Building a custom wireless router

Michael L Torrie torriem at gmail.com
Thu May 22 00:48:59 MDT 2008


Brad Midgley wrote:

> I have a few little linux computers with arm cpus that can do usb host, 
> so I thought I would set up an access point that way for custom stuff, 
> similar to your idea except these are slower. I figured it would uplink 
> through bluetooth to a phone or something.
> 
> I found there are no decent drivers for usb wifi adapters. Nothing I 
> could find can do master mode in particular.
> 
> I'm also curious to see what you come up with.

Here's the word so far.  The easy stuff is all done.

I bought a little Alix board that's an AMD Geode processor (400 MHz)
with 256 MB of ram, although 128 would do.  I bought an Atheros MiniPCI
card to go with it for the wireless part.  Stuck this in a little case
and now I have a 6"x6"x2" router with at present a single antenna
sticking out the back.  Will do dual later.  Total price $230.  With the
128MB ram version, I think it could be done for right around $200 if you
shopped around a bit for the other parts like the case (prices vary
dramatically) and the antennas and pigtails.

That latest trunk of OpenWRT Kamikaze happens to support the Alix as a
profile (mainly just includes a couple of needed kernel drivers
modules).  So I downloaded the source, filled the package tree, and
configured the thing.  Made sure the Atheros wireless stuff was being
built, included WebIf2 (X-wrt.org), and built an image, which I wrote to
a compact flash card.  So far my image is 48 MB, but I think I'll
eventually create a 64 MB or 128 MB one, depending on the blacklists
that are desired.

Anyway, I got the router up and running.  Used a serial console to get
it all working initially.  As configured by default, the ethernet ports
weren't set up at all really.  OpenWRT emulates vlans, so I created a
vlan (these are really just bridging groups on this machine, not vlans
like on the linksys) call LAN and put ports 2  and 3 in that.  Made port
1 be the wan port.  Then I got the atheros wireless working, and stuck
it in the bridge lan, which is the default behavior on most routers.  I
edited config files to do this, but found out later that the web
interface can do all of that.

So now it's to the point where it's a full wireless router with all the
functionality of a linksys.  Today I build packages (all part of the
OpenWRT build system) for tinyproxy and dansguardian.  My next step is
to set it up manually and then test it.  I am confident it will run fine.

After that, it's time to build or adapt a web client for dansguardian.

If anyone wants, I'll be happy to send them my openwrt build config
file, and default uci config files for network and wireless, or a
prebuilt image.

I'm very happy with this Alix deal so far and doubt I will ever mess
about with Linksys or Asus or whatever routers again.  It's so nice to
have all th storage I want and lots of power to burn, only for about
twice the price!  I have enough space to put on python and get some real
scripting done in a hurry.  The most important thing, of course, is a
full version vim.

In the next month, watch for an Asus 500G Premium being sold cheap
(running Kamikaze itself, of course).



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