FabFi Wireless

Backhaul One! (or, Mountain View, you've been FabFi'ed)

noreply@blogger.com (Amy) — Sun, 05 Sep 2010 10:23:00 +0000

Wanachi Tower to Mountain View Health Center backhaul downlink: SUCCESS!

Here's happy John. John is happy because the devices have linked and he's strapping in a FabFi reflector which has made a 15dB improvement in the signal.

Great signal. Left devices in place.

Heath Center is a great site. Tons of community focus and welcoming staff and management. Was approached by interested, friendly, and eager random public while working. Wanachi guys and management have been unbelievably helpful and enthusiastic (especially in comparison to the recent days of firewall-ish frustration with UoN ICT).

Linux Tom peaking at the Mountain View health center

FabFi playing with the big boys on the Lavington tower.

Amy tired. More later.

ps - did I mention there's a JoinAfrica Facebook group?

Welcome JoinAfrica Bloggers!

pedalandwrench@gmail.com (The Wrench) — Sun, 05 Sep 2010 09:59:00 +0000

You may have noticed the appearance of (fab) Amy on the blog. Over the next few weeks you'll also see the debut of the rest of the JoinAfrica team:

soulstar - (Linux) Tom, from UoN Fablab
OnsomuOchoti - John from UoN Fablab
lusrandi - Nicholas from UoN fablab
antoinevg - Antoine from Afrimesh

Backhauled at Last

pedalandwrench@gmail.com (The Wrench) — Sat, 04 Sep 2010 16:09:00 +0000

Today was a big day for JoinAfrica. After spending most of this week struggling with the IT department at University of Nairobi (UoN), today was a welcome and refreshing change--a connection to the interwebs. While you might be thinking this isn't such a big deal, here's a little context:

For the last week the Fablab team has been working 14 hour days configuring devices and preparing materials to deploy a wireless network at a UoN campus. The team deployed their network on Wednesday, and by the end of the day Friday had yet to receive an uplink. UoN's IT department cited inadequate communication of plans and exclusive behavior as an excuse for refusing the connection despite failing to attend any work, meeting, or briefing sessions at the fablab, to all of which they were explicitly invited.

The IT dept. must have been fully occupied making a fuss over our project because the internet in the lab was completely down for at least a half hour each day this week, and down for more than ten hours on Friday.

In less than the number of man-hours wasted waiting for UoN IT Wednesday through Friday, the team designed a reflector mount to accept a new device, planned a ptp link and connected a remote site to 5Mbps of generously donated Wananchi bandwidth across 3.5km to Mountain View. Not only did Wananchi donate bandwidth to the project with little more than a handshake on our research data being open-access, they also lent us tower space and two pairs of helping hands on a Saturday to git-er-done. Meanwhile UoN IT continues to frustrate the efforts of its own students to provide wifi on part of their campus.

With some great help from David and Ken of Wananchi, we linked up with a nanostation5M-loco at -56dBm, putting the gain of the big fabfi reflector at 15dBm over the stock device.

Thanks, Wananchi. We all appreciate your support of the Fablab's hard work.

As Amy alluded to her in post today, the remote end of our link is an excellent community hub bringing access to a health center, schools and residential communities across multiple socio-economic strata. The vision for this location is to provide local and educational content from the KENET/UoN system as a free service in parallel with a paid premium service on the commercial link, both serving the KENET outreach mandate and providing a valuable community resource. That is, if someone at UoN will get us an IP that works...

Join Africa pilot site selection in Nairobi

noreply@blogger.com (Amy) — Fri, 03 Sep 2010 23:38:00 +0000

In an earlier post I casually said "Mountain View area wins for a lot of reasons". That has been challenged several times over these few short days as technical and social impediments come and go. It's been a roller coaster of commitment to then away from downlink and uplink sites.

Yesterday we sketched it out in a KTA-style analysis and wiggled the weights of each category. The surprising thing is that revenue-making ease doesn't push one site above another, and until you really weigh one aspect heavily, no site completely dominates (though some outright suck).

That is, until Keith and Nick discovered the health center at Mountain View this morning.

Fnd killer spot in mt view

That's the text message I got from Keith.

