Stompbox – Howto #2 – Getting The Hardware

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.


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.

Soekris 4521

The Soekris 4521 is a nice choice for this project because of it's simplicity, size, and power requirements. I've run mine directly off the 12V jack in my car but use a left over 14VDC wall wart at home. Just about any DC power supply with 12 volts or more (but not too much more) will work fine. Check to make sure the center (tip) is positive. The 4521 pops up on eBay every now and again, but not with much regularity. If you get lucky and find one, the demand doesn't seem too high and you should get a bargain. Try to get one with a case, but you may be able to order that seperately from Soekris if you have to.

I'm sure there are other, maybe better, hardware choices out there, but I haven't found one that's as nice for the money as this.


There is almost always one of these available on ebay. You can choose either a PCMCIA or miniPCI version of this card, but I'd recommend the later. The Senao chipset broadcasts at 200mW and should provide a barely legal signal with most rubber ducky antennas. If you go with a high gain omni-directional antenna don't tell the FCC. I borrowed the antennas off my idle linksys router and they are working fine.

Any other wifi card with the Prism 2/2.5/3 chipset should work but be careful what you buy as most manufacturers switch chipsets throughout the life of their product. I decided to play it safe and just get the miniPCI version of the Senao off eBay. The retail price is usually over $70 plus shipping so I think I got a reasonable deal.

CF Card

Any CF card should work. The official stompbox image, and my image currently require a 128MB card. Your milage may vary with the use of larger cards. I do plan to make a 256MB image to work from at some point but that could take a while.

  • Grocery Store - $14.99
  • eBay - Shipping should be more than the card.

Cables, Wires and Stuff

U.FL to RP-TNCI got all these from eBay so linking to a source is a bit difficult but I'll try. If you use a miniPCI wif card you'll most likely need something to convert from the card's U.FL jack to the plug end of your antenna or coax. I found a pair of U.FL to RP-TNC Bulkead (screws into the holes in the stompbox) pigtails on eBay for $25 from Coax Warehouse. The PC 5220 pigtail and antenna came from C.A.W. Direct, just search their store for the card you have (e.g. PC5220 antenna).

  • U.FL to RP-TNC Bulkhead - $25
  • PC5220 to Antenna - $20
  • Dual Band Cellular Antenna - $20+

Both of these companies treated me well and shipped promptly. Their feedback on eBay suggests that they do this for everone so I feel confident recommending them.

Serial Cable

The Soekris boards use a serial console so you'll need some way to hook it up. You'll probably need a USB to RS-232 adapter unless your machine actually has an "old-fashioned" serial port. You'll also need a null modem cable. Check eBay or Radio-Shack if you don't know have one already. Some sort of terminal software will be needed also. I use minicom which is available for every Linux distro I've ever used. Again I had both these items in a drawer so I didn't have to go hunting.


GPS, Webcam, another wifi card for wardriving, audio out and an FM transmitter, or maybe a serial LCD with lcdproc to display bandwidth use. Let your imagination run wild while I write part 3 and I'll see about posting some addendums with info on one or more of these ideas.

Please post any questions or ideas that you have as acomment below.

Part 1 - Before You Start
Part 2 - Getting The Hardware
Part 3 - First Boot
Part 4 - Config and Customize
Part 5 - Future Plans
Part 6 - Summary

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