Food delivery services have become essential businesses during the global pandemic.
The containers for food delivery are sometimes the only point of contact people may have with the outside world during a lock-down. They also come into contact with essential workers who are most exposed to the risk of infection.
Corona is a respiratory virus, and therefore not infectious through food-borne consumption, but can be inhaled from residue left on packaging after handling. Therefore, finding a way to disinfect the food delivery packaging virtually eliminates the risk to customers who order food delivery from a service like Foodora.
We use this solution already in our apartment to disinfect masks, which is where we drew our inspiration from.
What it does
Our add-on product to food delivery boxes used safe, environmentally friendly UV-C light as a germicidal and viracidal food delivery packaging disinfectant. UV-C light kills viruses by scrambling their DNA and RNA, making them incapable of reproducing.
It only takes 10-15 minutes to be effective, which Uber Eats lists as their average time for deliveries, making it a perfect solution for drivers to simply place the food packaging in their delivery box, turn on the UV-C light, and then turn it off when they arrive for their delivery.
The effective range of UV-C light is 2 meters. The cost is only $25 per bulb. The bulbs last for 1000's of hours. These could be easily and cheaply installed in existing semi-rigid food delivery packaging.
How I built it
We initially built the proof of concept to sanitize disposable masks following positive test results from 3M (page 6).
It's a really straightforward build which only requires a shoebox, aluminium foil and staples, as well as the UV-C compact fluorescent light and a screwable lightbulb socket (E27 standard).
We simply put the mask on top of a transparent plastic container inside the box, close it and flip the switch. Then after 15 minutes we turn it off and get back our toasty clean mask. According to 3M, the medium heating from the CFL lamp also contribute to the sanitizing process.
For the final product, we plan on making an additional lightweight, 3D printed, adjustable structure to keep the bag from deforming and to help mount the lightbulb onto. We could also explore the potential of UV-C light emitting diodes, which could save up the battery and extend the apparatus' lifespan.
Challenges I ran into
It was hard finding a powerful lamp fitting an E27 screw simply off Amazon, since most UV-C lamps for the general public are usually sold for aquarium algea removal and have a weird socket. Also they're usually not as powerful.
Another hurdle was how to make this safe. UV-C can severly damage the retina and give skin cancer (just like any UV light), so we bought some biological hazard stickers off Amazon and put some on the lightbulbs and a big one on the box, so that people wouldn't find this lamp and use it for decoration (as it emits a beautiful blue light).
Accomplishments that I'm proud of
We also tried making a limit switch based system to automatically turn the light on and off when closing/openning the box, and a timeout to shut it down after 15 minutes but we had trouble with my high voltage relay board and had to resort to a manual trigger instead.
However we have an Arduino code ready to make that switch work.
You can find it here on GitHub.
What I learned
Don't nail electronic components to the wall...
What's next for Sanitizer
Building it for a food delivery company