/*
  HC-SR04 with Temp and Humidity Demonstration
  HC-SR04-Temp-Humid-Demo.ino
  Demonstrates enhancements of HC-SR04 Ultrasonic Range Finder
  With DHT22 Temperature and Humidity Sensor
  Displays results on Serial Monitor
 
  DroneBot Workshop 2017
  http://dronebotworkshop.com
*/
 
// Include DHT Libraries from Adafruit
// Dependant upon Adafruit_Sensors Library
#include "DHT.h";
 
// Include NewPing Library
#include "NewPing.h"
 
// Define Constants
 
#define DHTPIN 7       // DHT-22 Output Pin connection
#define DHTTYPE DHT22   // DHT Type is DHT 22 (AM2302)
#define TRIGGER_PIN  10
#define ECHO_PIN     13
#define MAX_DISTANCE 400
 
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
 
// Define Variables
 
float hum;    // Stores humidity value in percent
float temp;   // Stores temperature value in Celcius
float duration; // Stores HC-SR04 pulse duration value
float distance; // Stores calculated distance in cm
float soundsp;  // Stores calculated speed of sound in M/S
float soundcm;  // Stores calculated speed of sound in cm/ms
int iterations = 5;
 
// Initialize DHT sensor for normal 16mhz Arduino
 
DHT dht(DHTPIN, DHTTYPE); 
 
void setup() {
  Serial.begin (9600);
  dht.begin();
}
 
void loop()
{
 
  delay(2000);  // Delay so DHT-22 sensor can stabalize
   
    hum = dht.readHumidity();  // Get Humidity value
    temp= dht.readTemperature();  // Get Temperature value
    
    // Calculate the Speed of Sound in M/S
    soundsp = 331.4 + (0.606 * temp) + (0.0124 * hum);
    
    // Convert to cm/ms
    
    soundcm = soundsp / 10000;
    
  duration = sonar.ping_median(iterations);
  
  // Calculate the distance
  distance = (duration / 2) * soundcm;
  
  // Send results to Serial Monitor
  
    Serial.print("Sound: ");
    Serial.print(soundsp);
    Serial.print(" m/s, ");
    Serial.print("Humid: ");
    Serial.print(hum);
    Serial.print(" %, Temp: ");
    Serial.print(temp);
    Serial.print(" C, ");
    Serial.print("Distance: ");
 
    if (distance >= 400 || distance <= 2) {
    Serial.print("Out of range");
    }
    else {
    Serial.print(distance);
    Serial.print(" cm");
    delay(500);
    }
  
  Serial.println(" ");
}