StompBox

Starting with Soekris

After driving over the hill and picking up the net4521 I opened it up to have a look around. The Verizon 5220 card fit right in, no worries. The case had two holes in it for antenna pigtails and plenty of room for the various PCMCIA cards I wanted.

I stuck in spare WiFi card I had lying around and hooked it up to the test bench. The unit requires 12v in and luckily I had a bench supply from when we were putting other projects together last year. Hooking up the spare PC with Hyperterminal and the right serial cables (required a m/m null modem db9) produced a boot screen. Excellent!

A few things here for folks who're trying this for the first time: make sure you have your COM ports set up right! By default the Soekris boots up at 19200 8-n-1, while most *nix installations boot into 9600 8-n-1. This means either you'll see garbage followed by your bootup info, or you'll see the BIOS startup followed by garbage. Your best bet here is to make the two speeds match. Since ost all network gear has a standard of 9600bps it's best to change the Soekris COMBIOS to match. To do this you press Ctrl-P during bootup and use the monitor to set the baud rate. Type ? to get a list of monitor commands. the one you want is Set ConSpeed=9600.

Now the fun with installing an operating system can begin!

Pebble Linux

Since I'm not much of a Unix guy I wanted something that was mostly ready to go. The group NYC Wireless solved a lot of problems for people trying to set up a Soekris. Their distro, Pebble Linux, is a trimmed down version of the Debian 2.4.26 distro. It's a little old but it works great. The hardest part was getting a system together (in my case, using VirtualPC emulation on my powerbook) that could properly LILO a compact flash card to get the system installed. In short order I had the card in and it booted nicely the first time.

Unfortunately, the wifi card wouldn't come up. Instead of showing up as WLAN0 like the pebble instructions showed it came up as /dev/eth2. This is when I discovered I needed a WiFi card with the Prism2 chipset if I wanted to use the built in host_ap system. Some browsing on the net led me to Metrix Communications as a vendor for the highly recommended Senao NL-2511 mini-pci WiFi card. This one has a strong 200mw transmitter and fits nicely in the internal mini-pci slot on the Soekris mainboard, thus leaving one of my PCMCIA cards free. This would be important later.

Getting Pebble going was the easy part. Tweaking it to do what I wanted was harder. I leaned heavily on my roomate Garth (the resident Unix wiz) as I slowly picked my way through learning the system. At first I tried to get everything in the basic Pebble config up and running:

• Verizon 5220: This was the hard part. It turns out that Pebble doens't have the usbserial.o module in its basic install. I had to recompile the kernel to include it. Simply get on a 2.4.26 host system (I have one in a VirtualPC instance), run your make menuconfig, load the pebble.config file from the pebble distro, edit it to add usbserial/Generic Serial, then compile. Here's the tricky part: when you're done, do a "make modules_install INSTALL_MOD_PATH=/your-temp-area-here/". This will create a module tree in whatever temp area you wish. Then copy both the bzImage kernel and the new modules tree to your Pebble host config, then re-install pebble to a compact flash card. Let the system boot once then run "depmod" with the system mounted read/write (remountrw). Depmod will figure it out. Now add in the 'usbserial' line as per the 5220 Howto and it comes up!
• pppd: Once the box is running /dev/ppp0 properly (as per the howto) there are a few changes one must make. Set the ppp0 interface to turn on automatically at boot time. Have it ignore LCP-echo and set it to Persistant. This way the device tries to dial-in on boot and redial each time it loses connection. The lack of LCP-echo makes it stay online in less-than-ideal signal conditions; your mileage may vary. Another factor to consider is that when the link breaks sometimes the card gets hung in a way it will no longer accept AT commands until you eject and re-insert it. This can be done in software. Just add a script into your "ip-down" action of pppd that runs two commands: cardctl eject 0 and cardctl insert 0. Change it from 0 to 1 depending on which PCMCIA socket you're using (zero is the one farthest away from the mini-pci socket). This way the card will hard-cycle after a hangup and be ready for the next time pppd redials.
• NoCatAuth: This is a captive portal and authenitcation system. It also contains all the firewall rules for protecting the system from the net and the users from each other. It's designed for a public access point where people log in and see a 'splash page' before being allowed out to the net. Though I got it to work I ended up scrapping it as I didn't need a portal system. It was replaced with a few basic iptables commands instead.
• DynDNS: When the system boots and goes online it registers with DynDns's service and sets up a name of my choice. This way I can reach the box from the internet no matter which IP it ended up getting from Verizon. This package runs in the "ip-up" script when the ppp0 interface comes online.

With that I had a basic working system. When the box boots up it dials Verizon and registers with dyndns.org. Wireless (or wired) clients can then use it as an internet link. I had to run it with the case off, though, due to the lack of antennas on the system. Time to fix that.

Hardware work

The rest of the shopping list:

• N-female panel mount to pccard connector for the 2511
• N-female panel mount to Orinoco connector for the 2550 card
• 802.11 magnetic mount antenna, 8db, N-male connector
• Dualband 800/1900 PCS antenna, FMA-male connector
• FMA-male / N-male adapter
• Stepper-bit from Home Depot for dilling panel holes
• 12v cigarette-lighter cable from Radio Shack

(New addition) Here's a ful Bill of Materials, complete with purchasing URLs and prices. I used the sites that I originally bought the pieces from. Download the BOM in your choice of format:

Excel | CSV | Tab-delimited | Space-delimited | XML | HTML

Once the pigtails and connectors came in I got the box test-assembled, as shown in the picture to the left. I couldn't make the N-female panel mount connectors fit due to the holes of the default soekris case not quite fitting right. I went down to Home Depot and got the stepper bit. Thank goodness for the drill press! I got the case bored out to the right size for the connectors and got them mounted.

Since I had a second PCMCIA slot free I put a generic USB2.0 card in there and cut a hole in the front of the case so I could plug in USB devices. Since the main serial port is used for the console of the device this was the only way to get other serial data into the box -- such as a GPS. I picked up a generic pl2303 usb/serial cable at Fry's and compiled the kernel yet again to include the pl2303.o module this time.

With the case buttoned up the install looks nice and clean:

Now, on to testing!

• << Previous Page
• Project Home
• Next Page >>

_{Contacts: Tor Amundson and Garth Minette . Questions, suggestions and criticisms appreciated! Flames will most likely be snickered at.}

This work is licensed under a Creative Commons License.