Anton’s Stuff

I gave my first stompbox presenation at the XCSSA meeting in San Antonio tonight. It was a good mix of old and young geeks, mostly hardware afficianados with a love of the non-standard.

I hope everyone enjoyed my first attempt at presenting to a user group. it was good to meet new people and I’ll definitely try to attend future meetings. XCSSA meets at 7pm on the 3rd Monday of every month in the Nail Technical Center, San Antonio College.

Rich Jennings presented the the Cubix embedded computer stack. It’s 1.5″ square, runs an ARM[?] processor with 256K of RAM and 2MB of flash. Power consumption is under 100mA for most applications. It runs the open source eCos OS and can be programmed with a number of free and commercial applications.
Nate brought his Nokia 770. The 770 is now officially on my want it now but will have to wait list. It runs a variant of debian complied for the ARM processor and has a lot of potential. The LCD is amazing for a pocket display with fonts that work great in an xterm. Bluetooth and WIFI round out the connectivity getting you to the net and allowing use of a bluetooth keyboard.

Price

It’s quite expensive for a toy. I had a hard time justifying the cost to myself but the old laptop I was using had some issues and I didn’t expect it to last long. My wife wasn’t too happy with the expense but she got over it this weekend when she was able to surf the web and IM with people while we drove 4 hours to Galveston.

If cost is a real concern, just get the evdo card and plug it into your laptop. The next option is one of the commercial 3G routers that can be up and running for under $300. It’s probably possible to do the stompbox for under $500 but it’d be tough and you’d have to scrounge a lot of parts.

Value

The stompbox is a solid and robust solution. I don’t have experience with any of the cheaper commercial routers but would expect them to be as reliable and nearly as solid. One thing the stompbox offers is endless configuration and software options. It’s 133Mhz 486 processor and 64MB of RAM make it powerful enough to run a large selection of applications. If you’ve got some Linux experience, time, and a few C-notes to burn then I’d suggest giving it a try. The project has and continues to be fun.

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USB

My very next step is a PCMCIA USB adapter. Fortunately these things aren’t too expensive if you’re patient on ebay. I may even build a small 5V power supply that taps off the 12V in to allow more devices. From this point on any other peripherals will have to be USB or RS-232. The obvious advantage of USB is that the device can be powered by the port.

GPS

Now what good is a mobile router if it doesn’t know where itself is? The original stompbox image supports gpsd and I plan to get one of the small “gps mice” that are on ebay for $50-60. Once we know where we are and export that information with gpsd we can use a wide range of scripts or apps to access it. A laptop running linux in the car can get gps data over the wifi, we can send the data off to a web server for real-time vehicle tracking and we can also log to a local disk for some war driving logs.

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Configuration

By now you should have a login prompt in your serial console. Login as root, no password and run the stompbox config script, /usr/local/bin/initial-setup. The questions are pretty self explanatory. If you don’t know the answer to a question, take the default. I don’t have a camera or gpsd setup but it still asked me to configure those items. I just hit enter on the defaults to keep going. I do recommend getting a dynDNS account and entering that info. It makes it a lot easier to get to your stompbox from the real world. If you don’t want to mess with dynDNS then just enter something and we can disable it later. When the script is done you should reboot the box.

The setup script fails to update /etc/resolv.conf so you’ll need to do that before you can get along with much else. Put the box in RW mode (remountrw) and vi /etc/resolv.conf. Change the IP of the nameserver to the local wifi address (127.0.0.1 should work too). If everything went well you now have a working stompbox.

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Boot Media

You’ll need a 128MB CF card and a card reader for your computer. I would think a larger card would work but many people say otherwise on the forums. I happened to have a 128MB card left from my last camera and a Sandisk USB reader so I didn’t have to buy either. I plan to make a 256MB verson just because the extra room might be handy in the future but I’m sure I won’t get around to it until I really need it.

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General Hardware Requirements

You’ll need some form of EVDO card with an external antenna jack, an 802.11b card with the Prism 2/2.5/3 chipset, and a small computer with interfaces for both. The Soekris 4521 fits this need nicely without a lot of money. It’s configured with two PCMCIA slots and one miniPCI slot.

