Green Wi-Fi's Solar Samaritans
January 31, 2008
Off-duty engineers find low-cost ways to make the sun power Wi-Fi in remote locations.
Bigger isn't always better. And from what Bruce Baikie could tell from the solar technology that has been used for Wi-Fi deployments, smaller really would be the ticket to making such technology widely available in developing countries. Specifically, Baikiewho founded the start-up Green WiFi [sic]says big batteries and big solar panels are what the industry generally employs. Partly, that's because installations are designed for running a router at full power all the time, he says.
Looking to find cheaper solutions for areas where electricity was either unreliable or scarce, Baikie, who's based in Berkeley, California, pulled together a volunteer team of Silicon Valley veterans. His own day job is with Sun Microsystems. Together, they set about re-thinking solar powered Wi-Fi networks.
"We've been able to shrink the solar panel down and shrink the battery down so our cost per AP location is about $500," he says, or about one-third the typical cost.
The solution emerged from puzzling out the question of power management. How they did that, Baikie says, is by designing what they call an "intelligent charge controller." It conservers battery power for as long as possible, including reducing the load when demand is low and when the sun goes down. That means the APs can run on a solar panel that is about one foot square, he says, while standard panels are more like three-feet square. The charge controller, called the GW-ICCM, can talk back to the router via an Ethernet connection to relay how much power the battery has. Four different stages of power management allow for efficient consumption. The controller was about a year in the making, Baikie says.
With that one proprietary elementthey've applied for a patentthe group then assembles their networks from standard off-the-shelf components. The Linksys WRT54-GL is "the router of choice as you do these low-cost networks," Baikie says. They build out a simple mesh network. "We just use open-source mesh network software that we load onto the Linux router."
Green WiFi is working with the One Laptop Per Child program to provide wireless solutions in communities where students soon will have Wi-Fi-enabled computers. Baikie's focus is on schools and villages because he sees solar power as a technology that can reliably be harnessed toward the goal of bridging the so-called digital divide.
With some funding from OLPC, Green WiFi is having its first batch of controllers manufactured in Taiwan. Baikie expects installations to begin this year. Though it may seem ironic given the emphasis on underdeveloped villages, the first installation is planned for Honolulu Community College in Hawaii this spring. The object there, Baikie says, is to demonstrate that the technology can support a network without relying on the power grid. It's relevant, because events such as an earthquake, like the one that hit Honolulu two years ago, can knock out all traditional lines of communication.
But after Hawaii, Green WiFi's plans for the year call for installations in four countries in Africa and Southeast Asia.
"2008 will be a big year for us," Baikie says. It stands to be an even bigger year for the users in Senegal, Vietnam, and other countries who may soon have reliable Internet accessand a new use for their plentiful sunshine.
Amy Mayer is a freelance writer and independent radio producer based in Greenfield, Massachusetts. Read and listen to her work at her website.