Chathuranga Liyanage
Published © GPL3+

Portable Environment Monitor

A handheld monitor for young scientists to get familiar with various aspects of the surrounding environment.

IntermediateFull instructions provided5 hours1,906

Things used in this project

Hardware components

Arduino 101 & Genuino 101
Arduino 101 & Genuino 101
×1
Grove - Light Sensor
Seeed Grove - Light Sensor
×1
DHT11 Temperature & Humidity Sensor (4 pins)
DHT11 Temperature & Humidity Sensor (4 pins)
×1
Sparkfun Sound Detector
×1
Seeed Grove LCD
×1
SparkFun Soil Moisture Sensor (with Screw Terminals)
SparkFun Soil Moisture Sensor (with Screw Terminals)
×1
Seeed Grove Button
×1
Seeed Grove universal cables
×1
Base Shield V2
Seeed Base Shield V2
×1

Software apps and online services

Arduino IDE
Arduino IDE

Story

Read more

Code

Basic_1.ino

Arduino
 #include <Adafruit_Sensor.h>
#include "DHT.h"         //include DHT library
#define DHTPIN 3         //define as DHTPIN the Pin 3 used to connect the Sensor
#define DHTTYPE DHT11    //define the sensor used(DHT11)
#define light A0
#define noise A1
#define moist A2
#define button 8
DHT dht(DHTPIN, DHTTYPE);//create an instance of DHT
#include <Wire.h>
#include "rgb_lcd.h"
#include "math.h"

rgb_lcd lcd;

const int colorR = 0;
const int colorG = 30;
const int colorB = 55;

int page = 0;

void setup() 
{
    // set up the LCD's number of columns and rows:
    Serial.begin(9600);
    lcd.begin(16, 2);
    dht.begin(); 
    lcd.setRGB(colorR, colorG, colorB);
    pinMode(light,INPUT);
    pinMode(noise,INPUT);
    pinMode(button,INPUT);
    pinMode (2,OUTPUT);
    pinMode (A3,OUTPUT);
    digitalWrite(2,HIGH);
    digitalWrite(A3,OUTPUT);
    pinMode (1,OUTPUT);
}

void loop() 
{
    while (page == 0){
      first_page();
      if (digitalRead(button) == 1)
         page++;
    }
    delay(500);
    while (page == 1){
      second_page();
      if (digitalRead(button) == 1)
          page++;
    }
    delay(500);

    while (page == 2){
      third_page();
      if (digitalRead(button) == 1)
          page = 0;
    }

    delay(500);

}

void first_page(){

  int h = dht.readHumidity();    // reading Humidity 
    int t = dht.readTemperature();
    int light_l = 0;
    
    for (int x=0; x<50;x++){
      light_l = light_l + analogRead(light);
      delay(2);
    }

    light_l = light_l/50;
    lcd.setCursor(12, 1);
    lcd.print("  lx");
    lcd.setCursor(0, 0);
    lcd.print("Temp ");
    lcd.setCursor(0, 1);
    lcd.print(t);
    lcd.setCursor(2, 1);
    lcd.print("_C ");
    
    lcd.setCursor(5, 0);
    lcd.print("Humid");
    lcd.setCursor(6, 1);
    lcd.print(h);
    lcd.setCursor(8, 1);
    lcd.print("%");
    
    lcd.setCursor(11, 0);
    lcd.print("Light");
    lcd.setCursor(11, 1);
    lcd.print(light_l);
  
}
void second_page(){

    int sound = 0;
    for(int x = 0;x<10;x++){
          sound = sound + analogRead(noise);
    }
    sound = sound/10;
    double dB = 20*(log10(10*sound)) ;
    lcd.setCursor(0, 0);
    lcd.print("Noise           ");
    lcd.setCursor(0, 1);
    lcd.print(dB);
    lcd.setCursor(5, 1);
    lcd.print("            ");
    delay(100);
  
}

void third_page(){
  int moist_s = 0;

  for (int y = 0; y<100 ; y++){
    moist_s = moist_s + analogRead(moist);
    delay(2);
  }

  moist_s = moist_s/100;
  lcd.setCursor(0,0);
  lcd.print("Water- ");
  lcd.setCursor(0,1);
  lcd.print("Soil- ");

  lcd.setCursor(6,1);
  if(moist_s>900) lcd.print("Dry    ");
  else if(moist_s>650) lcd.print("Medium");
  else lcd.print("High   ");

  lcd.setCursor(7,0);
  if(moist_s>750) lcd.print("No      ");
  else if(moist_s>600) lcd.print("Distill ");
  else if(moist_s>500) lcd.print("Drinking");
  else if(moist_s>350) lcd.print("Fish    ");
  else lcd.print("Polluted");

