-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Mike Dawson wrote: > So the force required to generate 9W (e.g. for charging a little and > running the laptop): > > 9 = 0.15F / 2 > F = 120N = 12.23kg (given gravity = 9.81N per kg) > > Which does not seem to be an unreasonable amount...
I applaud your effort, and I look forward to seeing the results. Your calculation is a bit iffy, but the correct biomechanics are messy, and probably not terribly informative. The thing to remember is: the average 7-year-old American girl only weighs 24 kg, so 12 kgf is a lot. It's probably about like climbing stairs, which, if you've ever climbed a lot of stairs, you know is very tiring. What really killed OLPC's human-power initiative was this realization: that a bunch of healthy well-fed young adult first-world men do not have a good sense for how much power a Rwandan child can comfortably generate. (At age 13, or 16, the story is very different.) Nonetheless, I think this project is tremendously important. I recommend that you consider designs like http://www.mattshaver.com/bikegen/index.htm, especially if bicycles are readily available in your area. This approach uses the rear wheel of the bicycle as a friction gear to spin the driveshaft at the very high RPM typically required by generators. Software improvements have been steadily decreasing the effective power draw of the XO, and I expect that these improvements will continue, making alternative power sources more and more effective. - --Ben -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkluH1sACgkQUJT6e6HFtqTK9wCfcbgPKi4jFHr+PVKBs12h8+Ug aqUAoIVMh/1c93KDXsB63U8+01s7jXfV =TUS6 -----END PGP SIGNATURE----- _______________________________________________ Olpc-open mailing list [email protected] http://lists.laptop.org/listinfo/olpc-open
