The EnerJar – a DIY device that measures the power draw of electrical appliances, was announced as the winner of the Greener Gadgets design competition in February.

The competition gave designers across the world the challenge to create a greener gadget concept – a product that would address issues such as energy, health and toxicity, and new materials; with the winning design receiving a $2500 prize.

The EnerJar, designed by Matt Meshulam and Zach Dwiel from the US, was developed as a simple method for people to monitor, and then reduce, their energy use. The EnerJar simply plugs in between the gadget and the wall socket to give a usage reading, and unlike other similar devices, the EnerJar is not intended to be a commercial product; instead the design will be available for free on the web.

A primary design goal was to reduce the number of components, and to choose components that can be easily sourced. This makes construction easier for others who build the meter, while also minimizing the environmental footprint. The power supply, for instance, is salvaged from an unused cell phone charger, and the gadget enclosure, as the name suggests, is a glass jar.

Other notable entries in the competition included a self powered twist camera that uses a winding mechanism for power and would be capable of taking several photographs per twist of the mechanism; and an innovative powerstrip named the EjectPowerstrip. This innovative device adds small foot pedals to the traditional power strip. Stepping on a foot pedal forces the plug's prongs up and outward, which would unplug electronics not in use in a simple and quick way, and would be a far more child-friendly option than leaving cords lying around.

While most of the designs in the competition are just concept products, the technology exists that several of them could realistically be developed into commercial products – although some concepts, such as the ‘tattoo electronic interface’ – a cell phone printed onto the skin, may only become a reality in science fiction movies.