50s = 2 ms). With a timer I was able to set up such PWM signal, a simple servo example can be found in all of the files (you can download them at the bottom of the page).

I also designed my own minimal pan and tilt mechanism in Fusion360. STL files are also at the bottom of this page.

I made my own functions to control DC motor driver but that was obviously very easy. Here is how I connected the motor driver and servos to the board.


Maix SipeedDC Motor Driver/Servo
PIN 0Pan Servo Signal
PIN 1Tilt Servo Signal
PIN 9Motor Driver ENA
PIN 10Motor Driver IN1
PIN 11Motor Driver IN2
PIN 12Motor Driver IN3
PIN 13Motor Driver IN4
PIN 14Motor Driver ENB
GNDMotor Driver and Servo GND
5VMotor Driver and Servo 5V

After that I simply connected all small programs that I wrote and put everything on my robot chassis. And it was time for the final test that you can see on the video below.

Here you can find a ZIP archive with all the files including my small subprograms, main and all STL files that you can print. Feel free to edit those and customize this project to make it work for you. Don’t forget to share your work with others and link to my project 🙂

Thanks for reading this short project description, it’s definitely not a full tutorial but I hope it will be helpful for some of you!