The health center has terrific, unobstructed line-of-sight (LOS) to a Wanachi tower and is on a higher part of the upward slope of Mountain View. Nick cold-called the management of the health center and got us permission to do a point-to-point downlink test from Wanachi's tower Saturday morning.

We're going to be here pretty late tonight making and configuring the equipment.

What geeks do on a Friday night

noreply@blogger.com (Amy) — Fri, 03 Sep 2010 22:48:00 +0000

Tom's such a trooper. I'm not sure if he's running on pure muscle memory or he's got a secret coffee IV that he's not sharing. Here he's on something like Ubiquity device 16 of 20:

Tom Okite is determined to flash all the devices in one night for the entire Kisumu deploy.

He's not alone here tonight. Shopbot Tom is making a pair of large reflectors for tomorrow morning's Wanachi Tower to Mountain View health center test shot.

Shopbot Tom is a master of press-fit. Here he's making the feed arm for the Ubiquity nanostation which needs to be at a funny angle. The odd looking mast was previously used to move the angle of the arm from behind the reflector to find the precise angle with the best signal.

Kisumu area deployment sketch

pedalandwrench@gmail.com (The Wrench) — Fri, 03 Sep 2010 08:33:00 +0000

POE hack on Linksys (doesn't work)

noreply@blogger.com (Amy) — Thu, 02 Sep 2010 08:55:00 +0000

The intent was to modify a Linksys router/AP to also serve as a power over ethernet (POE) distribution hub as well. I was so convinced it'd be ok that I didn't first measure to see if those pins were internally wired to something else.

They are.

POE distribution hack on a Linksys: don't do this at home. Seriously.

Recorded for posterity: "this doesn't work". I didn't smoke the box but the jacks got really hot. I unsoldered everything and measured a few hundred ohms between "POE+" and "POE-" pins. Darn.

And oh, I did the above soldering with a AA-battery powered Weller BP860MP. It worked ok, but my button-holding-down-finger hurts.

we’re starting the “live” system deploy tomorrow, uh, today

pedalandwrench@gmail.com (The Wrench) — Wed, 01 Sep 2010 19:24:00 +0000

Cross posted from Amy. I love it when she does all the writing for me...

For the past 3 weeks or so, Nipun, Nick and others have been running about Nairobi scouting and getting permissions to mount FabFi equipment on towers and roofs as well as connections into the internet. They’ve settled on some sites which broadly speaking are the Mountain View area (which includes some of Kangemi) and Loresho (and some of Kangemi).

Mountain View and Loresho are the two possible areas for the pilot. The orange circles are internet uplinks for the network.

We wanted to make the backhaul connections along schools and examined the communities near Nairobi School and Kangemi School. In both cases we could see different socioeconomic strata pressed up against each other and somewhat well mixed.

Planned community (upper left corner), slums, and estates. The community near Kebete.

There's some distance between Nairobi school and where people live.

We had to choose one of the areas to build out first. Making the 5 GHz backhaul among the main repeater sites and the internet uplinks as well as making local omnidirectional 2.4 GHz wireless AP’s at each repeater site consumes approximately 1/3 of the devices we budgeted. We estimate that building out any one area will consume the remainder of the devices. So it seems we must chose one area to build first and use the profits from the first to buy the devices to build out the second.

For many reasons the Mountain View area wins. We’re now prioritizing building up expanded access around Kangemi school and Mountain View areas. The technical team now mostly turns to getting equipment up and working.

Nipun has a homework assignment to work the numbers to figure out what the price(s) should be for the paid “Premium Service Level” – that’s how we make our nut. Here’s his assignment, I’m sure you b-school folks will get all kinds of excited.

The analysis has two components:

1) Determine long-term “sustainable” pricing for the system based on going tier1 bandwidth rates. This is for the conservative case where we’re collecting no revenue other than from selling bandwidth.

2) Assuming free bandwidth, what do we have to price at in order to finance duplicating our current deployment in three months? (see hardware cost below)

Here are the inputs:

- Residential market price for bandwidth @1Mbps (assuming 1/3 of operator cost is bandwidth this is about a 20:1 contention ratio) = 4,999KES/mo (zuku)

- Going rate for backhaul (tier 1) = 32,730KES/(Mbit*mo)

- We should have a contention ratio the same or better than other providers

- Deployment to Kabete / Mountain View with backhaul will consume ~810,250KES worth of hardware (attached is a potential coverage map).

