I'd probably just cannabalize an existing generator made for this purpose. There's a ton of them out there that you can find by googling the title of the thread.
And though I've never used it to charge a cell phone, I think my hand crank radio/flashlight can also charge a cell phone. Not sure, though. It's this one: http://www.ecrater.com/product.php?pid=4234703
While you're building green chargers, or whatever you wanna call them, you could build one out of solar panels, or copy the shake and charge flashlights, or if you've a little Ham Radio operator in you, build your own WiFi charger, which I'd bet could be modified to work with any cordless phones and possibly lower power waves with the correct crystals. I doubt that AM/FM bands would provide enough power, but then again any 'free' energy is energy, so its a possibility. piezo-electric (sp?) components are moving forward again, so if you were really inclined you could theoretically extended battery life by including some components inside of the phone. Probably not enough to recharge the battery, but more than likely enough to extend the battery life. Anytime I'm leaning back in my work chair and thinking about where I can grab some 'free' (I just mean no power company included. or batteries purchased.) energy. Basically if there is ANY change in ANYTHING, there is a theoretically sound method for creating or thieving energy from it. Most cells charge on .5 - 2.0 amps at 5 volts. I think. Correct me if I'm wrong someone.
Eton also makes the Solarlink FR-600. AM, FM, SW, NOAA bands, light, siren, phone charger. You can use batteries, or charge the internal batteries with the built-in solar cells or dynamo.
i need to design some hand-cranked charger for my project...do have any idea that can help me?
i mean what web can i study to understand the principle..