}

DHT11.ino

Arduino
// DHT11 Temperature and Humidity Sensors Example
 #include <Adafruit_Sensor.h>
#include "DHT.h"         //include DHT library
#define DHTPIN 3         //define as DHTPIN the Pin 3 used to connect the Sensor
#define DHTTYPE DHT11    //define the sensor used(DHT11)
DHT dht(DHTPIN, DHTTYPE);//create an instance of DHT
/*setup*/
void setup() {
  Serial.begin(9600);    //initialize the Serial communication
  delay(6000);           //wait 6 seconds
  Serial.println("Temperature and Humidity test!");//print on Serial monitor
  Serial.println("T(C) \tH(%)");                   //print on Serial monitor
  dht.begin();           //initialize the Serial communication
}
/*loop*/
void loop() {
 
  float h = dht.readHumidity();    // reading Humidity 
  float t = dht.readTemperature(); // read Temperature as Celsius (the default)
  // check if any reads failed and exit early (to try again).
    if (isnan(h) || isnan(t)) {    
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  Serial.print(t, 2);    //print the temperature
  Serial.print("\t");
  Serial.println(h, 2);  //print the humidity
  delay(500);           //wait 2 seconds
}

Kalman.h

C/C++
/* Copyright (C) 2012 Kristian Lauszus, TKJ Electronics. All rights reserved.

 This software may be distributed and modified under the terms of the GNU
 General Public License version 2 (GPL2) as published by the Free Software
 Foundation and appearing in the file GPL2.TXT included in the packaging of
 this file. Please note that GPL2 Section 2[b] requires that all works based
 on this software must also be made publicly available under the terms of
 the GPL2 ("Copyleft").

 Contact information
 -------------------

 Kristian Lauszus, TKJ Electronics
 Web      :  http://www.tkjelectronics.com
 e-mail   :  kristianl@tkjelectronics.com
 */

#ifndef _Kalman_h
#define _Kalman_h

class Kalman {
public:
    Kalman() {
        /* We will set the variables like so, these can also be tuned by the user */
        Q_angle = 0.01;//0.001
        Q_bias = 0.0001;//0.003
        R_measure = 0.11;//0.03

        angle = 0; // Reset the angle
        bias = 0; // Reset bias

        P[0][0] = 0; // Since we assume that the bias is 0 and we know the starting angle (use setAngle), the error covariance matrix is set like so - see: http://en.wikipedia.org/wiki/Kalman_filter#Example_application.2C_technical
        P[0][1] = 0;
        P[1][0] = 0;
        P[1][1] = 0;
    };
    // The angle should be in degrees and the rate should be in degrees per second and the delta time in seconds
    double getAngle(double newAngle, double newRate, double dt) {
        // KasBot V2  -  Kalman filter module - http://www.x-firm.com/?page_id=145
        // Modified by Kristian Lauszus
        // See my blog post for more information: http://blog.tkjelectronics.dk/2012/09/a-practical-approach-to-kalman-filter-and-how-to-implement-it

        // Discrete Kalman filter time update equations - Time Update ("Predict")
        // Update xhat - Project the state ahead
        /* Step 1 */
        rate = newRate - bias;
        angle += dt * rate;

        // Update estimation error covariance - Project the error covariance ahead
        /* Step 2 */
        P[0][0] += dt * (dt*P[1][1] - P[0][1] - P[1][0] + Q_angle);
        P[0][1] -= dt * P[1][1];
        P[1][0] -= dt * P[1][1];
        P[1][1] += Q_bias * dt;

        // Discrete Kalman filter measurement update equations - Measurement Update ("Correct")
        // Calculate Kalman gain - Compute the Kalman gain
        /* Step 4 */
        S = P[0][0] + R_measure;
        /* Step 5 */
        K[0] = P[0][0] / S;
        K[1] = P[1][0] / S;

        // Calculate angle and bias - Update estimate with measurement zk (newAngle)
        /* Step 3 */
        y = newAngle - angle;
        /* Step 6 */
        angle += K[0] * y;
        bias += K[1] * y;