- We assume about 10% of the bandwidth will be consumed by “free” customers (but we don’t know. Maybe your analysis will dictate QoS rules…)

Assume the average device must be replaced once every three years

Required outputs are prices for access-cards of the following duration:

- 1 day

- 1 week

- 1 month

In long-term case fees will have to cover:

- Bandwidth costs

- Staff (150,000KES/mo)

- Local Transport (black van with no windows…)

- Overhead (legal, g&a, etc)

- Maintain physical system

- Expand physical footprint on a reasonable timescale

Short term, we’re only concerned with making 810,250 KES above our costs, after staff in 3mo.

Our model is that you can always connect for free using the unused part of the bandwidth. Wikipedia and some domains such as .edu, .edu.ke, .gov, some locally mirrored content such as MIT’s Open Course Ware, and similar resource information type sites are exceptions – they aren’t ever limited. You can also pay for Premium service which is faster since you are guaranteed some level of service. If that sounds impossible, the intrepid folks at Afrimesh showed that given free, slower service, people would pay for the faster service in an earlier implementation in Scarborough, Cape Town, South Africa, reaching profitability about a year ago!

Organizing the FabFi equipment for tomorrow's deploy in Lower Kebete.

Tomorrow we’ll be doing a three-point backhaul deployment at the UoN Lower Kebete School of Business tomorrow (connecting their Admin building, library, and student center). It’s mostly a training and deployment preparedness shakedown and each 5 GHz backhaul site will require something unique, for example a solar panel at the student center, hacking a Linksys to provide POE to the Ubiquiti devices at the admin building, and some challenging penetration at the library. And if we still have the energy, we’ll haul a large FabFi up the 12 story radio tower which will ultimately point to Nairobi school and a site in Mountain View.

Shopbot Tom is bleary-eyed after spending all night modifying and cutting out a large FabFi reflector to work with the Ubiquity 5 GHz NanoStation.

Yeay! Now back to my long, long to do list…

shaping the Nairobi Join Africa backhaul network

noreply@blogger.com (Amy) — Tue, 31 Aug 2010 23:07:00 +0000

Ok, look, what can I say, I'm impossibly behind on the blog thing. There's just too much... a million things from Fab 6 and then immediately after a million more things from Maker Faire Nairobi, plus another million from the Join Africa deploy. By my math that makes a "bajillion" and I've been only collapsing into bed without the willpower to tell you about it.

Connection diagram for a Ubiquity device when using AC power

But tonight we're pushing some documentation on to the wiki and I want you to see. This is an image that was made by Tom Okite, Hansel Omondi and Laurence Ombuki from ARO FabLab Kenya West in Kisumu. They're in Nairobi this week to help deploy the Nairobi networks in anticipation of doing the same in Kisumu.

mapping out the back haul sites and internet connection points in Nairobi

You can find the (in work) gallery at: http://www.fablab.is/w/index.php/Power-over-ethernet_diagrams.

And go here a little more on the FabFi and Afrimesh project we're calling Join Africa.

Fabfi and Afrimesh: Building a Wireless Africa

pedalandwrench@gmail.com (The Wrench) — Sat, 28 Aug 2010 08:18:00 +0000

Fabfi, the open source platform for building large-scale mesh wireless network infrastructure, and Afrimesh, the platform-agnostic, open dashboard for network management, have joined forces to build a turnkey platform for deploying, managing and monetising high-speed data networks under the codename JoinAfrica.
Over the last few weeks, we have completely overhauled the Fabfi platform in anticipation of a pilot project near Nairobi Kenya. After some feverish last-minute work, we're also providing wireless at Maker Faire (it's beta, so please use it and tell us if you notice anything that's not working right)

SSID Makernet by Fabfi
User: pamoja
Password: JoinAfrica Note: no proxy is required

For those of you reading from afar, this page is being used as our info page at MakerFaire Africa, so it might seem strangely like an advert... because it is.

