Power Hog only lets power flow to toys when children put money into the piggy bank. To see more designs for green gadgets click the link in the main text, left (Image: Greener Gadgets)

Design magazine Core77 and the Greener Gadgets conference organised a competition to showcase innovative new devices designed to improve the energy efficiency of electronic gadgets.

The shortlisted designs include a solar powered venetian blind that doubles as a lamp and devices to deal with “energy vampires” – gadgets that continue to sap power when they are in standby mode.

See a gallery of selected shortlisted designs