        // Calculate estimation error covariance - Update the error covariance
        /* Step 7 */
        P[0][0] -= K[0] * P[0][0];
        P[0][1] -= K[0] * P[0][1];
        P[1][0] -= K[1] * P[0][0];
        P[1][1] -= K[1] * P[0][1];

        return angle;
    };
    void setAngle(double newAngle) { angle = newAngle; }; // Used to set angle, this should be set as the starting angle
    double getRate() { return rate; }; // Return the unbiased rate

    /* These are used to tune the Kalman filter */
    void setQangle(double newQ_angle) { Q_angle = newQ_angle; };
    void setQbias(double newQ_bias) { Q_bias = newQ_bias; };
    void setRmeasure(double newR_measure) { R_measure = newR_measure; };

    double getQangle() { return Q_angle; };
    double getQbias() { return Q_bias; };
    double getRmeasure() { return R_measure; };

private:
    /* Kalman filter variables */
    double Q_angle; // Process noise variance for the accelerometer
    double Q_bias; // Process noise variance for the gyro bias
    double R_measure; // Measurement noise variance - this is actually the variance of the measurement noise

    double angle; // The angle calculated by the Kalman filter - part of the 2x1 state vector
    double bias; // The gyro bias calculated by the Kalman filter - part of the 2x1 state vector
    double rate; // Unbiased rate calculated from the rate and the calculated bias - you have to call getAngle to update the rate

    double P[2][2]; // Error covariance matrix - This is a 2x2 matrix
    double K[2]; // Kalman gain - This is a 2x1 vector
    double y; // Angle difference
    double S; // Estimate error
};

#endif

Final Code

Arduino
#include <Adafruit_Sensor.h>
#include "DHT.h"         //include DHT library
#define DHTPIN 3         //define as DHTPIN the Pin 3 used to connect the Sensor
#define DHTTYPE DHT11    //define the sensor used(DHT11)
#define light A0
#define noise A1
#define moist A2
#define button 8
DHT dht(DHTPIN, DHTTYPE);//create an instance of DHT
#include <Wire.h>
#include "rgb_lcd.h"
#include "math.h"
#include <CurieIMU.h>
#include "Kalman.h"

Kalman kalmanX; // Create the Kalman instances
Kalman kalmanY;

float accX, accY, accZ;
float gyroX, gyroY, gyroZ;

double gyroXangle, gyroYangle; 
double compAngleX, compAngleY; 
double kalAngleX, kalAngleY; 

rgb_lcd lcd;
uint32_t timer;

const int colorR = 0;
const int colorG = 30;
const int colorB = 55;

int page = 0;

void setup() 
{
    // set up the LCD's number of columns and rows:
    Serial.begin(9600);
    lcd.begin(16, 2);
    dht.begin(); 
    lcd.setRGB(colorR, colorG, colorB);
    pinMode(light,INPUT);
    pinMode(noise,INPUT);
    pinMode(button,INPUT);
    pinMode (2,OUTPUT);
    pinMode (A3,OUTPUT);
    digitalWrite(2,HIGH);
    digitalWrite(A3,OUTPUT);
    pinMode (1,OUTPUT);
  CurieIMU.begin();
  CurieIMU.setAccelerometerRange(2);
  CurieIMU.setGyroRange(250);
  delay(100); // Wait for sensor to stabilize
  CurieIMU.readAccelerometerScaled(accX, accY, accZ);

  double roll  = atan2(accY,accZ) * RAD_TO_DEG;
  double pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
  //double yaw = atan (accZ/sqrt(accX*accX + accZ*accZ)) * RAD_TO_DEG;
  kalmanX.setAngle(roll); // Set starting angle
  kalmanY.setAngle(pitch);
  gyroXangle = roll;
  gyroYangle = pitch;
}

void loop() 
{
    while (page == 0){
      first_page();
      if (digitalRead(button) == 1)
         page++;
    }
    delay(500);
    while (page == 1){
      second_page();
      if (digitalRead(button) == 1)
          page++;
    }
    delay(500);

    while (page == 2){
      third_page();
      if (digitalRead(button) == 1)
          page = 0;
    }

    delay(500);