Kenya, Week 1

pedalandwrench@gmail.com (The Wrench) — Wed, 18 Aug 2010 22:53:00 +0000

The first week of the Keyna deploy was, in a word, intense. The Nairobi lab has a great group of talented [super] users, and it was easy to fill the roles of linux geek, project manager, and JOAT (jack of all trades) in the first couple days. It was a good thing as well, because we might have bitten off a little more than we could do for a first week. After very positive meetings with the Permanent Secretary for ICT and university officials, it became clear, that "just getting something up" would not be enough to fully capture the opportunities available. The network not only had to work, but it had to be "hish-performance" in a way that fabfi had never really considered before.

The demand for reliable, high-speed connectivity to end users very high, and in the university/Education environment the desire for locally hosted content is strong enough that sitting behind the uplink speed as an upper requirement for network performance is effectively a cop-out. It turns out, however, that adhoc networks don't support N-speeds, so we spent the week reworking fabfi to support AP/STA operation, debugging the new devices, and upgrading to WPA. It was a great experience in understanding the software, but as of Friday the number of nodes deployed in the field by the crew was exactly 4 -- enough to learn cable making, battery power and basic pointing, but leaving a little too much to the imagination for my comfort. Only time will tell how the list of "needs done" will fare in my absence, but in the meantime off to fab6 for a couple days of much-needed geek R&R.

Best Hotel Spread EVER

pedalandwrench@gmail.com (The Wrench) — Sun, 08 Aug 2010 16:58:00 +0000

Sorry Nipun, you're sleepin' on the floor--cuz if it doesn't all fit in the picture, it certainly doesn't fit in the hallway. Let's go build a series of tubes...

Unrelated travel note, courtesy of the WC at Amsterdam Centraal:

Pay toilets are a disservice to humanity. The idea is noble enough: You want to have a nice bathroom so you charge people some to use it and use the money to keep it from getting crapped up (pun fully intended). The problem with this logic is that when people gotta go, they gotta go. After walking the hundred yards to the WC at the end of the Amsterdam Central train station platform to be thwarted by an electro-mechanical gate that ONLY TAKES EXACT CHANGE, the last thing you're inclined to do is feel respect for city ordinances against public urination. By the smell outside from 30yds away more people have let go on wall of the WC building than inside. Surprised the gate isn't shorted out now.

The moral of the story here is that everyone benefits when certain things are free. Keeping the whazz off the train platform is a pretty clear example, but I don't think certain types of internet access aren't that far behind in today's world. That's sort of why we're here...

Kenya Ho!

pedalandwrench@gmail.com (The Wrench) — Sat, 07 Aug 2010 23:18:00 +0000

On the plane to the Kenya Fablabs with 275lb of wireless gear (most of which can be found in Kenya, for future expansion). Fabfi v4 is gettin' coded in country! Let's just hope Kenyan customs doesn't follow this blog. [Edit: it's all perfectly legal, but it's an easy target for the odd entrepreneurial airport security guy...]

Teaser of things to come

pedalandwrench@gmail.com (The Wrench) — Sat, 24 Jul 2010 21:15:00 +0000

May dad tells me I haven't been blogging much, so it must mean I'm busy. He couldn't be more right...

Fabfi is going to Kenya in August, and there's more to do than I can keep in my head all at once. Amy and I did a little late-night planning session on Friday, and the output was "you're not sleeping 'till September". This looks like it could be the biggest deploy yet, but you'll have to wait for the details. As a wise man once said: "Under-promise. Over-deliver".

Stay tuned.

FabFi MD

pedalandwrench@gmail.com (The Wrench) — Thu, 17 Jun 2010 04:02:00 +0000

With no other viable broadband options in town, Fabfi has recently been providing a valuable service to the public hospital. Once every two weeks, doctors at the public hospital participate in video conferences with doctors in Virginia, who have been providing continuing medical education and practical support. This effort was recently covered by WAVY TV in Virginia. Over 40 physicians gathered at the last conference despite a 7:30am start time

While the Fabfi network has been providing the network to support this great collaboration for over four months, it is frustrating to see the newscaster dismiss the dropping of the skype call, saying, "technology in Afghanistan is unreliable." To do so simply validates the acceptance of low standards that is an epidemic in Afghanistan. "TIA" (This is Afghanistan) is not a reasonable excuse for failing to pay attention to quality and detail. Not only is the problem often outside of Afghanistan (say, with skype) but such a fatalist attitude discourages local attempts at doing better. One doesn't get many diamonds by asking for coal.

