Automatic Garden Watering Device – Arduino

Thankfully we have some resources online that provide us with most of the code, we just have to get it to work together.

This is the code for the Sunkee Sensor from Steve Spence’s Blog

//The (int soil=0) is the soil variable which turns the reading that comes in on the sensor into a %, this will be an important variable in this project

int soil=0;

// the setup routine runs once when you press reset, and sets up communication with the serial port:

void setup() {

// initialize serial communication at 9600 bits per second:

Serial.begin(9600);}

// the loop routine runs over and over again forever:

void loop() {// read the input on analog pin 0:

int sensorValue = analogRead(A0);

sensorValue = constrain(sensorValue, 485, 1023);

// print out the value you read:

//Serial.println(sensorValue);

//map the value to a percentage

soil = map(sensorValue, 485, 1023, 100, 0);

// print out the soil water percentage you calculated:

Serial.print(soil);

Serial.println(“%”);

delay(1000); // delay in between reads for stability, the delay is in millieseconds so this is a 1 second delay}

The following is public domain code used from the Arduino website. This code sends whatever message we want to the LCD Screen. In this instance it displays “Hello World” on the first line and a count of the seconds since reset on the second.

#include

// initialize the library with the numbers of the interface pins

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {// set up the LCD’s number of columns and rows:

lcd.begin(16, 2);

// Print a message to the LCD.

lcd.print(“hello, world!”);}

void loop() {

// set the cursor to column 0, line 1

// (note: line 1 is the second row, since counting begins with 0):

lcd.setCursor(0, 1);

// print the number of seconds since reset:

lcd.print(millis()/1000);}

The next step is to modify those two pieces of code and then put a loop in it that will turn on the relay when soil moisture falls to a certain point. When that is all said and done, it looks like this:

//This first section sets up our variables and initializes the LCD screen

int soil=0;
int Relay = 7;

int relay_level=60;

#include

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // the setup routine runs once when you press reset:

void setup() {// initialize serial communication at 9600 bits per second:

Serial.begin(9600); // set up the LCD’s number of columns and rows:}

// the loop routine runs over and over again forever:

void loop() {// read the input on analog pin 0:

int sensorValue = analogRead(A0);

sensorValue = constrain(sensorValue, 485, 1023);

// print out the value you read: Serial.println(sensorValue);

// initialize the digital pin as an output.

pinMode(Relay, OUTPUT);

//map the value to a percentage

soil = map(sensorValue, 485, 1023, 100, 0);

// print out the soil water percentage you calculated to the LCD Screen:

Serial.print(soil);

Serial.println(“%”);

// set the cursor to column 0, line 1

// (note: line 1 is the second row, since counting begins with 0):

lcd.begin(16, 2);

// Print a message to the LCD.

lcd.clear();

lcd.print(“Soil Saturation:”);

lcd.setCursor(0, 1);

// print the number of seconds since reset:

lcd.print(soil);

lcd.print (“%”);

// delay in between reads for stability

delay(1000);

// This next loop turns on the relay for one minute if the moisture is below the level we want (in this case 60%), if the moisture is above that level, it keeps testing. If the level of moisture is below that level it turns the relay (and subsequently the water valve for as long as you would like (in this case it is set for 60000 milliseconds (1 minute)). It then waits another minute before testing the soil again in order to see if it is wet enough.

if (soil < relay_level) {digitalWrite(Relay, HIGH);

// turn the Relay on (HIGH is the voltage level)

delay(60000);

// wait for a minute

digitalWrite(Relay, LOW);

// turn the LED off by making the voltage LOW

delay(60000);

// wait for a minute}}

Step 8: We then compile the code from the Arudino window and send it to the board.