I build an arduino based device and connect a GSM900 module to it which can establish GPRS connection and visit website. Also I have created an account in thingspeak. I tested sending data to the field with the browser in my PC by visiting https://api.thingspeak.com/update?api_key=XXXXXXXXXXXXX&field1=0, and it does upload data and shows a number. But when I try to do the same thing with the arduino based device, after softSerial.println("GET https://api.thingspeak.com/update?api_key=XXXXXXXXXXXXX&field1=0"); It dosn't repond nor shows the number. Is there anything missing? The following is the arduino sketch and all the at command before the line above shows "ok" result. Also, is there a way to test this GSM900 module is able to get http? #include <SoftwareSerial.h> SoftwareSerial softSerial(51, 52);// void setup() { Serial.begin(9600); softSerial.begin(9600); Serial.println("Initing...please wait."); softSerial.println("AT+CPIN?"); delay(500); printLine(); softSerial.println("AT+CGATT?"); delay(500); printLine(); softSerial.println("AT+CIPSHUT"); delay(500); printLine(); softSerial.println("AT+CIPSTATUS"); delay(500); printLine(); softSerial.println("AT+CIPMUX=0"); delay(500); printLine(); softSerial.println("AT+CSTT=\"ZENNET\""); delay(500); printLine(); softSerial.println("AT+CIICR"); delay(3000); printLine(); softSerial.println("AT+CIFSR"); delay(1000); printLine(); //softSerial.println("AT+CIPSPRT=0"); // delay(1000); // printLine(); softSerial.println("AT+CIPSTART=\"TCP\",\"api.thingspeak.com\",\"80\""); //AT+CIPSTART="TCP","api.thingspeak.com","80" delay(3000); printLine(); softSerial.println("AT+CIPSEND"); delay(13000); printLine(); softSerial.println("GET https://api.thingspeak.com/update?api_key=XXXXXXXXXXXXX&field1=0"); delay(20000); printLine(); softSerial.println("\#026"); delay(3000); printLine(); softSerial.println("AT+CIPSHUT"); delay(500); printLine(); } void loop() { } void printLine() { String data; while (softSerial.available() > 0) { char c = softSerial.read(); data += c; } Serial.println(data); }