ECJ EUROPEAN Cleaning Journal

For many of us the thought of touching a door handle in a public washroom is not very appealing. The latest solution to tackling the germs left behind comes from two teenagers from Hong Kong who have come up with a cheap way to make a door handle that disinfects itself automatically.

Sum Ming ('Simon') Wong, 17, and Kin Pong ('Michael') Li, 18, presented the design of their door handle at the Intel International Science and Engineering Fair recently.

The door handle is coated with titanium dioxide, a mineral that kills bacteria and is found in paint and sunscreen. That takes care of preventing bacteria from growing on the surface of the handle, but because titanium dioxide is best at killing bacteria under ultraviolet (UV) light Wong and Li figured out a way for every bit of their bacteria-fighting handle to get some UV rays. They lit it from inside.

The handle itself is a cylinder of clear glass, with a strong light-emitting diode (LED) on one end that shines UV light through the length of the handle. Lit up with UV light, the titanium dioxide can go to work killing bacteria.

To keep the light on, Wong and Li attached a gearbox to the door that converts the motion of the gears from opening and closing the door into electrical power. That powers the LED, so it doesn't need an outside energy source to work.

The two inventors estimate the system would cost around $13 to build.