Don't try this one at home ... yet.
(Credit: Bare Conductive)
A non-toxic paint, which can be applied to almost any surface, conducts electricity for creative projects.
However, a product created by students at the London Royal College of Art in 2011 is making conductive paint much more accessible. Bare Paint can be painted onto almost any surface, making it perfect for fun, creative projects — and teaching kids about circuitry. Drying at room temperature and with a surface resistivity of approximately 55 ohms/square at a 50-micron layer thickness, it can be used to power low-energy electronics, such as small speakers and LEDs.
"We generally split applications into two simple classifications: signalling and powering," said Bare Conductive on its website. "Signalling could include using the paint as a potentiometer while interfacing with a micro-controller, as a conduit in a larger circuit or as a capacitive sensor. Powering a device would include lighting LEDs or driving small speakers. The most interesting stuff happens when you combine these properties into something new."
The paint itself is water soluble, so it can wash off easily. For more permanent projects, it can be painted over with a waterproof varnish, or other paints. It can also be applied to a wide range of surfaces, including paper, wood, metal, fabric, plastics and some rubbers — although not skin, as it hasn't been approved for topical application. The team seems to be working on a body paint version, however.
The team has a bunch of project tutorials available on its website if you're just starting out and looking for ideas, and the products are available in both pens and paint pots, starting at £6.00 (around AU$9.50) for a single pen, with free shipping worldwide.