no output in ar.drone control program

Question

     #include <stdlib.h> // for exit() //
     #include <netdb.h>
     #include <stdio.h>
     #include <string.h>   // memset() //

     #define DRONE_COMMAND_PORT 5556
     #define MAX_MSG 2048

     int main(int argc, char *argv[]) {

          // declare variables
          int    sd, rc, flags, nd;
          char   command[MAX_MSG];  
          struct sockaddr_in clientAddr;
          struct sockaddr_in droneAddr;
          struct hostent     *h;
          struct timespec    wait_command;

          int seq=0;
          char msg[MAX_MSG];

          // initialize variables
          flags = 0;
          wait_command.tv_sec  = 0;
          wait_command.tv_nsec = 5000000;

          // check command line args //
         if(argc<2) {
         printf("usage : %s <server name/IP>\n", argv[0]);
         exit(EXIT_FAILURE);
         }

         // get server IP address (no check if input is IP address or DNS name)
         h = gethostbyname(argv[1]);
         if(h==NULL) {
         printf("%s: unknown host '%s' \n", argv[0], argv[1]);
         exit(EXIT_FAILURE);
         }

         // create structure for ardrone address & port
         droneAddr.sin_family = h->h_addrtype;
         droneAddr.sin_port   = htons(DRONE_COMMAND_PORT);
         memcpy((char *) &droneAddr.sin_addr.s_addr, h->h_addr_list[0], h->h_length);
         // create structure for this client
         clientAddr.sin_family = AF_INET;
         clientAddr.sin_addr.s_addr = htonl(INADDR_ANY);
         clientAddr.sin_port = htons(0);

         // socket creation
         sd = socket(AF_INET,SOCK_DGRAM,0);
         if(sd<0) {
         printf("%s: cannot open socket \n",argv[0]);
         exit(EXIT_FAILURE);
         }
         // bind client's the port and address
         rc = bind(sd, (struct sockaddr *) &clientAddr, sizeof(clientAddr));
         if(rc<0) {
         printf("%s: cannot bind port\n", argv[0]);
         exit(EXIT_FAILURE);
         }
        // send commands
        char cmd[MAX_MSG],cmd2[MAX_MSG],cmd3[MAX_MSG],cmd4[MAX_MSG];
         int i;
        snprintf(cmd,MAX_MSG,"AT*CONFIG= %u,\"general:navdata_demo\",\"TRUE\"",seq);
        printf("%s: %s\n",argv[0],cmd);
        sendto(sd, cmd, MAX_MSG , flags, (struct sockaddr *) &droneAddr, sizeof(droneAddr));
        seq++;
        snprintf(cmd2,MAX_MSG,"AT*FTRIM=%u",seq);
        printf("%s: %s\n",argv[0],cmd2);
        sendto(sd, cmd2, MAX_MSG , flags, (struct sockaddr *) &droneAddr, sizeof(droneAddr));
        seq++;
        snprintf(cmd3,MAX_MSG,"AT*PMODE= %u,2",seq);
        printf("%s: %s\n",argv[0],cmd3);
        sendto(sd, cmd3, MAX_MSG , flags, (struct sockaddr *) &droneAddr, sizeof(droneAddr));
        seq++;
        char cmd1[MAX_MSG];
        printf("%s: sending commands to  %d\n", argv[0], inet_ntoa(*(struct in_addr *)h->h_addr_list[0]));
        for(i=0;i<10;i++)
        { 
    cmd1[strlen(cmd1)-1] = 0x0d;  // change last character from new line to carriage return

        snprintf(cmd1,MAX_MSG,"AT*REF=%u,290718208",seq);
        printf("%s: %s\n",argv[0],cmd1);
        snprintf(cmd1,MAX_MSG,"AT*REF=%u,290718208",seq+1);
        printf("%s: %s\n",argv[0],cmd1);
        snprintf(cmd1,MAX_MSG,"AT*REF=%u,290718208",seq+2);
        printf("%s: %s\n",argv[0],cmd1);
        snprintf(cmd1,MAX_MSG,"AT*REF=%u,290718208",seq+3);
        printf("%s: %s\n",argv[0],cmd1);
        snprintf(cmd4,MAX_MSG,"AT*COMWDG=%u",seq+4);
        printf("%s :%s\n",argv[0],cmd4);

        rc = sendto(sd, cmd1, MAX_MSG , flags,  (struct sockaddr *) &droneAddr, sizeof(droneAddr));
        if(rc<0) {
        printf("%s: can not send data\n",argv[0]);
        close(sd);
        exit(EXIT_FAILURE);
        }
        seq=seq+5;
        nanosleep(&wait_command , NULL);
        }
        return 1;
        }

Hi, This is my program to take-off ar.drone. I am not getting any errors when i compile it. But the drone is not taking-off. The at commands in printf statements are getting printed. there is no error in that also. Can anyone tell me if there is any error in my program or why my program is not working?

thanks in advance.

with regards, shiksha

Answer 1

I always send the following sequence:

"AT*CONFIG=1,\"general:navdata_demo\",\"TRUE\"\r"

"AT*CTRL=0\r"

Then whatever you want starting with a sequence number of 1.

I think you are missing the AT*CTRL=0/r

Answer 2

Try to use

connect()

instead of bind the port.