# VOXL Connection to MAVLINK server failed using pymavlink

Source: https://forum.modalai.com/topic/4015/voxl-connection-to-mavlink-server-failed-using-pymavlink
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2024-12-12 17:28:01 UTC by svempati
Replies: 5 · Views: 1365

## svempati · 2024-12-12 17:28:01 UTC

Hello, I am trying to read mavlink messages like the pressure and altitude from the VOXL 2 sensors using pymavlink. I wanted to make sure that the udpin to the mavlink connection is correct? 

I am having trouble connecting to the mavlink server. I set the port number to 14557 based on the first diagram in this page: (https://docs.modalai.com/mavlink/).
When I use `localhost` as the port, . When I use `localhost`, I get an error that says `OSError: [Errno 98] Address already in use`, and when I use the IP address `192.168.8.10` it gives an error that says `OSError: [Errno 99] Cannot assign requested address`. 

If that is not the correct IP address, how can I find the IP address for my specific VOXL? It is worth noting that my VOXL isn't connected to the internet, but is physically connected to the flight controller by wire.

Thanks for your help!

```
# MAVLINK Common Message Set: https://mavlink.io/en/messages/common.html
from pymavlink import mavutil

the_connection = mavutil.mavlink_connection('udpin:192.168.8.10:14557')

the_connection.wait_heartbeat()
print("Heartbeat from system (system %u component %u)" % (the_connection.target_system, the_connection.target_component))

while True:
    try:
        # local xyz position
        msg_pos = the_connection.recv_match(type='LOCAL_POSITION_NED', blocking=True)
        print(msg_pos.x, msg_pos.y, msg_pos.z)

        # altitude
        msg_altitude = the_connection.recv_match(type='ALTITUDE', blocking=True)
        print(msg_altitude.altitude_local, msg_altitude.altitude_relative)

        # pressure
        msg_pressure = the_connection.recv_match(type='SCALED_PRESSURE', blocking=True)
        print(msg_pressure.press_abs)

    except KeyboardInterrupt:
        print('Terminating mavlink...')
        break
```

## Reply by tom (ModalAI staff) · 2024-12-13 20:14:52 UTC

@svempati You can run `ifconfig` to view the IP addresses for your various network interfaces on voxl2, if you're using wifi then you'll want to look at `wlan0`

## Reply by svempati · 2024-12-17 18:21:16 UTC (in reply to tom)

@tom I ran `ifconfig` on voxl2, but I haven't found anything on `wlan0`. This is the output I get after running that command:

```
bond0: flags=5123<UP,BROADCAST,MASTER,MULTICAST>  mtu 1500
        ether fe:ca:d2:74:91:69  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

dummy0: flags=195<UP,BROADCAST,RUNNING,NOARP>  mtu 1500
        inet6 fe80::e2a:ce35:6c11:d803  prefixlen 64  scopeid 0x20<link>
        ether de:92:20:5e:07:c9  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 25  bytes 7462 (7.4 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 368130  bytes 35420354 (35.4 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 368130  bytes 35420354 (35.4 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
```

would any of these help with finding the voxl's ip address?

## Reply by tom (ModalAI staff) · 2024-12-17 19:29:18 UTC (in reply to svempati)

@svempati Do you have a wifi dongle connected to VOXL2?

## Reply by svempati · 2024-12-18 18:28:45 UTC (in reply to tom)

@tom No I don't have a wifi dongle connected.

## Reply by tom (ModalAI staff) · 2024-12-18 19:17:08 UTC (in reply to svempati)

@svempati Are you trying to access the mavlink data from VOXL 2 itself or from an offboard computer / ground station?