SoilBot.ino

/*  Soil Moisture Device
    Written by Coty Beasley
    https://coty.design

    Project started: Feb 2019
    Project repo: https://github.com/beacrea/SoilBot
*/
/********************************************************
 Libraries
 *******************************************************/
#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>

// Define variables
#define I2C_ADDR          0x27 // Define I2C Address where the PCF8574A is
#define BACKLIGHT_PIN      3
#define En_pin             2
#define Rw_pin             1
#define Rs_pin             0
#define D4_pin             4
#define D5_pin             5
#define D6_pin             6
#define D7_pin             7

// Rather than powering the sensor through the 3.3V or 5V pins,
// we'll use a digital pin to power the sensor. This will
// prevent corrosion of the sensor as it sits in the soil.

// Declare a variable for the soil moisture sensor
int soilPin = A0;

// Variable for Soil moisture Power
int soilPower = 7;

// Set initial moisture value
int moistureVal = 0;

// Sets initial message
String valueMessage = "";

/********************************************************
 Calibration
 *******************************************************/
int moistureCeiling = 870;
int moistureFloor = 500;

// Initialise the LCD
LiquidCrystal_I2C      lcd(I2C_ADDR, En_pin, Rw_pin, Rs_pin, D4_pin, D5_pin, D6_pin, D7_pin);

// Custom Characters
byte heart[] = {
  B00000,
  B00000,
  B01010,
  B11111,
  B01110,
  B00100,
  B00000,
  B00000
};

byte degree[] = {
  B01110,
  B01010,
  B01110,
  B00000,
  B00000,
  B00000,
  B00000,
  B00000
};

byte flower[] = {
  B01010,
  B01110,
  B11111,
  B01110,
  B00100,
  B00100,
  B01110,
  B01110
};

byte sun[] = {
  B10101,
  B01110,
  B11011,
  B01110,
  B10101,
  B00000,
  B00000,
  B00000
};

byte drop[] = {
  B00100,
  B00100,
  B01110,
  B01110,
  B11111,
  B11111,
  B01110,
  B00000
};

byte cactus[] = {
  B00100,
  B01100,
  B01100,
  B01101,
  B11111,
  B01100,
  B01100,
  B01100
};

byte smile[] = {
  B00000,
  B01110,
  B10101,
  B11111,
  B10101,
  B11011,
  B01110,
  B00000
};

byte bone[] = {
  B00000,
  B01010,
  B01110,
  B00100,
  B00100,
  B01110,
  B01010,
  B00000
};

byte frown[] = {
  B00000,
  B01110,
  B10101,
  B11111,
  B11011,
  B10101,
  B01110,
  B00000
};

byte glassLow[] = {
  B00000,
  B01010,
  B01010,
  B01010,
  B01010,
  B01110,
  B01110,
  B00000
};


/********************************************************
 Setup
 *******************************************************/
void setup()
{
  Serial.begin(9600); // Open serial over USB
  delay(500); // Wait for display to boot up

  pinMode(soilPower, OUTPUT); // Set D7 as an OUTPUT
  digitalWrite(soilPower, LOW); // Set to LOW so no power is flowing through the sensor

  // Define the LCD as 16 column by 2 rows
  lcd.begin (20, 4);

  // Create custom character
  lcd.createChar(1, heart);
  lcd.createChar(2, glassLow);
  lcd.createChar(3, flower);
  lcd.createChar(4, sun);
  lcd.createChar(5, drop);
  lcd.createChar(6, cactus);
  lcd.createChar(7, smile);
  lcd.createChar(8, bone);

  // Switch on the backlight
  lcd.setBacklightPin(BACKLIGHT_PIN, POSITIVE);
  lcd.setBacklight(HIGH);

  // First line
  lcd.setCursor(0, 0);
  for (int i = 1; i <= 20; i++) {
    lcd.write(4);
  }

  // Goto first column (column 0) and second line (Line 0)
  lcd.setCursor(0, 1);
  lcd.print("SoilBot is online ");
  lcd.write(1);
  lcd.print("!");

  // Third line
  lcd.setCursor(0, 2);
  for (int i = 1; i <= 10; i++) {
    lcd.print("-.");
  }

