mavproxy sends data '0'

[junhyuk9976]

The first time I used MavProxy, the behavior was normal.
At some point, MavProxy started inserting data zero.
help please.

[peterbarker]

How did you provoke that alt: output?

[junhyuk9976]

How did you provoke that alt: output?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <fcntl.h> // Contains file controls like O_RDWR
#include <errno.h> // Error integer and strerror() function
#include <termios.h> // Contains POSIX terminal control definitions
#include <common/mavlink.h>
#include <ardupilotmega/ardupilotmega.h>

#define ARMED 128 //ARM FlAG Value
#define BUFFER_LENGTH 1024 // minimum buffer size that can be used with qnx (I don't know why)

int main()
{
//--------------------------------------------UDP SETTING--------------------------------------------------------------
char target_ip[100];
int sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
struct sockaddr_in UDP_Comm;
uint8_t buf[BUFFER_LENGTH];
ssize_t recsize;
socklen_t fromlen = sizeof(UDP_Comm);
unsigned int temp = 0;

    //------the target ip---------------------------------------------------------------
    strcpy(target_ip, "127.0.0.1");

    memset(&UDP_Comm, 0, sizeof(UDP_Comm));
    UDP_Comm.sin_family = AF_INET;
    UDP_Comm.sin_addr.s_addr = inet_addr(target_ip);
    UDP_Comm.sin_port = htons(14551);

    /* Bind the socket to port - necessary to receive packets from qgroundcontrol */
    if (-1 == bind(sock,(struct sockaddr *)&UDP_Comm, sizeof(struct sockaddr)))
{
            perror("error bind failed");
            close(sock);
            exit(EXIT_FAILURE);
}

//--------------------------------------------UDP SETTING END----------------------------------------------------------

    int i = 0;

    int armed_state; //-----------------------------------------------------------------
    int altitude;

    // Something received - print out all bytes and parse packet
    mavlink_message_t msg;
    mavlink_status_t status;
    mavlink_heartbeat_t hb;
    mavlink_global_position_int_t position;
    mavlink_mount_control_t gim_cont;

    for (;;)
    {

//--------------------------------------------READ MAVLINK MSG---------------------------------------------------------
memset(buf, 0, BUFFER_LENGTH);
recsize = recvfrom(sock, (void *)buf, BUFFER_LENGTH, 0, (struct sockaddr *)&UDP_Comm, &fromlen);
if (recsize > 0)
{
for (i = 0; i < recsize; ++i)
{
temp = buf[i];
if (mavlink_parse_char(MAVLINK_COMM_0, buf[i], &msg, &status))
{
switch (msg.msgid)
{
case MAVLINK_MSG_ID_HEARTBEAT:
{
mavlink_msg_heartbeat_decode(&msg, &hb);
armed_state = hb.base_mode & MAV_MODE_FLAG_SAFETY_ARMED;
//printf("ARM State: %d\n", armed_state);

                                            }
                                            case MAVLINK_MSG_ID_GLOBAL_POSITION_INT:
                                            {
                                                    mavlink_msg_global_position_int_decode(&msg, &position);
                                                    altitude = position.relative_alt;
                                                    //printf("alt: %d\n", position.relative_alt);
                                            }
                                            case MAVLINK_MSG_ID_MOUNT_CONTROL:
                                            {
                                                    mavlink_msg_mount_control_decode(&msg, &gim_cont);
                                                    printf("Gimbal Pitch: %d\n", gim_cont.input_a);
                                            }
                                    }
                            }
                    }
            }

//--------------------------------------------READ MAVLINK MSG END-----------------------------------------------------

            if(armed_state==ARMED)
            {
                //printf("Light On!!!\n");
            }
            else if(armed_state!=ARMED)
            {
                //printf("Light OFF!!!\n");
            }
            sleep(0.01); // Sleep one second
    }

}

here is the cord

[peterbarker]

On Mon, 22 Jun 2020, junhyuk9976 wrote: How did you provoke that alt: output? case MAVLINK_MSG_ID_GLOBAL_POSITION_INT: { mavlink_msg_global_position_int_decode(&msg, &position); altitude = position.relative_alt; //printf("alt: %d\n", position.relative_alt); here the cord

Thanks. Do you think MAVProxy is emitting GLOBAL_POSITION_INT messages?

[junhyuk9976]

On Mon, 22 Jun 2020, junhyuk9976 wrote: How did you provoke that alt: output? case MAVLINK_MSG_ID_GLOBAL_POSITION_INT: { mavlink_msg_global_position_int_decode(&msg, &position); altitude = position.relative_alt; //printf("alt: %d\n", position.relative_alt); here the cord
Thanks. Do you think MAVProxy is emitting GLOBAL_POSITION_INT messages?

Yes I think so.
SiTL with gazebo had the same symptoms.
Why is this?

[junhyuk9976]

On Mon, 22 Jun 2020, junhyuk9976 wrote: How did you provoke that alt: output? case MAVLINK_MSG_ID_GLOBAL_POSITION_INT: { mavlink_msg_global_position_int_decode(&msg, &position); altitude = position.relative_alt; //printf("alt: %d\n", position.relative_alt); here the cord
Thanks. Do you think MAVProxy is emitting GLOBAL_POSITION_INT messages?

Yes I think so.
SiTL with gazebo had the same symptoms.
Why is this?

Sorry. This was caused by the absence of a break statement in the switch-case statement.