Posts Tagged wifi

Orange Pi Zero, a sub-$20 Linux computer

Orange Pi Zero with 512MB RAM, expansion board and black case is sold for sub-$20, including postal costs, and it is so far the cheapest Linux device you can buy.

Armbian project provides a dedicated image for this board. The nightly build is quite stable, and there’s also legacy kernel which works well.

The computer is equipped with a 100/10 Ethernet NIC, and the top throughput that I could achieve was about 90Mbps.

The on-board WiFi adapter is of very poor quality: regardless of the antenna attached, it gives about 6Mbps connection speed and excessive packet loss (up to 20% lost pings). It’s useless for any practical application, and it’s easier to disable it completely.

The two USB ports on the expansion board are not enabled by default in the legacy kernel. You need to add the following line to /boot/armbianEnv.txt file, and reboot the box:

overlays=usbhost2 usbhost3

In order to disable the onboard WiFi, comment the top line, and add another line in /etc/modprobe.d/xradio_wlan.conf:

#options xradio_wlan macaddr=DC:44:6D:1F:3C:14
blacklist xradio_wlan

Then, run the following commands to update the kernel boot parameters:

depmod -ae
update-initramfs -u

The onboard USB ports are not extremely fast: with an GigE or Wifi USB adapter, the maximum speed that I could achieve was about 40Mbps. But at least you get a stable and reliable connection.

The micro-USB OTG port is used for powering the device, and the board can freeze if the power consumption on USB ports is too big. For example, an external USB drive is very likely to knock the whole thing off. A WiFi dongle can freeze at bulk traffic loads. So, it’s advisable to use an external USB hub for attaching devices.

Network Manager is installed by default by Armbian, and that allows easy plug-and-play WiFi configuration, adding new SSID and passwords from “nmcli” command-line interface.

All in all, it’s still quite a pretty device in a small enclosure. It can be used as a low-cost or throw-away network agent or VPN gateway for remote access. Also it can act as a measurement agent for all kinds of network testing, especially if you need a massive deployment and price difference is important.

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WiFi hotspot with an Ubuntu netbook

My task was to set up my Ubuntu netbook (Acer Aspire One D255E-13DQws) so that it acts as a wi-fi access point whenever I insert a USB WiFi adapter, and shares its existing connection, be it a wired RJ45 or WiFi connection on the built-in wi-fi card.

Among other use scenarios, it may be useful in hotels where only one WiFi client device is allowed in a room.

The below scenario is tested with Ubuntu 11.10, and it should work with older versions too. The TP-Link TL-WN821N is used by default, and also a Ralink3070 based adapter was working the same way.

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