Sterilev is an automatic self-disinfecting door handle for use in public restrooms, in particular hospitals. The cleaning element is a UV-C bulb which is 99.99% effective against bacteria and viruses. On each closure, the door passes a magnetic field initiating a timed cleaning process. Once the time has passed, the circuit will cut out and the handle will be clean and ready for the next user. The device is retrofittable to current doors with mounting pins at pre-existing holes.
My inspiration came from the continued outbreaks of Healthcare-Associated infections throughout Irish hospitals. Research shows that hands are the primary transmission route for such infections, with Norovirus having the ability to transmit onto seven consecutive surfaces once present on hands. During observation, I found that only 76% of users actually washed hands after using public restroom facilities, of these approx. 30% used soap. On taking samples of touched surfaces, some contained 10 million bacteria/cm2, with a number showing over 1,000 fecal particlas/cm2. I studied the benifits of UV-C light in disinfecting surfaces. A single bulb can last up to 2 years and does not leave residue or contain any chemicals. In addition, bacteria can not mutate to become immune to the light as has become characteristic of many chemical cleaners.
I began by studying the benifits of UV-C disinfection over other existing methods. Using skecth models I found the best shape which would reduce the amount of contact on outer surface. I designed a timer circuit which would initiate the bulb for a period of 7 - 10 seconds. An LED indicator would show the next user that cleaning was in progress. Hands entering the cleaning area will be detected by the PIR sensor and will cut out the power to the bulb. Over exposure to UV-C light can be dangerous to skin and eyes hence these safety measures were taken. 1 billion E Coli/cm2 were applied to the handle under laboratory conditions. After 10 seconds, there was only 10 E Coli/cm2 left present. The handle was a huge success in testing. Its simple plastic shell houses a relatively simple circuit and bulb. There are no moving parts and the rechargeable battery can easily be removed for charging by staff.