Dear All, We tried to create a sewing machine based trial to power an XO - we geared it at about 90:1 so that the two dynamos should spin at about the same speeed as they would on a bike.
When connecting the bike light it does light - a little dimmer than normal - but the digital voltmeter for some reason when just starting slowly to spin the wheel by hand registers 0.1V or so when it's going smoothly at full speed it registers absolutely nothing. I tested measuring a few batteries and it seemed fine. I notice that on instructibles for the bicycle generator it mentions using a car alternator - I thought is a bit too much... http://www.instructables.com/id/Bicyle-Power-for-Your-Television,-Laptop,-or-Cell-/?download=pdf So we found two dynamos that can be purchased for less than $1 in the local market each one claiming 5.5W. I am not sure if it is that the rpms aren't suitable for the dynamo, or perhaps the speed varies too much... We want to go with foot power as it's not distracting, not obtrusive, can work indoors and out and during the night so that the learning for the child and family can continue all hours... I was also thinking about using one of the OLPC hand cranks and connecting it to a foot powered pedal or something like that... Would very much welcome anyone who might be able to explain what we saw and hope that we can find the way to harness the energy that is definitely there. I also saw http://news.bbc.co.uk/2/hi/technology/7796215.stm re. a gym and they get 100W from an exercise bike machine... 10W would be enough for us I reckon... Thanks/Regards, -Mike (Working in Kabul to support OLPC Afghanistan) _______________________________________________ Olpc-open mailing list [email protected] http://lists.laptop.org/listinfo/olpc-open
