Our very own library, Geisel, is always occupied by many students; but we can never know exactly how packed it is until we are physically inside searching for seats. This is very troublesome because the library is located quite far from most students' rooms, which brings them to walk long distances just to realize there are no available seats. We thus wanted to design something that can provide a real time representation of the population in the library that can be accessed elsewhere.
What it does
Our project counts the number of people that passes through a set of sensors and classifies them as entering or exiting based on their direction of travel. This data is then passed to an excel spreadsheet, which will plot the approximate number of people in the library over real time.
How we built it
We placed three ultrasonic sensors in a row, which are separated by the distance of approximately one meter. These sensors are connected back to the Arduino and then into a laptop to plot of the graph.
Challenges we ran into
The speed of emission for the ultrasonic sensors were very fast. This caused problems as it sometimes records a person to be at multiple positions at the same time, which then messes with our algorithm to define the person's direction. Another issue was that if a person changes direction between the two out-most sensors (which should not affect overall population), the Arduino counts the loss/gain of one unit of population.
Accomplishments that we're proud of
We are proud of creating an arrangement of sensors that could record data with nearly no delay. This gives us highly accurate measurements because data is collected every 40 microseconds.
What we learned
Although it may seem easy to count the number of "things" passing through a point, it is actually very difficult to determine its direction due to the high emission rate of the ultrasonic sensor.
What's next for Count On Me
We hope to see Count On Me implemented in most public study areas on campus and deliver a real time graph online for students to see where it is most convenient for them at that time.