AUTOMATED PARKING LOT SYSTEM - Data Transmission Subgroup
John Paul I. Catalan
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My contribution here is the planning part of the project. I was responsible for planning the general framework of the data transmission system and the area-mapping scheme used in the project. I also planned out, with the help of our mentor, what specific electronic components to use. My partner, Paul Canlas, was in-charge of the implementation of the planned system.
Specifications
The subgroup's main objective was to interconnect the parking sensor and the central computer to be able to map out the entire parking lot. All signals from the sensors attached in each parking space are sent to our system for transmission. Our job is to collate all these signals and send these to the central computer for data and map layout processing.
There have been several important factors that were considered during the planning process. The system had to be very effective, in the sense that it can send data fast enough to make the mapping real time. Thus, car owners will be looking at the accurate display of the actual vacant slots in the parking area. Also, the system must be simple enough to be able to troubleshoot easily and to lower implementation costs. And lastly, the system must be scalable; meaning, it can be easily upgraded in case the system needs to be expanded (i.e. adding more parking spaces).
Discussion
There are several ways to handle the situation. Let us take figure 1 as our parking lot; it has 8 spaces. One instant solution of determining their status is by attaching the output wire of each parking space sensor to the computer input, figure 2. Status checking is executed in real time, since the status port of the computer instantly responds to every change that occurs in the status lines. The only problem with this set up is the fact that computer input lines are very limited. In fact they only have 5 input pins in the parallel port. In our case, three of the parking spaces will not be attached to any of the pins, thus, will not be monitored.
Another solution is by scanning the spaces sequentially, like the figure shown in figure 3. This solution is very scalable since serial reading has no limitations in the number of nodes it can read in sequence. The biggest problem, however, with this setup is its effectiveness in monitoring the parking lot. Obviously it cannot read in real time because the parking areas can only be updated after all spaces have been checked. This is a problem in areas with many parking spaces, since the map that the data will produce is almost useless because it does not accurately report the actual status of the entire parking lot system.
So what we decided was to implement an integrated version of the two schemes by dividing the area into parking sectors. The data from these sectors are inputted in a parallel fashion, while the spaces in each sector are read serially and fed to the output lines of the sector. In this manner, data is sent near real time while overcoming the problem of scalability. Figures 4 and 5 show an illustration of the proposed system.
Schematics and Description
FIGURES AND SCHEMATICS WILL BE FOLLOWED UP TOMORROW (10/2/2001)
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