Potential Sensors (FINAL): Gem Pressure Switch


A typical way to count cars that pass by is used in every city and highway by a company called W-Trans. The basic use is to measure how much traffic flow there is in a certain area. They go about counting by laying down two rubber tubes in parallel and both perpendicular to the road. These tubes are attached to counting equipment at one end and closed at the other. These tubes use sensors called air switches. The air switch is triggered when a car rolls over the tube. The air in the tube compresses and then pushes towards the nearest exit which would be the air switch.  Two tubes are used to determine from which direction the vehicle is coming from. The road tubes come in different sizes including a Half Round design for 80 mph and up, Standard Round Tube for around 50-60 mph, and lastly the precision mini tube for residential areas. The latter is the tube for us since we will be dealing with cars entering parking lots at about 10 mph. The sensor is the pressure switch which will turn from low to high or vise versa depending on the psi level that we set. When a car rolls over the tube the pressure will raise the psi within the tube to the adjusted level and count up or down depending on if a car enters or exits the parking lot.  Prime Parking’s pressure sensors in particular are from the company known as GEM.  The PSI range these sensors can be calibrated to range from 15 PSI – 60 PSI

Programs Used

MPIDE is our main programming tool that will be used to get Prime Parking up and running.  MPIDE supports a number of languages, including C++ and Java.  Giving out information through a web server as well as collecting sensor data, MPIDE is the best choice for us to implement data access through a web server.


Potential Sensor for Prime Parking


We are thinking about using a Precision Cut Tube as our contact for the car instead of an Ultrasonic Distance Sensor.  When something goes over this contact, air will be pushed towards the ends of the tube, in which we will be implementing some pressure switch at the ends.  This will be our way to trigger the count of cars to go to Prime Parking.  Many cities already implement this type of device to keep track of cars along the road, so this seems to be the best approach for our project to be successful.

Prime Parking: The Problem & Objective

Parking has always been major problem for college students whether they go to a University or a Junior college.  Many campuses have limited amount of space for students to park at during certain times and this causes them to be late for their classes.  Although there are some colleges where a parking garage can monitor how many parking spaces are available, others are not so lucky.  In particular, Sonoma State has no way to track how many parking spots are available throughout the day.  This combined with the small amount of parking spaces available causes students to not have an idea of how many spots are available, thus wasting their time looking around for parking.  Having a convenient way to not only give students an accessible way to monitor how many spaces are open at the parking lot but also to view these spots through their mobile device will allow finding parking that much easier.

Our project aims at solving the problem that many college students have of trying to figure out how many parking spots are available on campus.  At the end of two road tubes, pressure sensors will be attached on the end of each tube.  Cars going over the road tube will trigger these sensors to send data to a specific microcontroller.  In our case, these two sensors will be connected to a PIC32 Microcontroller, aimed at storing the information collected from the sensors.  The main goal of Prime Parking is for users to access information on specific lots easily before arriving on a given lot.  This is made through the PIC32’s main application; collecting the data from the sensors and pushing that information onto a web server.  With this idea in mind, students will have the power to track the number of parking spaces available by accessing their web browser on the following devices: smartphone, tablet, or computer.  Rather than displaying the number of spots at the entrance of the parking lot, students have the knowledge to plan accordingly when heading to campus and to know exactly which parking lot they need to go to.