Adhoc network on Raspberry Pi 4

Pi Image
#1

Hello,

I’m running the ubiquityrobotics raspberry pi 4 2019-06-19-ubiquity-xenial-lxde image on my UAV companion computer. ROS is working, including multimaster and connecting wired internet works well. I have 3 of these PIs set up on an ad-hoc networks with the following configuration in the /etc/network/interfaces file:

# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d

# The loopback network interface
auto lo
iface lo inet loopback

#auto eth0
#iface eth0 inet dhcp

auto wlan0
iface wlan0 inet static
    address 10.42.0.3
    netmask 255.255.255.0
    gateway 10.42.0.1
    wireless-channel 1
    wireless-essid dragonflyadhoc
    wireless-mode ad-hoc
    wireless-key s:xxxx

This works from boot, but often the connection becomes unavailable after a couple minutes. Looking at the syslog, I can’t see any related issues that come up.

Is there a different or proper way to setup an ad-hoc network with this image?

Thanks.

#2

I don’t know of anyone who has tried ad-hoc mode on our image, sorry. We generally use AP mode instead.

See if there is something in the dmesg log or maybe in journalctl -b.

#3

Hmm, nothing notable in dmesg or journalctl -b either. What’s strange is the adhoc network behaves normally from boot for a time period (ping, ssh, etc works) then just shuts off silently.

I do see this error from pifi during boot, but during that time period the adhoc network is functional:

Mar  2 17:08:13 ubiquityrobot pifi_startup[650]: Initializing AP Mode
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]: Traceback (most recent call last):
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:   File "/usr/bin/pifi_startup", line 9, in <module>
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:     load_entry_point('pifi==0.6.0', 'console_scripts', 'pifi_startup')()
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:   File "/usr/lib/python3/dist-packages/pifi/startup.py", line 123, in main
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:     start_ap_mode(pifi_conf_settings, ApModeDevice, ClientModeDevice)
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:   File "/usr/lib/python3/dist-packages/pifi/startup.py", line 70, in start_ap_mode
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:     NetworkManager.NetworkManager.AddAndActivateConnection(settings, ApModeDevice, "/")
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:   File "<string>", line 6, in AddAndActivateConnection
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:   File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 145, in __call__
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:     **keywords)
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:   File "/usr/lib/python3/dist-packages/dbus/connection.py", line 651, in call_blocking
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]:     message, timeout)
Mar  2 17:08:13 ubiquityrobot pifi_startup[650]: dbus.exceptions.DBusException: org.freedesktop.NetworkManager.UnknownConnection: Connection 'Pifi AP Mode' is not available on the device wlan0 at this time.
Mar  2 17:08:13 ubiquityrobot systemd[1]: pifi.service: Main process exited, code=exited, status=1/FAILURE
Mar  2 17:08:13 ubiquityrobot systemd[1]: pifi.service: Unit entered failed state.
Mar  2 17:08:13 ubiquityrobot systemd[1]: pifi.service: Failed with result 'exit-code'.
#4

Maybe pifi/NetworkManager is doing something screwy in the background that is causing your network to fail.

Try disabling pifi with sudo systemctl disable pifi

Rohan

#5

Although it removes the error from the log, the problem with the adhoc connection is the same. I did notice that cycling a sudo ifdown wlan0 and sudo ifup wlan0 restores the network. Is there another log associated with the network of if* that may give some more clues?

#6

You could try checking /var/log/syslog or dmesg, but after that I am unsure of anywhere else to check.

Rohan

#7

Playing with some of the configurations, it seems I just needed to change the channel that I was running on. Thanks for your help @rohbotics

1 Like
#8

Glad you got it working!
Good luck with your project.

Rohan