In a hall of the Africa Innovation Summit in Cape Verde, the smell of melting plastic permeated the air. A crowd had gathered around a small stand to watch a special kind of machine go to work.

Controlling the device were members of WoeLab, a community “maker space” based in Togo, West Africa. Over the space of an hour, their creation gradually built a small plastic toy, layer by layer. It looked and performed like a typical 3D printer – but this one was different. Why? It was made almost entirely from electronic waste and scraps.

The demonstration in Cape Verde clearly impressed the audience – the Woelab team won the award for “best innovation” of the exhibition.

Electronic waste, or e-waste, is a rapidly growing global problem. As our desire for personal gadgets grows, we end up with more and more electronics in incinerators or landfills, potentially seeping toxic substances like lead and mercury into groundwater.

Yet many are realising that the gadgets we chuck away can be ripped apart and transformed into something new – brand new technology, or even art. Your old phone, printer or electric toothbrush may seem worthless, but to these MacGyver-style makers, it’s a building material.

In 2012, we discarded 48.9 million tonnes of electrical and electronic products. If current trends continue, by 2017, the annual amount of e-waste produced globally will reach 65.4 million tonnes – that’s roughly 20% of the weight of all the people living on Earth.

“The e-waste issue has exploded, and will continue to explode because of increased production of electronic equipment – anything with a battery or a plug – and because of the enormous hunger of consumption of this equipment around the world”, says Ruediger Kuehr,executive secretary of the Step Initiative, a United Nations University programme aiming to tackle e-waste.

Step recently produced the first “e-waste world-map”, showing how much e-waste each country produces. At 11.1 million tonnes, China was the leading producer in 2012, followed by the US at 10 million tonnes.