EVDO

Your best choice for EVDO service will vary depending on location and budget. I’m using Verizon’s Broadband Access for $80/mo which drops back to 1xRTT when I’m out of the broadband areas. I originally had the Audiovox PC5470 (no antenna jack) but switched it out with an older PC5220 that I snagged off eBay for $20. CAUTION: watch out for the auctions that sell the card cheap with a contract unless that’s what you want. There are “better” cards than the 5220 and they should all work, but make sure it’s got an external antenna jack. Google around to make sure the card and service work with Linux before spending the money and comitting to a contact. Verizon makes it easy to switch cards online, no need to talk to anyone.

• eBay - $20
• Verizon - $150 with a 2 year contract
• Booster-Antenna.com - $110 (Lots of positive feedback on the forums)

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This is the start of my Stompbox Network howto. I have 6 parts planned so far, but may add a couple more later when I add GPS and a Webcam to my stompbox.

Why A Stompbox

The first thing to ask is if you really need one of these, and I suppose the second is can you really afford one. Odds are that you don’t really NEED mobile internet everywhere you go, but for those of us who do and anyone with money for toys, then this can be a cool project. This is not a cheap $50 Linksys router hack. It is built on a solid industrial grade platform and the cost reflects that. My total cost to date is around $400, excluding the initial cost of the EVDO and cellular antennas. The monthly cost for Verizon EVDO is $80 and you’ll most likely need to sign a two year contract to get a new card for cheap. If you have a voice plan with Verizon you may be able to get the monthly cost down to $60, check the forums for details.

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I received the Senao Net2511 MP WiFi card in the mail yesterday and the stompbox booted right up into AP mode. The card’s got a 200mW transmitter and should belt out the signal quite well, even with the antennas I stole from my WRT-54G. One of these days I’ll take the laptop out in the field and see how far it reaches.

I also re-installed the Stompbox image and reconfiguring it just to back out a few mistakes I’d made. Just for reference, if you happen to use the Stompbox image, do NOT “apt-get update” or you’ll get an upgraded glib6 with your next install which chews up almost all of the space remaining on the CF card and causes library issues with some of the stripped down packages, most notably dpkg.

It’s a good idea to backup the image frequently to make restoring easy. I used “dd if=/dev/sda of=stomp.img bs=8192 count=15648″ to make the backup. The count is important as devices don’t always have an EOF to mark when to quit and dd isn’t smart enough to see the seek errors.

OpenVPN is now installed using a back ported package to woody although I don’t think it’s very happy with the config I copied from my old router. Right now it connects fine but dies of a SIGUSR1 every 30 seconds. I can’t see how anything local is giving the sig, so I’m assuming it’s something internal to the openvpn process. (USR1 is the signal used to ask the daemon to reconnect.) The server logs don’t seem to indicate any problems so I’m pretty sure it’s the client.

I’ve got some pictures up on Flickr now.

The scripts are coming along and it now tells my webserver every time it reconnects.  I managed to screw it all up once, but it only took half an hour to get the disk image back to where I was.  Many thanks to the backups.

The miniPCI WIFI card is on the way and I’ve started looking for a PCMCIA to USB adapter.  They are cheap enough on ebay and in surplus bins but I’m looking for one that isn’t too big.

I may eventually try to wedge a laptop drive under the pcmcia cards and power it with one of the small ide to usb adapters.  If anyone has any experience with them please comment with a quick review.

I’m in the process of converting all the computers in the house to wireless so that silly Cat5 will soom be gone

Found a cheap source of U.FL to RP-TNC Bulkhead connectors. I’ll use this to attach a couple rubber ducky antennas to the stompbox once I get the Senao minipci wifi card. Total price is $25 shipped for two of them. I’ll update this post when I receive them and can comment on the quality and shipping time.

http://stores.ebay.com/Coax-Warehouse

Search for “bkhd”.

[update March 22, 2006]

I got the pigtails in the mail today and they look great.  They fit the keyed hole in the Soekris case nicely.  Now I just need the minipci wifi card.

I ended up drilling a hole for the EVDO pigtail to pass through with a grommet.  I’ll post about it tomorrow night after I get the pics on Flickr.