Keith is right. There really just isn't enough ambient radiated energy out there to power/charge even a low power device such as MP3 players or cell phones. The efficiency factor just isn't there. Even if it was, I doubt there would be nearly enough energy in most areas (Council Crest/Sylvan/Skyline areas excluded).
So unless you plan on hanging out around MegaWatt transmitters all day, forget it. Tyler Booth // President ph. 503.548.2000 | fx. 503.548.2002 921 SW Washington St, Suite 224 Portland OR 97205 On Jun 9, 2009, at 11:36 PM, Keith Lofstrom wrote: > > Keith wrote: >>> For comparison, 50mW is what you can collect with a 10% >>> efficient, 1 inch square solar cell on a sunny day, or >>> a 10 inch square cell on a darkly cloudy day. >> > On Tue, Jun 09, 2009 at 03:23:57PM -0700, Daniel Johnson wrote: >> Do you mean 10 square inches, or 10 inches, by 10 inches (100 >> square inches)? > > 100 square inches, or (10 inches) squared . Light levels on > a full sunny day are about 100,000 lux, on a dark cloudy day > about 1000 lux, average indoor home lighting about 100 lux, > a full moon about 1 lux, and a clear moonless starlit night > about 0.001 lux. The eye is wonderfully logarithmic, power > from solar cells not so much. > > So a solar cell producing 5W (for a full access point) on a dark > cloudy day would be about 100 inches on a side. On a moonless > starlit night, you would need a light collecting area 800 feet > on a side. Solar cells leak, so at some point you can't collect > enough light to overcome the leakage. > > A lot of energy collection schemes fail when you do the numbers. > Energy is a quantitative, not a qualitative, game. > > Keith > > -- > Keith Lofstrom [email protected] Voice (503)-520-1993 > KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in > Silicon" > Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs > > > > --~--~---------~--~----~------------~-------~--~----~ The Personal Telco Project - http://www.personaltelco.net/ Donate to PTP: http://www.personaltelco.net/donate Archives: http://news.gmane.org/gmane.network.wireless.portland.general/ Etiquette: http://www.personaltelco.net/index.cgi/MailingListEtiquette List information: http://lists.personaltelco.net To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] -~----------~----~----~----~------~----~------~--~---
