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The Mesh Potato

Issue 188

From Issue #188
December 2009

Dec 01, 2009  By David Rowe
 in
What do you call an 802.11bg mesh router with a single FXS port that automatically forms a peer-to-peer network and relays telephone calls without landlines or cell-phone towers? A Mesh Potato, of course.
Testing and Lessons Learned

We spent some time setting up mesh networks and testing the limits of the system by listening to voice quality. Using the B.A.T.M.A.N. debug modes, we could see the mesh hops go around corners and through windows to relay calls from one node to another.

We still have a lot to learn about everything that affects call quality. There are many factors, such as Wi-Fi propagation, antennas, speech coding, jitter buffers, interference and system load. We are planning a small R&D project to study and optimise call quality in marginal conditions.

We need effective ways to instruct people on how to set up a reliable mesh network (like a picture book or videos or real-time metrics of quality such as a GUI or dialtone).

Wandering around in the South African winter sunshine with a Mesh Potato and a battery, I had an “ah-ha” moment that frankly sent shivers down my spine. This thing really works! You sometimes lose track of the big picture when you are engineering all the details.

Our big goal now is to simplify the installation and configuration as much as possible. At the workshop, we spent some time trying to get a Mesh Potato connected to an Asterisk server, and it was the usual time-consuming Asterisk conf file and command-line frustration. It's hard the first time, but gets easier as you gain experience. However, we want to make Village Telco setup easy for thousands of first-time users. This experience drove the point home: we need to make configuration as straightforward as possible.

Production Potatoes

It has been a pleasure to work with the Shuttleworth Foundation, Elektra and Atcom on this project. We also have had amazing input from the participants in the two Village Telco Workshops and members of the Village Telco Google Group. And, we still have a lot to do. By early 2010, we plan to resolve the remaining calibration issues, perform Beta trials and obtain type approval for the Mesh Potato. At the higher levels of the Village Telco Project, we need to integrate a billing system and the Afrimesh GUI, and integrate into a simple one-click installation.

I am confident we will achieve this and more. We have shown that a small, talented team can develop custom Wi-Fi hardware specifically for their needs. Community-based product development for community-based telephony—how cool is that!

Resources

Village Telco: villagetelco.org

Mobile Phones and Walled Gardens: manypossibilities.net/2009/01/why-wifi-in-africa

B.A.T.M.A.N.: open-mesh.org

Oslec Echo Canceller: rowetel.com/ucasterisk/oslec.html

Atcom: atcom.cn

IP04 Open Hardware IP-PBX: rowetel.com/ucasterisk

Afrimesh Mesh Network GUI: code.google.com/p/afrimesh

Village Telco Google Group: groups.google.com/group/village-telco-dev

David Rowe has 20 years' experience in the development of DSP-based telephony and sat-com hardware/software. In 2005, David founded the Free Telephony Project (www.rowetel.com/ucasterisk), which has pioneered the field of open hardware embedded VoIP products. His open-source contributions include the first open telephony hardware drivers in 1999 and the Oslec echo canceller (www.rowetel.com/ucasterisk/oslec.html). David's other interests include building and advocating electric vehicles and VoIP technology for the developing world.

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The best Mesh / Telecoms Idea I have ever heard of...

www.BnetWifi.com's picture
Submitted by www.BnetWifi.com (not verified) on Mon, 09/20/2010 - 10:59.

Have been installing some Open-Mesh networks in low income areas as well as local small network groups and this combined Mesh CPE and Voip ATA is the best invention I have seen since the Meraki Mini. (or OM1 - lol)

I cant wait to test some of these.

Congratulations from www.bnetwifi.com Spain.

PS: Please tell me how I can test some Patatas and your Dashboard Control / Provisioning System: bnetwifi@gmail.com

Encryption

Bad Cyborg's picture
Submitted by Bad Cyborg (not verified) on Fri, 07/30/2010 - 16:28.

Since the analog signals from the phones are digitized, is there any encryption to at least keep the casual evesdroppers at bay?

Also is there any way that one could buy an unpopulated PC board, any proprietary chips and a parts list for the rest to make one at home? This looks like a really interesting way to establish a small, localized phone system.

Also, IIRC there was an ethernet block on the system diagram. Does that mean this thing could function as an RF LAN/WAN? If that were so secure comm could be handled by encrypting VOIP on a laptop.

ultrawideband?

Anonymous's picture
Submitted by Anonymous (not verified) on Mon, 07/26/2010 - 20:49.

This is a very cool device, kudos! I just got to wondering though...what would it be like to use ultrawideband? From what I've read, it's possible to get a lot more data throughput with a lot less power. The FCC doesn't allow it in the U.S. but maybe in the third world that won't be an issue...and it would be nice if they paved the way for us!

Digital Comm on Version of Mesh Potato

Jon Roland's picture
Submitted by Jon Roland (not verified) on Thu, 12/03/2009 - 20:54.

Mesh networking for analog phones is a good concept, but to be broadly useful it also needs to support digital communications, with computers or smart phones as the client devices. It would seem what while developing them, you ought to go ahead and enable them for broader uses.

My concern is emergency disaster situations, and here in the U.S., as elsewhere, emergency response will require the conveyance of data as well as voice. I have been involved in some disasters and data communications proved to actually be more important than voice communication. From maps to inventories, logistic control to medical imaging, ground-penetrating radar to biometric identification. The list goes on. We can use CB or handheld shortwave for voice. Data is the main need.

Data Comm on the Potato

Anonymous's picture
Submitted by Anonymous (not verified) on Fri, 07/30/2010 - 16:20.

The block diagram indicated an ethernet connection. That should take care of data transport needs.

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