16-05-2014, 11:13 AM
SOS TRANSMISSION - Through Cellular phones to save Accident Victims
SOS TRANSMISSION.doc (Size: 108.5 KB / Downloads: 13)
Abstract:
This paper describes an ORIGINAL IDEA to help cellular phone users caught in an accident. The idea has been developed keeping in mind the considerations of cost and compatibility with existing system. The Short Message Service or SMS as it is popularly referred to, is made use of for this purpose.
The solution offered is the Force-Transducer method. The victim is assumed to be unconscious and the accident is detected automatically. Detailed simulation results at a scaled down level are provided for this solution. The threshold level is set based on data collected from the experiments.
One major problem in such design is the technique to find the victim’s position. The Global Positioning System (GPS) is found to be costly. So, an unorthodox design using Radio Direction Finders (RDF) and beacon signals is described. The Goniometer or Crossed Loop Antenna is used for this purpose. This reduces cost effectively when compared with the GPS system.
Introduction:
Cellular phones are turning out to be a menace on the road. This is a major problem for the cellular phone manufacturers. This paper provides a solution which transmits a SOS signal to save the accident victim. It describes in detail a cost-effective foolproof solution.
There are many factors to be considered when designing such a system. In most of the accidents, the victim becomes unconscious. How is a SOS transmitted then? Here, many ideas can be implemented. One such solution is described here. The cell phone is fitted with a transducer, which detects shocks. The cell phone automatically transmits the SOS if the shock level goes beyond a certain percentage.
The Toy Car Experiment:
In case the victim becomes unconscious, the system must be able to automatically detect an accident and transmit the SOS automatically. In order to achieve this, a shock transducer is used to measure the jerk experienced through the accident and trigger the SOS circuit if the force level is very high. This system needs statistical data acquisition to find out the exact threshold level of the force in an accident. It is highly expensive to simulate the accident in real time. So, a scaled down experiment is used. Here, a pair of toy cars of mass 200g is made to collide with each other. The force caused by them is measured by simple piezoelectric transducers. The results of this experiment are tabulated below.
Identifying the Position of the Victim:
The problem of knowing where we are has been an interesting and difficult problem through the ages. Years of research have resulted in the Global Positioning System (GPS). This technique uses three satellites and pin points the location by the triangulation process, wherein the user’s position is located as the point of intersection of the three circles corresponding to the satellites. Installing such a system is quite simple. But the major constraint here is the cost. A normal hand-held GPS costs around $100 and weighs quite heavy. Minimizing the above apparatus will increase the cost further. This would mean an extra cost of Rs.10000 to Rs.15000 for the Indian user.
Simulation:
The simulation of this system has been carried out in a small scale level. As seen from the block diagram a microphone substitutes for the shock transducer in the original system. This then transmitted through a Medium Wave transmitter to a personal computer. The signal received is passed through an ADC and received in a C program. This program checks the signal value and sets a flag variable when it goes beyond a certain level. This flag is continually checked by a thread of the JAVA front-end. If the flag is set, the program connects to the back-end database and displays a list of users to whom the mock message is sent based on the hierarchy explained above. The simulation does not cover the positioning part of the system as that is too expensive to be done on small scale. The screen shot of the Java front-end is shown in the next section.
CONCLUSION:
The system though complete presents a few limitations. They are, the system requires the user to place the cellular phone in a stand or connect the transducer to the vehicle in case of four wheelers. Though this might seem as if taking choice from the user, the fact that the system deals with a question of life or death is more important. The system needs detailed surveying to decode the position of the user in polar coordinates to actual localities. This however is a one time job. The system does not handle multiple victims simultaneously. However, priority can be allocated to users based on the force measured. False alarms are bound to occur in such a system.