Toast Test Device Simulates COVID-19 Spread in Indoor Environments Using Toast Smoke

According to the CDC, the COVID-19 virus is spread via respiratory droplets that can hang in the air for an excessive amount of time, depending on the droplet size. Mitigating infection is done by wearing masks and maintaining a six-foot distance from those around us. That said, it’s rare for people to become infected with COVID-19 while flying. Still, there is a reason why infection rates don’t skyrocket in that tiny, enclosed space, as the air is circulated every three minutes, with most of the replacement air coming in from the outside. Since the air is circulated frequently, the infection rate drops as most respiratory droplets have been flushed.

The same can’t be said for places such as bars, restaurants, and even our homes, where infection rates are the highest. So how do you know how the virus would spread in those places? Easy, just burn some toast. That’s the idea behind Rabbitcreek’s Toast Tester – a device that uses toast particles to simulate COVID-19 respiratory droplets. The smoke particles from burnt toast are about the same size as the virus particle, about 2.5 microns or less, and the smoke cloud responds to the same HEPA filtration and ventilation efforts found in most public places. This means that toast smoke can be measured in nearly any building.

Rabbitcreek designed his Toast Tester around the ESP32 microcontroller and uses a PM2.5 particle sensor to test air quality. The device is outfitted with a rechargeable LiPo battery (700 mAh) and features an LED display data on the surrounding air quality. All the electronics are housed in a 3D-printed enclosure that sports a dog nose, used to draw air into the device. Several buttons on the Toast Tester include on/off, a button for uploading data, and a reset test/start button.

Rabbitcreek has uploaded a detailed walkthrough of his build on his Instructables page, complete with the necessary files and schematics to recreate the project.