}

void first_page(){

  int h = dht.readHumidity();    // reading Humidity 
    int t = dht.readTemperature();
    int light_l = 0;
    
    for (int x=0; x<50;x++){
      light_l = light_l + analogRead(light);
      delay(2);
    }

    light_l = light_l/50;
    lcd.setCursor(12, 1);
    lcd.print("  lx");
    lcd.setCursor(0, 0);
    lcd.print("Temp ");
    lcd.setCursor(0, 1);
    lcd.print(t);
    lcd.setCursor(2, 1);
    lcd.print("_C ");
    
    lcd.setCursor(5, 0);
    lcd.print("Humid");
    lcd.setCursor(6, 1);
    lcd.print(h);
    lcd.setCursor(8, 1);
    lcd.print("%");
    
    lcd.setCursor(11, 0);
    lcd.print("Light");
    lcd.setCursor(11, 1);
    lcd.print(light_l);
  
}
void second_page(){

    int sound = 0;
    for(int x = 0;x<10;x++){
          sound = sound + analogRead(noise);
    }
    sound = sound/10;
    double dB = 20*(log10(10*sound)) ;
    lcd.setCursor(0, 0);
    lcd.print("Noise ");
    lcd.setCursor(0, 1);
    lcd.print(dB,0);
    lcd.setCursor(2, 1);
    lcd.print("dB");
    lcd.setCursor(6, 0);
    lcd.print("Roll ");
    lcd.setCursor(11, 0);
    lcd.print("Pitch");
    
for (int z=0; z<10;z++){

CurieIMU.readAccelerometerScaled(accX, accY, accZ); 
CurieIMU.readGyroScaled(gyroX, gyroY, gyroZ);

double dt = (double)(micros() - timer) / 1000000; // Calculate delta time
timer = micros();
 

double roll  = atan2(accY,accZ) * RAD_TO_DEG;
double pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
//double yaw = atan2(accZ,sqrt(accX*accX + accZ*accZ)) * RAD_TO_DEG;


  double gyroXrate = gyroX / 131.0; // Convert to deg/s
  double gyroYrate = gyroY / 131.0; // Convert to deg/s

  if ((roll < -90 && kalAngleX > 90) || (roll > 90 && kalAngleX < -90)) {
    kalmanX.setAngle(roll);
    compAngleX = roll;
    kalAngleX = roll;
    gyroXangle = roll;
  } else
    kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter

  if (abs(kalAngleX) > 90)
    gyroYrate = -gyroYrate; // Invert rate, so it fits the restriced accelerometer reading
  kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt);

    gyroXangle += gyroXrate * dt; // Calculate gyro angle without any filter
  gyroYangle += gyroYrate * dt;
  //gyroXangle += kalmanX.getRate() * dt; // Calculate gyro angle using the unbiased rate
  //gyroYangle += kalmanY.getRate() * dt;

  compAngleX = 0.93 * (compAngleX + gyroXrate * dt) + 0.07 * roll; // Calculate the angle using a Complimentary filter
  compAngleY = 0.93 * (compAngleY + gyroYrate * dt) + 0.07 * pitch;

  if (gyroXangle < -180 || gyroXangle > 180)
    gyroXangle = kalAngleX;
  if (gyroYangle < -180 || gyroYangle > 180)
    gyroYangle = kalAngleY;

   delay(10); 
}

    lcd.setCursor(10,1);
    lcd.print("  ");
    lcd.setCursor(6,1);
    lcd.print(kalAngleX,1);
    lcd.setCursor(15,1);
    lcd.print(" ");
    lcd.setCursor(12,1);
    lcd.print(kalAngleY,1);
    
  
}

void third_page(){
  int moist_s = 0;

  for (int y = 0; y<100 ; y++){
    moist_s = moist_s + analogRead(moist);
    delay(2);
  }

  moist_s = moist_s/100;
  lcd.setCursor(0,0);
  lcd.print("Water- ");
  lcd.setCursor(0,1);
  lcd.print("Soil- ");

  lcd.setCursor(6,1);
  if(moist_s>900) lcd.print("Dry       ");
  else if(moist_s>650) lcd.print("Medium");
  else lcd.print("High   ");

  lcd.setCursor(7,0);
  if(moist_s>750) lcd.print("No       ");
  else if(moist_s>600) lcd.print("Distill ");
  else if(moist_s>500) lcd.print("Drinking");
  else if(moist_s>350) lcd.print("Fish    ");
  else lcd.print("Polluted");

}

Credits

Chathuranga Liyanage

Chathuranga Liyanage

4 projects • 17 followers
Undergraduate in Electronic and Telecommunication Engineering

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