ESP8266 Community Forum

- Mon Dec 11, 2017 2:20 pm #72455 Hi...

Objective: I want to control a relay connected to ESP8266 via Cloud / Online. I have a DHT11 Temp-Humidity Sensor connected to Arduino. Arduino and ESP8266 are connected over Serial.

I am able to pass on Temp / Humidity data from Arduino to ESP 8266 , which passes on data to Thingspeak.com Channel successfully. I want, however to control a relay connected to ESP8266 (and not on the Arduino) from Thingspeak website. I am not sure, if ESP8266 can work in a mixed mode (passing Serial Data to Thingspeak and at same time be listening to Incoming commands from Thingspeak. Below is the code what is setup in Arduino. ESP 8266 is basically having default AI Thinkers AT firmware.

Any help or thoughts?

Many Thanks in advise.

Code: Select all#include <SoftwareSerial.h>
SoftwareSerial espSerial =  SoftwareSerial(2,3);      // arduino RX pin=2  arduino TX pin=3    connect the arduino RX pin to esp8266 module TX pin   -  connect the arduino TX pin to esp8266 module RX pin



#include <DHT.h>        //Attention: For new  DHT11 version  library you will need the Adafruit_Sensor library
                        //Download from here: https://github.com/adafruit/Adafruit_Sensor



//Attention: For new  DHT11 version  libraries you will need the Adafruit_Sensor library
//Download from here:https://github.com/adafruit/Adafruit_Sensor
//and install to Arduino software

#define DHTPIN 5                // Connect the signal pin of DHT11 sensor to digital pin 5
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);


String apiKey = "DK59X5DLS04TVFG5";     // replace with your channel's thingspeak WRITE API key

String ssid="WIFI NAME";    // Wifi network SSID
String password ="WIFI PASSWORD";  // Wifi network password

boolean DEBUG=true;

//======================================================================== showResponce
void showResponse(int waitTime){
    long t=millis();
    char c;
    while (t+waitTime>millis()){
      if (espSerial.available()){
        c=espSerial.read();
        if (DEBUG) Serial.print(c);
      }
    }
                   
}

//========================================================================
boolean thingSpeakWrite(float value1, float value2){
  String cmd = "AT+CIPSTART=\"TCP\",\"";                  // TCP connection
  cmd += "184.106.153.149";                               // api.thingspeak.com
  cmd += "\",80";
  espSerial.println(cmd);
  if (DEBUG) Serial.println(cmd);
  if(espSerial.find("Error")){
    if (DEBUG) Serial.println("AT+CIPSTART error");
    return false;
  }
 
 
  String getStr = "GET /update?api_key=";   // prepare GET string
  getStr += apiKey;
 
  getStr +="&field1=";
  getStr += String(value1);
  getStr +="&field2=";
  getStr += String(value2);
  // getStr +="&field3=";
  // getStr += String(value3);
  // ...
  getStr += "\r\n\r\n";

  // send data length
  cmd = "AT+CIPSEND=";
  cmd += String(getStr.length());
  espSerial.println(cmd);
  if (DEBUG)  Serial.println(cmd);
 
  delay(100);
  if(espSerial.find(">")){
    espSerial.print(getStr);
    if (DEBUG)  Serial.print(getStr);
  }
  else{
    espSerial.println("AT+CIPCLOSE");
    // alert user
    if (DEBUG)   Serial.println("AT+CIPCLOSE");
    return false;
  }
  return true;
}
//================================================================================ setup
void setup() {               
  DEBUG=true;           // enable debug serial
  Serial.begin(9600);
 
  dht.begin();          // Start DHT sensor
 
  espSerial.begin(115200);  // enable software serial
                          // Your esp8266 module's speed is probably at 115200.
                          // For this reason the first time set the speed to 115200 or to your esp8266 configured speed
                          // and upload. Then change to 9600 and upload again
 
  //espSerial.println("AT+RST");         // Enable this line to reset the module;
  //showResponse(1000);

  //espSerial.println("AT+UART_CUR=9600,8,1,0,0");    // Enable this line to set esp8266 serial speed to 9600 bps
  //showResponse(1000);
 
 

  espSerial.println("AT+CWMODE=1");   // set esp8266 as client
  showResponse(1000);

  espSerial.println("AT+CWJAP=\""+ssid+"\",\""+password+"\"");  // set your home router SSID and password
  showResponse(5000);

   if (DEBUG)  Serial.println("Setup completed");
}


// ====================================================================== loop
void loop() {

  // Read sensor values
   float t = dht.readTemperature();
   float h = dht.readHumidity();
        if (isnan(t) || isnan(h)) {
        if (DEBUG) Serial.println("Failed to read from DHT");
      }
      else {
          if (DEBUG)  Serial.println("Temp="+String(t)+" *C");
          if (DEBUG) Serial.println("Humidity="+String(h)+" %");
           thingSpeakWrite(t,h);                                      // Write values to thingspeak
      }
 
   
  // thingspeak needs 15 sec delay between updates,     
  delay(20000); 
}