Our wearable device packages a microdroplet sensor in a user-friendly wristband that alerts users when they are not practicing proper social distancing techniques. Instantaneous air sampling and virus identification is exceedingly difficult and hard to make accessible for a wider demographic. Instead, our sensor detects the presence of local droplets to inform users of their risk level for contracting an airborne disease. If the sensor detects high concentrations of droplets, the user is in a high risk environment. If the sensor detects low concentrations (the base case), the user is in a low risk environment. Our technology hopes to reduce the unpreparedness and fear of walking into spaces of unknown contagiousness.
Our sensor specifically targets the detection of microdroplets, particles that usually cannot be seen by the naked eye. The size of these droplets make them dangerous for three reasons:
The risk of inhaling these droplets is higher in indoor spaces because air flow is limited. Our solution was inspired by similar challenges experienced by the International Space Station. The ISS is a closed-loop system where ambient air quality monitoring is essential to the health and well-being of our astronauts. Consistent air monitoring allows them to reduce the occurrences of illness in a confined space. Similarly, we would like to reduce the occurrences of infectious disease by providing consistent indoor air monitoring for all.
After seeing the health and economic fallout due to COVID-19 and considering the possibility of a second wave later this year, we were inspired to take a swing at the challenging problem of designing a wearable real time sensor that could possible tell an individual when they’ve walked into a room with a dangerous density of microdroplets in the air. Not all droplets contain coronavirus but the working hypothesis of the CDC is that virus containing droplets emitted by an infected person and inhaled by a second person has been the leading cause of the spread of COVID-19.
Our basic approach with the design consists of an array of electrodes of suitable geometry to capture microdroplets with diameters in the range of 100nm to 10m based on data from NIH and NASA. We considered the use of our device indoors on Earth and in the ISS.
We found it challenging to consider the detailed physics regarding the interaction of droplets with the sensor at the microscopic scale, especially in consideration of what we think will be a high degree of sensitivity required for successful functioning of the sensor. We further validated our ideas by creating a 3D model of them using Solidworks. We also went through an EXTREME amount of trial and error in our quest to demonstrate a prototype. But it was good times!
[1] ‘COVID-19 United States Cases by County’, Johns Hopkins University https://coronavirus.jhu.edu/us-map
[2] ‘ISS Ambient Air Quality: Updated Inventory on Known Aerosol Sources’ M. Meyer, NASA Glenn Research Center 2014
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150000882.pdf
[3] ‘Generation and Behavior of Airborne Particles (Aerosols)’ P. Baron, National Institute for Occupational Safety and Health Centers for Disease Control and Prevention
https://www.cdc.gov/niosh/topics/aerosols/pdfs/Aerosol_101.pdf
[4] ‘The Size and Concentration of Droplets Generated by Coughing in Human Subjects’ S. Yang et al. 2007
[5] ‘Quantity and Size Distribution of Cough-Generated Aerosol Particles Produced by Influenza Patients During and After Illness’ W. Lindsey et al. 2012