Go Down

Topic: DFRobot SIM808 HTTP connection problem in loop (Read 71 times) previous topic - next topic


I have following code which trying to make HTTP Connection with server using DFRobot library (SIM808_TCPConnection) for SIM8080 Module.

My purpose is to reading and writing data using HTTP connection then when Iam trying to put this code inside loop the connection HANG and give me Nwtwork not available and GPRS connection fall down

How I can keep connection available every time inside the loop to update the server every n seconds ?

Code: [Select]
### Connect TCP and send GET request.
1. This example is used to test DFRobot_SIM808 GPS/GPRS/GSM Shield's connect TCP and send GET request.
2. Open the SIM808_TCPConnection example or copy these code to your project
3. Download and dial the function switch to Arduino
4. Open serial helper
5. Waiting for a few minutes, until serial has sent "Connect mbed.org success"
6. Serial will send "Hello world!"
create on 2016/09/23, version: 1.0
by jason
#include <DFRobot_sim808.h>
#include <SoftwareSerial.h>

//#define PIN_TX    10
//#define PIN_RX    11
//SoftwareSerial mySerial(PIN_TX,PIN_RX);
//DFRobot_SIM808 sim808(&mySerial);//Connect RX,TX,PWR,

//make sure that the baud rate of SIM900 is 9600!
//you can use the AT Command(AT+IPR=9600) to set it through SerialDebug

DFRobot_SIM808 sim808(&Serial);

char http_cmd[] = "GET /media/uploads/mbed_official/hello.txt HTTP/1.0\r\n\r\n";
char buffer[512];

void setup(){
  //******** Initialize sim808 module *************
  while(!sim808.init()) {
      Serial.print("Sim808 init error\r\n");

void loop(){

//*********** Attempt DHCP *******************
  while(!sim808.join(F("cmnet"))) {
      Serial.println("Sim808 join network error");

  //************ Successful DHCP ****************
  Serial.print("IP Address is ");

  //*********** Establish a TCP connection ************
  if(!sim808.connect(TCP,"mbed.org", 80)) {
      Serial.println("Connect error");
      Serial.println("Connect mbed.org success");

  //*********** Send a GET request *****************
  Serial.println("waiting to fetch...");
  sim808.send(http_cmd, sizeof(http_cmd)-1);
  while (true) {
      int ret = sim808.recv(buffer, sizeof(buffer)-1);
      if (ret <= 0){
          Serial.println("fetch over...");
      buffer[ret] = '\0';
      Serial.print("Recv: ");
      Serial.print(" bytes: ");

  //************* Close TCP or UDP connections **********

  //*** Disconnect wireless connection, Close Moving Scene *******


Go Up