Singapore has sporadically been affected by haze caused by slash and burn practices in our neighbouring countries. Conventional practice is to don filtration marks - often of the N95 type in Singapore - when out in potentially hazardous environments. This inconvenience, along with the lack of general availability of masks, spurred us to ideate and design for an alternative solution to the problem of air filtration.
What it does
We use an air curtain to create a positive pressure gradient between the user's nose to the exterior of the design. Air curtains use streams of high-velocity air to divert ambient air away from the user - common current uses include fume hoods in chemistry labs and differentiated air zones in shopping malls. Implemented alongside the air curtain is a smoke detector which provides information to the user regarding the current detected PM2.5 levels. The user can activate the ventilation functions wirelessly or via an innocuous button built into the system.
How we built it
We used the cutting edge technology of a penknife, and sourced a centrifugal fan. The electronics are powered via two different battery packs of 12V and 3V, linking up to the fan, microcontroller, and user interfaces accordingly. The centrifugal fan was placed in front of the user's right chest, to reduce back-pressure as much as possible - attached to the centrifugal fan via a coupling is a 20mm polyurethane tube, curved to fit the shape of the user's head; couplings were 3D printed and laser-cut as required. https://gfycat.com/gifs/detail/OblongHandyAustrianpinscher
Challenges we ran into
Simulation and calculation of airflow was a significant challenge - accounting for both laminar and turbulent airflow led to many unexpected results during our prototyping phase. Sourcing of necessary parts also posed an issue - with varying types of fans (eg, centrifugal, axial, etc.), we had to carefully consider our requirements and finish a rough schematic/use case before making the necessary purchases. The routing of air was also an issue. We experimented with the number of vents, different angles of attack, and vent position, during the process of optimizing our result for our desired minimum viable product.
Accomplishments that we're proud of
Our prototype is functional, and effective according to our hypotheses. Our team was able to flexibly pivot our goals several times during the design process - in routing considerations, peripherals used, etc., and as a result we feel we have achieved the best outcome possible of all the existing parallel universes. We're also satisfied that our product tackles a problem that affects a very significant number of people - with a full fledged implementation having the potential to be used worldwide.
What we learned
We gained a basic understanding of complex fluid dynamics; the nature of turbulent vs laminar flow, and its effects on our prototype. We gained experience with Arduino wireless interfacing (via the ESP8266); and we were able to debug and fix any errors we faced along the way - debugging is always a learning experience!
What's next for Windshield
Further refinement of the air ducting system; better sizing of the fan, and a hoodie designed for fan implementation, would make the product very viable for commercialization.