Other Arduino Codes and Videos by Robojax

Arduino code and video for DHT22 Temperature and Humidity Sensor with TM1637 Display with Relay

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This is the Arduino code and video for DHT12 Temprerature and Humidity Sensor with TM1637 Display

This video shows you how to use DHT12 to measure Temperature, humidity and display it on TM1637 Display The actual sensor is AM2302 from AOSONG Chine.
  1. DHT22 without display
  2. DHT22 Library on GetHub
  3. DHT22 Manual (PDF)
  4. DHT22 Library from Robojax.com
  5. AM2302 Manufacturer Website
  6. Robojax Crash Course on Arduino: Learn Arduino in 30 Minutes (code and video)
  7. Robojax Arduino Course on Udemy
  8. Get Early Access to my videos via Patreon

 * Original code from TM1637 https://github.com/avishorp/TM1637
 * Original code and library for DHT22 https://github.com/adafruit/DHT-sensor-library
 * Watch the video for this code https://youtu.be/xD8wHXDzLkQ 
 * Other Arduino libarary and videos http://robojax.com/learn/arduino/

 * Modified for Robojax video on Jan 10, 2018
 * by Ahmad Nejrabi, in Ajax, Ontario, Canada
// ****** Start of TM1637 Display code 
#include <Arduino.h>
#include <TM1637Display.h>
// Module connection pins (Digital Pins)
#define CLK 2
#define DIO 3
// The amount of time (in milliseconds) between tests
#define TEST_DELAY   1000
TM1637Display display(CLK, DIO);
// ****** end of TM1637 Display code 

// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
// updated by Ahmad Nejrabi for Robojax.com videos.
// on Jan 10, 2018 in Ajax, Ontario, Canada

// ****** Start of DHT code 
#include "DHT.h"
#define DHTPIN 9     // what digital pin we're connected to
// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
//#define DHTTYPE DHT21   // DHT 21 (AM2301)
// ********** end of DHT22 code

#define RELAY 7 // the pin connected to relay
void setup()
  Serial.println("DHT22 Robojax Test with Display");
  pinMode(RELAY,OUTPUT);// set RELAY pin as output


void loop()
  delay(TEST_DELAY);// wait
  // **** TM1637 code start
  display.setBrightness(0x0f);// set brightness
  uint8_t data[] = { 0x0, 0x0, 0x0, 0x0 };// clear display values
  display.setSegments(data);//clear display
  // **** TM1637 code end

  // Robojax.com test video

  int temp = round(getTemp("c"));
  display.showNumberDec(temp, false, 3,1);
 if(temp >50 )
  digitalWrite(RELAY, LOW);
  digitalWrite(RELAY, HIGH);

}// loop end

 * getTemp(String req)
 * returns the temprature related parameters
 * req is string request
 * getTemp("c") will return temprature in Celsius
 * getTemp("hic") will return heat index in Celsius
 * getTemp("f") will return temprature in Fahrenheit
 * getTemp("hif") will return temprature in Fahrenheit
  * getTemp("h") will return humidity
float getTemp(String req)

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println("Failed to read from DHT sensor!");
  // Compute heat index in Kelvin 
  float k = t + 273.15;
  if(req =="c"){
    return t;//return Cilsus
  }else if(req =="f"){
    return f;// return Fahrenheit
  }else if(req =="h"){
    return h;// return humidity
  }else if(req =="hif"){
    return hif;// return heat index in Fahrenheit
  }else if(req =="hic"){
    return hic;// return heat index in Cilsus
  }else if(req =="k"){
    return k;// return temprature in Kelvin
    return 0.000;// if no reqest found, retun 0.000


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