The electromagnetic spectrum contains many kinds of rays that the human eye can’t see. In fact, we really only see a very small portion of the spectrum — from roughly 380 nanometers to 740 nanometers. The electromagnetic spectrum extends far beyond that to gamma rays at one end and radio waves at the other end. UV light is just outside of the visible spectrum, from 100nm to 380nm. That includes four types of light: vacuum UV (which only propagates in a vacuum), UVC, UVB, and UVA. We’re constantly exposed to UVA and UVB light from the sun, but we’re protected from UVC by the ozone layer. That’s a good thing, because it would kill us. It also kills coronavirus, which is why you might want to build this handheld UV sterilization device.
A disclaimer is necessary here, because UVC light is very dangerous. Be sure that you’re wearing the appropriate protective equipment and never expose yourself or anything living to UVC light. You just want to expose surfaces to UVC light in order to kill coronavirus. UVC damages genetic material (DNA, RNA, and proteins), which halts cell reproduction. So you could, for instance, use this device to completely disinfect your smartphone screen or your door knobs. No residual radiation remains after the light is turned off, so the unit is only potentially dangerous when you’re actually using it.
To build this device, called UVClean, you’ll need a GTL-3 UVC bulb, an E17 bulb socket, a power supply, a boost converter, an Arduino Nano, a rotary encoder, an OLED screen, and a handful of common electronic components. You will also need a 3D printer to fabricate the enclosure. The UVC bulb receives power from the power supply, but only when the Arduino Nano tells it to. That is protected by a four digit passcode, which is why you need the OLED screen and rotary encoder. The passcode will ensure curious children (and adults) can’t turn it on and unknowingly harm themselves. If you want a convenient way to disinfect surfaces, UVClean could be worth making.
If you have ideas of your own on how to combat the spread of coronavirus, be sure to check out the COVID-19 Detect & Protect Challenge that we’re currently running with the UNDP, UNICEF, and several other top technology partners.