Technical note: The skype drop-call problem is likely due to traffic congestion at the internet uplink. As the fabfi team does not have access to the border router, which handles traffic from multiple sources other than fabfi, the team is unable to implement the proper Q0S policies to ensure calls are not dropped.

Amy on NPR and the Fabfi Team

pedalandwrench@gmail.com (The Wrench) — Sat, 17 Apr 2010 19:28:00 +0000

I'm a little late reporting this one, but Amy talked about Fabfi on NPR this Monday. Yeah national news!

It's easy to forget that there are a whole pile of people behind Fabfi besides Amy and Myself. For lack of anything better to say today while the SSF comms team debugs their new setup at the Taj, here are some of the biggest players. They deserve huge props for keeping the boat afloat:

- Hameed Tsal (installer, beta tester)
- Rahmat Sadat (installer, accountant)
- Smari McCarthy (apps development, server admin, European Publicity)
- Andreas Guðmundsson (scary, low-level linux hacker-magic)
- Jesse Krembs (Training, Wireless Network Engineering)
- Kerry Lynn (Hardware Hacking, field testing, sage advice)
- Kenny Cheung (reflectors that work [new version coming soon?])
- Logan Lynch (Fab-guru)
- Tim Lynch (Logistics, pecan pie, coffee)
- Dr. Dave, Ken K, Team SSF (internet comms uplink)
- Fabfi users (suggestions, learning to diagnose and fix stuff on their own)

Keep the good stuff coming!

Coalition of the Willing 2.0

pedalandwrench@gmail.com (The Wrench) — Sun, 11 Apr 2010 17:19:00 +0000

Today an article about Fabfi was Printed in the in the Sunday edition of the Boston Herald. I was initially very surprised at the paper's interest in the issue. The subject matter is a little outside I would typically associate with the publication, and I wasn't really sure it would resonate with the readership in a way I would be comfortable with. But any publicity is good publicity, right?

As expected, there was some push-back in the comments of the online article of the type "what if this gets into the hands of terrorists?". I could dedicate 10 pages of text to why this fear is an unfounded construction of the mainstream media, but there's not enough time in the day to get on such a big soapbox...

The internet is the most democratic medium the world has ever known. It is the easiest way for individuals to participate in social communities, allows every user to speak his or her mind and knows few national boundaries. Trust and collaboration begins with personal relationships. Personal relationships start with communication. The internet is the medium for that communication. This year Facebook surpassed Google in the amount of traffic it funnels to major news and information sites. Our friends are the most powerful influences in our lives on what we think, how we act, and what we're passionate about. They support us in times of need, and join with us to create the movements that create social change. Why would we not want to make friends in the places we are most worried about?

"Coalition of the Willing" was a common phrase in post-1990 political rhetoric aimed at popularly legitimizing Military or Military-"humanitarian" operations that lacked widespread global support (Iraq being a well-known example). The rhetoric played to the belief that there is power an legitimacy in numbers--a belief well-founded in empirical truth, and one that is the foundation of democratic ethos. However, the original Coalition wasn't much of a coalition, and was definitely not of the "willing" in the traditional sense. The historical record shows that the list of members was retroactively edited and that significant financial coercion was at play in the acquisition of members--as a result it garnered widespread criticism and arguably had little political of operational value.

In the wake of nearly a decade of at-best marginally successful military and development organization attempts at solving the problems of security, infrastructure, governance and civil society, there is a new "Coalition of the Willing" forming. This coalition is made up of young people around the world interested in finding solutions to the problems that the big players have yet to solve. Their efforts are multiplied by digital media. SMS messages have been used to monitor elections. Cell-phone video has exposed brutal acts of extremist groups, and there is a growing interest in digital communication to address the challenges of government accountability (to name only a few applications). The sharing of technological skills between coalition members of different nations creates trust and builds multi-national personal relationships, and the solutions that result are applicable both at home and abroad.

