Pebble Linux: Debian on a Wi-Fi diet

By Kurt Starsinic

Access points are commodities. Epinons lists 659 of them. ( If you want to set up a public access point, however, you'll need something that gives you a high level of functionality and control, in a compact and reliable system. Something, of course, that runs on a form of Linux.

Pebble Linux ( is a tiny Debian-based Linux that's the basis of a load-and-go, fully-featured, (relatively) easy-to-customize, no-moving-parts AP. Created by Terry Schmidt of NYCwireless (, and maintained by a pack of user/hackers, Pebble is not a distro in the strict sense. It's Debian, stripped down to a size and shape that will fit cozily on a 64MB flash card. Since it's Debian, adding and removing packages is relatively easy.

Here's how Terry Schmidt says he did it.

I stripped out all the documentation, all the Perl stuff, a lot of the binaries, all the packages I didn't think were necessary. Basically, I just kept deleting files to see what didn't work. I got it down to 44 megs.

I created it because the next thing up from a boot floppy distro is the CD-ROM distro, which can run something like 600 megs. Then the next step up is the full install, which is about 2 gigs. So I wanted the functionality of a real distro like Debian in a size that would fit in a compact flash in something like a Soekris box. I could do apt-get install apache and bang, we'd have Apache. So the full package manager is there, with all the ease and functionality you'd expect.

Terry's README file adds,

It's biggest advantage is that it mounts read-only. You don't have to worry as much about wearing down the compact flash, and you don't have to worry about doing proper shutdowns. Unplug and plug in as much as you want.

There are two packages in a base Pebble image that aren't installed as Debian packages:

There are also a few custom convenience scripts:

Three optional packages are also available:

Pebble will run well on a 486 processor or better, and requires no more than 32MB of RAM and 128MB of "disk" storage. It will probably run on that old 486 in your closet, but for less than $300, you can buy the very cool and very tiny Soekris 4511-20 ( and a wireless card -- and be up and running in no time, If you're hard-core, you can buy the Soekris with no power supply and case and build your AP for less than $250. It's also reportedly run on --

Here's a list of what Pebble includes:

Pebble is designed to work out-of-the-box with any Intersil Prism2 or Prism2.5-based 802.11b card, such as the Linksys WPC11, the D-Link DWL-650, or the Compaq WL100 and WL200. With some simple configuration, it should work with any Linux-supported 802.11b card.

When you're ready to get started with Pebble, see the project site. There you'll find links to:

As an alternative to Pebble for the truly minimal-minded, you might consider WISP-Dist (Wireless ISP Distribution -- WISP is incredibly tiny; it will fit on an 8MB flash ROM and 16MB of RAM. It's not nearly as full-featured as Pebble (it's a really-vanilla AP), nor is it as easy to customize. But you want to run an AP on a clock radio or a PDA, WISP-Dist is probably the best place to start.


I sent out a call to the Pebble list, to see who was using Pebble, where, and why. Here are a couple samples:

Making it happen

To set up your own public AP, all you need is:

  1. An ISP that doesn't care if you share bandwidth
  2. An AP
  3. A target service area
  4. A directional antenna
  5. Motivation

EULAs (End User License Agreements) vary widely from one ISP to the next. Some, like in New York, are glad to let you share the bandwidth you pay for. Others, like Time-Warner Cable and AT&T Broadband, will crack down on users sharing bandwidth over wi-fi. ( A local (or not-so-local) public-Wi-Fi organization can help you locate an ISP with suitable terms of service, or help you to lobby your ISP to change their terms of service. ( can help you find your nearest public-Wi-Fi group. (See the Links sidebar for more listings.)

NYCwireless' mission is to target outdoor public spaces, such as parks. Placement means everything. As Doc and Britt discovered when trying to reach Tudor City's park from high in a building half a block away, distance is a problem. A highly directional antenna can help by concentrating energy in a narrow beam, but a nearby omni antenna will outperform a distant directional antenna nearly every time. Bryant Park is served from a number of points by a combination of omni and sector (directional) antennas on the tops of kiosk buildings. City Hall Park is much better served by a sector antenna on the J&R store across the street. Verizon gets great curbside service from simple omni antennas on public phone booths.

Antennas are not commodities, but they don't have to be expensive, either. And sometimes just putting an AP in a window will do the job. Ben Hammersly did exactlly that for Kynance Mews in London, and served a whole street, including two oudoor cafes.

Motivation, of course, is up to you.