If you own any gadgets at all (and if you read Futurismic, I expect you probably do), you’ve probably suffered the ‘black screen of doom’ at least once, when your battery dies on you, leaving you stranded in a hi-tech world with a metaphorical limb missing. The good news is that scientists are looking at new ways to harvest energy for your tools while you’re on the move – using solar power, heat or motion to charge your batteries.