It is a fallacy to believe that it's possible to prevent information access, and an even greater one to believe that such access is a negative force. If it wasn't, totalitarian nations such as China and Iran wouldn't go so far to limit digital communications. Instead of arguing about who might be using digital information to do harm, we should accept the inevitability of ubiquitous information access and focus on how to use that access to teach, organize and create global communities of people who want to do something about the problems they face. End. Rant.

Fabfi 3.0!

pedalandwrench@gmail.com (The Wrench) — Wed, 07 Apr 2010 07:54:00 +0000

At long last, fabfi 3.0 is out in the wild. It's 4am, so I'm gonna keep this short. You can read all the details on the wiki and on the updated website:

New features:

Complete flash images (no more tarballs, yay!)
Remote flashing feature with rudimentary configuration-persistence functionality
Splash page pulls content from central location
Client wiring for Fabfi Dashboard
OLSR Extensions are fully enabled

I do want to harp on one feature, however: the Dashboard.

On the occasions when I'm not developing the-Fi I often go to class. [Part of] Today's topic was "Innovation Climate". In a sentence, an innovation climate is a set of circumstances, policies, resources and industries that together create an environment that encourages innovation. While today Fabfi is largely an internet infrastructure, I [am not alone in] believe[ing] that its real niche is as an active (as opposed to passive) facilitator of learning, innovation, communication and commerce. It is the weather machine of innovation climate creation (ICC).

To me the dashboard is the missing cog in the Fabfi ICC weather machine. It is a means to serve applications and targeted content to users every time they use the network. Applications could be as simple as a network-local "craigslist" or an archive of video tutorials on various topics; or as complex as simplified web publishing services and aggregated local web directories. In either case, the dashboard drives local content and promotes valuable use-modes for the network beyond simply surfing the web. In a places where most people are just learning what the web is, a little packaging goes a long way.

As you may have noticed, the screenshot of the dashboard is remarkably empty as of April 7. If you have a good idea for something to add or some time to lend a web-developing hand please email us (or just send us money so we can eat while we code... ;) )

...and I leave you this morning with a little bit of shameless GIF animation from the website update. It's so shameless it doesn't even fit on the page! (click for big)

The value of failure...

pedalandwrench@gmail.com (The Wrench) — Fri, 02 Apr 2010 03:22:00 +0000

The following is a Guest Post by fellow Fabfi developer Jesse Krembs:

I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison

We as a society don't admire failure. We celebrate success and achievement, the overcoming of adversity and challenge. Yet we rarely, if ever, talk about what doesn't work, or how learning from these failures helps us toward success, and why this is a useful life lesson. In science and in engineering there is a lot of what doesn't work. From the LHC, to the Titanic, to learning the skills and values of a trade, stuff doesn’t work all the time.

So here's one from the Fablab and FabFi project. One of the goals of the project is to develop simple, low cost and easy to create antennas. One of the ways we know we can improve the performance of the Fabfi parabolic antenna is to replace the existing omni with a patch antenna.

Keith made two beautiful antennas' using the Fab Labs laser cutter from acrylic and some stick on copper sheeting. They are really nice looking. We haven't tested them but they probably work really well too! But they require that the builder has a couple of things that not everyone has; namely acrylic sheeting, a laser cutter and stick on copper sheeting. I decided to try and make the same basic thing but with items commonly found.

I managed to dig up some scraps of tinfoil, cardboard, and some white glue. I cut everything out by hand and assembled it. At this point I was thinking “Wow, this looks pretty good so far”
That's when Kerry said
“I don't think you'll be able to solder to that aluminum foil”

But being ever the optimist I tried. And tried, and tried
FAIL!

It really can't be done and lord knows I tried, but what I did learn was amazing:
· The proper website to figure the antenna measurements.

· A bunch of ways to figure out dielectric constants, or where to find a table of them.
· How to put it all together.
· That white glue really does work.
· That you could do the cutting work with hand tools.
· Some of the original designed considerations and characteristics.

What does all that mean? Well for one thing I get to do it again, but this time I get to do it better. Because I learned a bunch of awesome stuff in the first go around. Stay tuned for the next version.