  // Last line
  lcd.setCursor(0, 3);
  for (int i = 1; i <= 20; i++) {
    lcd.write(3);
  }

  // Hold before running
  delay(4000);
}

/********************************************************
 Main Loop
 *******************************************************/
void loop()
{
  // Here we are declaring a string, which are lines of words,
  // and we want DisplayWords to be the words displayed on
  // the LCD screen, which will change based on whether the soil
  // wet or dry based on our threshold values above.
  String DisplayWords;

  // We need to set up a pin to get the value that the soil
  // moisture sensor is outputting, so sensorValue will get the
  // analog value from the sensor pin A0 on the redboard that we
  // set up earlier.

  int sensorValue;

  // Animation
  runAnimation();
  delay(2000);

  // Run Measurement
  readSoil();
  
  // Display value
  lcd.clear();
  lcd.setCursor(0, 1);
  lcd.print("Moisture: ");
  lcd.print(moistureVal);
  lcd.setCursor(0, 0);
  for (int i = 1; i <= 20; i++) {
    lcd.print("-");
  }
  lcd.setCursor(0, 2);
  translateValue();
  lcd.setCursor(0, 3);
  for (int i = 1; i <= 20; i++) {
    lcd.print("-");
  }

  // Serial output
  Serial.print("Soil Moisture: ");
  Serial.println(moistureVal);
  
  // Delay until next reading. Set for 15 min.
  delay(900000);
}


/********************************************************
 Animation
 *******************************************************/
void runAnimation() {
  // First frame
  lcd.setCursor(0, 0);
  for (int i = 1; i <= 10; i++) {
    lcd.write(5);
    lcd.print(" ");
  }
  lcd.setCursor(0, 1);
  for (int i = 1; i <= 10; i++) {
    lcd.print(" ");
    lcd.write(5);
  }
  lcd.setCursor(0, 2);
  for (int i = 1; i <= 10; i++) {
    lcd.write(5);
    lcd.print(" ");
  }
  lcd.setCursor(0, 3);
  for (int i = 1; i <= 10; i++) {
    lcd.print(" ");
    lcd.write(5);
  }

  // Delay
  delay(1000);

  // Second Frame
  lcd.setCursor(0, 0);
  for (int i = 1; i <= 10; i++) {
    lcd.print(" ");
    lcd.write(5);
  }
  lcd.setCursor(0, 1);
  for (int i = 1; i <= 10; i++) {
    lcd.write(5);
    lcd.print(" ");
  }
  lcd.setCursor(0, 2);
  for (int i = 1; i <= 10; i++) {
    lcd.print(" ");
    lcd.write(5);
  }
  lcd.setCursor(0, 3);
  for (int i = 1; i <= 10; i++) {
    lcd.write(5);
    lcd.print(" ");
  }
}

/********************************************************
 Soil Measurement
 *******************************************************/
int readSoil()
{
  // Reset moisture
  moistureVal = 0;
  
  // Turn D7 "On"
  digitalWrite(soilPower, HIGH);

  // Wait 10 milliseconds
  delay(10);

  // Read the SIG value form sensor
  moistureVal = analogRead(soilPin);

  // Turn D7 "Off"
  digitalWrite(soilPower, LOW);

  // Send current moisture value
  return moistureVal;
}

/********************************************************
 Result Synthesis
 *******************************************************/
String translateValue() {
  if (moistureVal > moistureCeiling) {
    lcd.write(5);
    lcd.write(5);
    lcd.write(5);
    lcd.print(" ");
    lcd.print("Too much water!");
  }
  else if (moistureVal < moistureCeiling && moistureVal > (moistureCeiling*0.75)) {
    lcd.write(3);
    lcd.write(3);
    lcd.write(3);
    lcd.print(" ");
    lcd.print("Doing great");
  }
  else if (moistureVal <= moistureFloor && moistureVal > (moistureFloor)) {
    lcd.write(2);
    lcd.write(2);
    lcd.write(2);
    lcd.print(" ");
    lcd.print("Need some water");
  }
  else {
    lcd.write(8);
    lcd.write(8);
    lcd.write(8);
    lcd.print(" Dry as bones!");
  }
  return valueMessage;
}