[Node MCU ESP8266] Monitoring DHT11 via thingspeak

Writed 24 DEC 2019

Why I am posting blog at work on Christmas Adam.

 

1. System DiagramESP8266 and DHT11 Schematic Diagram

출처: https://randomnerdtutorials.com/esp8266-dht11dht22-temperature-and-humidity-web-server-with-arduino-ide/

2. Login 

https://thingspeak.com/

IoT Analytics - ThingSpeak Internet of Things

3. Make My Channel

4. Input Text

 - There are many options with help next to them

5. Change charing setting from private to public

6. Install Library

 

7. Save as Open Example Code

 - To avoid library issues

 

8. Input your infomation

 - You can find Channel ID and Write_APIkey on API Keys tap

9. Code

#include "DHT.h"
#include "ThingSpeak.h"
#include "secrets.h"
#include <ESP8266WiFi.h>
 
#define DHTPIN 5     // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11   // DHT 11
 
DHT dht(DHTPIN, DHTTYPE);
 
char ssid[] = SECRET_SSID;   // your network SSID (name) 
char pass[] = SECRET_PASS;   // your network password
int keyIndex = 0;            // your network key Index number (needed only for WEP)
WiFiClient  client;
 
unsigned long myChannelNumber = SECRET_CH_ID;
const char * myWriteAPIKey = SECRET_WRITE_APIKEY;
 
int number = 0;
 
void setup() {
  Serial.begin(115200);  // Initialize serial
 
  WiFi.mode(WIFI_STA); 
  ThingSpeak.begin(client);  // Initialize ThingSpeak
  
  dht.begin();
}
 
void loop() {
 
  // Connect or reconnect to WiFi
  if(WiFi.status() != WL_CONNECTED){
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(SECRET_SSID);
    while(WiFi.status() != WL_CONNECTED){
      WiFi.begin(ssid, pass);  // Connect to WPA/WPA2 network. Change this line if using open or WEP network
      Serial.print(".");
      delay(5000);     
    } 
    Serial.println("\nConnected.");
  }
 
  float h = dht.readHumidity();
  float t = dht.readTemperature();
 
  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }
 
  ThingSpeak.setField(1, t);
  ThingSpeak.setField(2, h);
  
  // Write to ThingSpeak. There are up to 8 fields in a channel, allowing you to store up to 8 different
  // pieces of information in a channel.  Here, we write to field 1.
  int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
  if(x == 200){
    Serial.println("Channel update successful.");
  }
  else{
    Serial.println("Problem updating channel. HTTP error code " + String(x));
  }
 
  Serial.print(F("Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.println(F("°C "));
 
  delay(20000); // Wait 20 seconds to update the channel again
}

 

10. Result

 

Reference

- https://randomnerdtutorials.com/esp8266-dht11dht22-temperature-and-humidity-web-server-with-arduino-ide/