All the way up the pole!

pedalandwrench@gmail.com (The Wrench) — Fri, 02 Apr 2010 02:58:00 +0000

When you hear of a good thing, you'll go a long way to get it. When I saw this, my first question was naturally, how do you aim it once it's already up there?

The answer is move the pole. This one was aimed by tilting and rotating the pole until the signal was peaked and then tied down in the right spot.

Sensing, Information and Accountability

pedalandwrench@gmail.com (The Wrench) — Wed, 31 Mar 2010 12:03:00 +0000

Below is a screenshot from the Fabfi status page a couple days ago. The astute reader will notice that the only nodes on the "backbone" are up. If I had also included screenshots from the proceeding 6 hours you would see blocks of nodes blip off the map one by one and then a few (battery powered?) lingerers clinging to life for some hours before joining the rest of the city in a total blackout.
This got me thinking about data collected by the fabfi network as a means to community and government accountability. The fabfi network is growing rapidly. With over 40 active nodes, the user-base is easily now into the hundreds (considering the size of households and the fact that users often share with neighbors), and with the newest connections is spreading geographically across most of the city. Fabfi is a ready potential forum for collaborative community organization. Network stats data useful for keeping the power on and the air clean? (imagining USB air quality sensors). What is the interface that best facilitates dialog and community building between fabfi users?

Have ideas? Send them our way...

Better reflectors 101

pedalandwrench@gmail.com (The Wrench) — Mon, 29 Mar 2010 02:03:00 +0000

As the news-media seems to have noticed recently, Fablabbers in Jalalabad have been designing and making their own reflectors out of bits and pieces they can pick up cheap, putting reflectors together for less that $3 US. This week brought two more such reflectors online. As you can see, the design is starting to take on a more clearly defined shape and bill of materials. The hole punching in the reflective surface is both functional and artistic, as the holes reduce the wind load on the installation:

Since the Fablabbers are usually reading along, I thought I'd dedicate a post to what makes a good reflector and some nifty ways to make a little bit go a lot farther. I preface this little tutorial with the statement, "I am not an RF engineer" (I am neither a whiz at physics nor a practitioner of voodoo, one of which is usually required for good RF engineers), but I do know a couple of things about making reflectors that are worth sharing.

The basic shape of nearly every dish-like RF receiver you see out in the world is that of a parabola, as shown at right. The unique property of a parabola is that everything entering it perpendicular to its opening is reflected to a single point called the focus similarly to the way a funnel directs all the liquid poured into it into a central hole. By putting your transceiver at the focus, you redirect any RF energy that would have missed your transceiver right back to where it belongs. The drawing above-right is an example of a parabola in a single plane. It will collect and redirect energy to the left and to the right of the focus back to the transceiver.

It is easy to draw a parabola in a single plane without using any math or special tools. All you need is an L-shaped straightedge such as a carpenter's square, a second straightedge, a pencil and some string:

Lay the straightedge on the edge of the surface you want to draw the parabola.
Fix one end of the string to a point you want to be the focal point (F)
Fix the other end of the string to the top of the L-shaped straightedge (B) so that the middle hangs below the focal point as shown in the drawing below
Place your pencil inside the loop.
Slide the L back and forth while holding your pencil against the L. The string will make it go up and down.

Click Here for the Animated version @www.sciences.univ-nantes.fr

A quick look at the latest reflectors shows they are not truly parabolic, nor is the active antenna centered in the design:

These reflectors could be much more powerful with only very simple modifications:

Draw the parabolic shape on the base so that the focal point is at the edge of the wood. Remember to mark the left-right location of the focal point
Shape the metal so it follows the parabola on the base. It may be helpful to draw a parabola on a top-piece as well to make sure the metal stays the same shape all the way up.
Position the router so the ACTIVE antenna is at the focal point (this is the one next to the reset button for the 54G
Be sure to cover the router on all sides to keep it from getting filled with sand in windstorms

A more challenging, but also more effective design might be parabolic in both the horizontal and vertical direction to concentrate energy more efficiently. Hopefully we'll see some creative ideas for this in the future along with modified feed elements and tools for repeatable manufacturing...

