POST to server using ESP8266 module- Arduino Uno- AT+ commands

Question

I'm trying to send a set of data in Json format to a server I have set up which has a specific URL and an access token. The server requires a POST command. So my final URL is: http://myurl.com/myaccesstoken

The idea is that the Arduino UNO acquires some data from a sensor it then uses the ESP8266 to connect to wifi and send the acquired data to my server.

I do not understand why my server does not receive data

Thank you a lot in advance for your help.

I have used the following code:

---

#include "Arduino.h"
#include "ESP8266.h"
#include "SoftwareSerial.h"
#include "ArduinoJson.h"

#define ssid "mySSID"
#define pw "myPW"
#define IP "xxx.xxx.xxx.xxx"
#define URL "http://myurl.com/myaccesstoken"

int incomingByte;

void setup() {//I connect to wifi
  Serial.begin(115200);
  Serial.println("AT");
  delay(5000);
  analogReference(INTERNAL);
  if(Serial.find("OK")){
    Serial.println("AT+CWMODE=3");
    delay(1000);
    String WF=String("AT+CWJAP=\"")+ssid+"\",\""+pw+"\"";
    Serial.println(WF);
    delay(5000);}
}

void loop() {
  //JSON data creation
StaticJsonBuffer<200> jsonBuffer;
JsonObject& root = jsonBuffer.createObject();
root["flow"] = 2.54;
root["measured"] = "2017-08-14T06:16:03.418Z";
root.printTo(Serial);
delay(5000);
 // I start communication with server
 Serial.println(String("AT+CIPSTART=\"TCP\",\"") + IP + "\",80");  
 delay(5000);
 Serial.println("AT+CPSTATUS");
 // I use HTTP protocol to POST the data
    Serial.println("AT+HTTPINIT");
    delay(2000);
    Serial.println("AT+HTTPPARA=\"CID\",\"1");
    delay(2000);
    Serial.println("AT+HTTPPARA=\"URL\",\"http://myurl.com/myaccesstoken\"");
    delay(2000);
    Serial.println(String("AT+HTTPPARA=\"CONTENT\",\"application/json"));
    delay(2000);
    Serial.println("AT+HTTPDATA=\" + 81 + \",1000"); //81 is the computed length of my JSON
    delay(2000);
    Serial.println("AT+HTTPACTION=1");  
    delay(2000);    
    Serial.println("AT+HTTPREAD");
    delay(2000);
    if(Serial.available() > 0)
        {
                // read the incoming byte:
                incomingByte = Serial.read();
                // say what you got:
                Serial.print("I received: ");
                Serial.println(incomingByte);
    }
    Serial.println();
    Serial.println("AT+HTTPTERM");

    delay(5000);
  }

Answer 1

Your code doesn't work because you start by sending ESP-specific AT commands to open a socket, then you suddenly switch to SIM800-specific AT commands, and the ESP goes "WTF dude?!"

I suggest you read some tutorials on accessing web sites with the ESP8266 not with the SIM800.

Answer 2

I suggest you use computer based tools to start communication with ESP8266 module and test out sending and receiving data before you connect the module with Arduino. If you are looking for tutorials for the same then I suggest you visit this link maybe it will solve your problem or give you a direction to work on