In the past few years, we have covered a whole host of emergency chargers that let you generate electricity for your gadgets in case of a power outage. The miniO thermoelectric charger serves as a 5W USB charger for your smartphone. It generates electricity using the temperature difference between the thermoelements.
The entire kit weighs only 350g. It measures 10 x 4cm, so you can take it with you anywhere.[where to get it]