Fabfi hackathon - Complete!

pedalandwrench@gmail.com (The Wrench) — Thu, 25 Mar 2010 22:40:00 +0000

Side Note: It's official, FabFi is happening faster than I can blog it out. The last two weeks managed to coalesce interviews for an upcoming Herald article, the Hackathon, and H&R installing a pile of new links. I'll be putting up a post-a-day until I catch up. Here goes post #1:

The goal of FabFi Hackathon 1 was to try to bring the FabFi architecture closer to the ethos of "do more with less". The plan was to look at the system as it exists now, identify what could be improved or repaired, and spend a weekend putting our heads together finding solutions. The following a a summary of what went on, which I will break out into more detailed technical posts over the coming weeks, pushing out what we have and soliciting advice. FABFI NEEDS MORE DEVELOPERS. If you want to help, email us (fabfi [at] fabfolk [dot] com)

A big focus of the weekend was design for local materials in Jalalabad. A major component of the hackathon's success was the participation of Jalalabad users who went out into the city and took pictures of all sorts of raw materials that were cheap and easy to come by, including metals,

plastics,

and different types of wood,

for us to consider when updating RF reflector designs. Our pal Kenny, who developed the original version of the current FabFi reflector, will be back on the case over the next month or so leading a global team to create a new reflector that's cheaper, more powerful and easier to make! In the meantime, Jesse got on the case of characterizing and improving my, as yet untested, rubber-ducky patch antenna feed hack (related post to come).

The real star of the weekend, however, was the ASUS WL-520GU. Now we all love the 54GL. It's a workhorse; it's reliable; and it's already been hacked every which way so you don't have to debug code. Sadly, the 54G will not be around much longer and it's already very difficult to come-by in the middle east. Enter ASUS--smaller, cheaper, comes with USB

and, as the photo above proves, available in Jalalabad at the local DigiTech.

Having just gotten our hands on a crate of 520GUs on Friday, the weekend was open-season for hardware hacks. Kerry wasted no time wiring up the console interface, while Jesse broke out the spectrum analyzer and set about characterizing the radio properties. by Monday we had a working FabFi FW image and a partially functional USB interface, and Jesse was convinced that this box would have as good or better wifi properties than the 54GL. Hameed will be beta testing the new offering and we hope to have a complete package with instructions for the device in a week or so.

In between firmware builds there was also a fair amount of thinking about configuration. The current fabfi infrastructure asks users to select a node number and a channel. While the installers of fabfis all know the overall system and each other, this works just fine, but knowing all the installers doesn't scale to thousands or tens of thousands of nodes. At that level, the network needs to manage itself. We didn't get much farther than a whiteboard on this front, but the ideas are now on the table.

Related to the autoconfiguration thought process, we also installed a local timeserver in Jalalabad and discussed better ways to log usage data. Conclusion: easy + "secure" + reliable don't all fit in the same sentence. Expect this to be a detail post in the coming week.

That's all for now. More to come tomorrow, and the next day, and the next day...

Holy Crap we got /.'ed!!

pedalandwrench@gmail.com (The Wrench) — Fri, 05 Mar 2010 03:16:00 +0000

Well, boingboing'ed to be precise.

...and Gizmodo'ed

...and freerang'ed

...and futurismic'ed

...and then apparently I got on Dutch TV (though I haven't seen it yet)

...and then the web site crashed from all the traffic. Go web 2.0! Jalalabad on the world stage! Cool huh?

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Nasty bug, oops!

pedalandwrench@gmail.com (The Wrench) — Fri, 05 Mar 2010 01:33:00 +0000

Yep, fabfi is officially responsible for the net at my house being terrible for about three months... One stray character in the script that checks the WAN for a gateway results in constant resetting of the network when there is no statically entered gateway (and I think router needed to boot with the gateway entered...). Fortunately, dumb luck kept this from affecting the Jalalabad network uplink. We should get around to writing an auto-updater one of these days...

Bug is now fixed (yay). you can fix any 2.1 router by downloading and running the update script HERE. This will take you from 2.1 to the new current version: 2.1.1. For those of you who still need to get from 2.0 -> 2.1 use this updater before you use the one above.