I have been interested in the Ubiquiti Ministation Wifi AP for a while now and recently purchased one. It is marketed as "The World's Smallest 802.11 AP Development Platform with a full Linux SDK available". I have had a chance to play with it for a few weeks now and must say that the hardware and the bundled router operating system called "Air OS" is excellent. The web based user interface is easy to use and works well. All of the settings a normal user would want are available and quick to setup. There is even a dialog and special mode that helps with antenna pointing that has onscreen colored signal strength bars and configurable LEDs on the AP board that give you an idea on the signal strength of the link at a glance.

Ubiquity also provides a Linux SDK and GCC based Toolchain that lets you compile custom builds of the firmware to suit your needs. You can download the Ubiquiti SDK here. I used Ubuntu in a VMWare virtual machine to compile my own custom modified version of the version 3.5 firmware.

Based upon suggestions on the Ubiquiti Forums I edited the inittab file located in the SDK.UBNT.v3.5.4999/rootfs/ls2/usr/etc folder. I commented out the 4th line to read: #ttys0::askfirst:/sbin/getty -L ttyS0 9600 vt100
This disconnects the serial console from the serial port at start-up and allows you to use the hardware serial port as a network serial port using NC.

The commands I used to build the firmware for the Ministation were:

cd SDK.UBNT.v3.5.4499
sudo bash
make clean
make xs2

The compiled firmware is located in the SDK.UBNT.v3.5.4999/rootfs/XS2.ar2316.v3.5.latest folder with a name similar to XS2.ar2316.v3.5.SDK.100611.1136.bin. The last part after the .SDK. and before the file extension .bin changes between builds.

Use the web admin interface to flash the firmware. With the default setup for the Ubiquiti firmware the username is UBNT and the password is UBNT. As always, it is a good idea to read about recovery procedures before upgrading your firmware should you have a power interruption during flashing.

To launch an SSH session with the AP load up your terminal and type:

ssh 192.168.1.25 -l ubnt

The pinout for the Ministation board according to the website linuxfreak is:

Pin 1: + 3.3VDC
Pin 2: + 3.3VDC
Pin 3: Serial RX
Pin 5: GND
Pin 7: Serial TX
Pin 9: GND
Pin 10: GND

You will need a 3.3 Volt TTL compatible serial port interface such as a FTDI usb to serial adapter to communicate with the serial port.

If anyone has success creating the proper makefile to compile ser2net for the Ubiquiti Ministation I would be very interested in hearing about it!

One Response to “Worlds Smallest Wifi AP? Yes it is!”

1. dendy says:

   September 26, 2010 at 8:43 am

   interesting post!