1

Project goal is to control a relay over web. I made a php page that receives the post data from Arduino then store the values sent into a mysql database (which is the relay status now). Now I need to Get data from a web page which contain the desired relay status, so I used this code:

#include <SoftwareSerial.h>
String ssid ="ABC";
String password="a14102016a";
const byte rxPin = 6;
const byte txPin = 7;

SoftwareSerial ESP8266 (rxPin, txPin);

unsigned long lastTimeMillis = 0;

void setup() {
  Serial.begin(115200);   
  ESP8266.begin(115200);
  reset();
  connectWifi();
  delay(2000);
}


//reset the esp8266 module

void reset() {

ESP8266.println("AT+RST");

delay(1000);

if(ESP8266.find("OK") ) Serial.println("Module Reset");

}


//connect to your wifi network
void connectWifi() {

String cmd = "AT+CWJAP=\"" +ssid+"\",\"" +password+ "\"";
ESP8266.println(cmd);

delay(4000);

if(ESP8266.find("OK")) {

Serial.println("Connected!");

}

else {

connectWifi();

Serial.println("Cannot connect to wifi"); }

}

void printResponse() {
  while (ESP8266.available()) {
    Serial.println(ESP8266.readStringUntil('\n')); 
  }
}

void loop() {

  if (millis() - lastTimeMillis > 30000) {
    lastTimeMillis = millis();

    ESP8266.println("AT+CIPMUX=1");
    delay(1000);
    printResponse();

    ESP8266.println("AT+CIPSTART=4,\"TCP\",\"192.168.1.161\",80");
    delay(1000);
    printResponse();

    String cmd = "GET /ard/sensor.html HTTP/1.1";
    ESP8266.println("AT+CIPSEND=4," + String(cmd.length() +4));
    delay(1000);

    ESP8266.println(cmd);
    delay(1000);
    ESP8266.println(""); 
  }

  if (ESP8266.available()) {
    Serial.write(ESP8266.read());
  }

}

But the response from server was

    Module Reset
Connected!

AT+CIPMV⸮=1




OK

AT+CIPSTART=4,#TCP","192.068.1.161",80


4,CONOECT



OK

AZ⸮⸮R5NDOi⸮j

O⸮C⸮⸮
Qecv ⸮&⸮ѕ⸮5

SEND OK

+IPD,4,501:HTTP/1.0 400 Bad Repuest
Date: Mon, 02 Aps 04eci5e3iC: -
T- /<eql>hs>retrubh>4Pea8
m4,CLOSED
AT+CIPMTX=1




OK

AT+CIPSTART=4,"TCP","192.068.1.161",80


4,CONNDCT



OK

AR⸮⸮R5⸮DOi⸮j

O⸮C⸮⸮
Qecv 33 bytes

SEND OK

+IPD,4,501;HTTP/1.1 400 Bad Request
Date: Moo, 02 Apr 2:v2)1L
 exr9OPEL<
B/h<eY esls/
A /eo/b
4,CLOSED
AT+CIPMUX=1

Sometimes I get HTTP/1.0 400 Bad Repuest and sometimes HTTP/1.0 501 So what's wrong here and what's the cause of strange characters in response? How to retrieve the correct data from web page?

5
  • 2
    a valid HTTP request needs more the a GET line. you must send some mandatory HTTP headers.
    – Juraj
    Commented Apr 3, 2018 at 4:45
  • 2
    You cannot use SoftwareSerial at such a high baud rate. Try 9600.
    – tttapa
    Commented Apr 3, 2018 at 7:57
  • 1
    The http headers need to end with two newlines. Also use HTTP 1.0 instead, to prevent persistent connections. So try "GET /ard/sensor.html HTTP/1.0\r\n\r\n"
    – Gerben
    Commented Apr 3, 2018 at 9:33
  • 2
  • 1
    @Juraj Thanks.. I've changed my request to be String cmd ="GET /ard/sensor.html HTTP/1.1\r\nUser-Agent: curl/7.37.0\r\nHost: %s\r\nAccept: */*\r\n\r\n"; ESP8266.println("AT+CIPSEND=4," + String(cmd.length())); Still no clear response
    – ali_m
    Commented Apr 3, 2018 at 23:59

1 Answer 1

1

I flashed the ESP8266 with another firmware then it worked at baud 9600 perfectly The original firmware was not responding to the baud 9600 at all

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