esp8266 issue when trying to connect to the internet - http

Question

I use this code and try to connect my esp8266 so it will upload temperature to thingspeak.com
#include <SoftwareSerial.h>
#include <stdlib.h>
// LED
int ledPin = 13;
// LM35 analog input
int lm35Pin = A0;
// replace with your channel's thingspeak API key
String apiKey = "xxxxxx";
// connect 10 to TX of Serial USB
// connect 11 to RX of serial USB
SoftwareSerial ser(10, 11); // RX, TX
void setup() {
pinMode(ledPin, OUTPUT);
Serial.begin(115200);
ser.begin(115200);
ser.println("AT+RST");
}
void loop() {
digitalWrite(ledPin, HIGH);
delay(200);
digitalWrite(ledPin, LOW);
int val = 0;
for(int i = 0; i < 10; i++) {
val += analogRead(lm35Pin);
delay(500);
}
float temp = val*50.0f/1023.0f;
char buf[16];
String strTemp = dtostrf(temp, 4, 1, buf);
Serial.println(strTemp);
String cmd = "AT+CIPSTART=\"TCP\",\"";
cmd += "184.106.153.149"; // api.thingspeak.com
cmd += "\",80";
ser.println(cmd);
if(ser.find("Error")){
Serial.println("AT+CIPSTART error");
return;
}
String getStr = "GET /update?api_key=";
getStr += apiKey;
getStr +="&field1=";
getStr += String(strTemp);
getStr += "\r\n\r\n";
cmd = "AT+CIPSEND=";
cmd += String(getStr.length());
ser.println(cmd);
if(ser.find(">")){
ser.print(getStr);
}
else{
ser.println("AT+CIPCLOSE");
Serial.println("AT+CIPCLOSE");
}
delay(16000);
}
When running the code i get this in the serial monitor:
21
AT+CIPCLOSE
21
AT+CIPCLOSE
21
AT+CIPCLOSE
21 will be the temperature

Answer 1

On the firmware version that I use the return for a failure on AT+CIPSTART is "ERROR" and not "Error" so that might be the reason why you never see that the connection has failed. Try the above via a serial Terminal connected to the ESP8266 and check what the returns are.
Also, you need to learn to stay away from Strings in AVR programming. Rather use char arrays.