Although today’s smartphones come equipped with large touch screens, Bluetooth, build in GPS receivers, multiple connectivity options and all other useful capabilities they are very energy consuming devices and have pretty disappointing battery life. This could be a big problem while traveling in remote countries with scarce infrastructure or in times of big catastrophic events when the entire infrastructure fails and with it the basic services such as electricity supply. But a small hand-powered charger in your pocket can make a difference providing you’ll never have to live with a dead phone again.
Ben Heckendorn discovered that a windup flashlight had enough juice to recharge his android smartphone. He made a quick DIY tutorial on how to convert a wind up LED flashlight to wind up smartphone battery charger by adding a simple voltage regulating circuit using a Zener diode and a 100hm resister. By adding a USB port to plug in a microUSB recharging cable the device is capable to charge all smartphone models using USB chargers.
Check out the video below to see how it’s done.
If you are not handy enough, or if you want to save yourself some troubles with assembling it on your own, you can also check the stores for chargers.