EMERGENCY ALERT SYSTEM FOR AUTOMOBILES
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-May-01
Car manufacturers today, particularly of luxury cars, are boasting in advertising of how well their cars insulate passengers from the ever increasing "noise pollution" particularly in large cities. The downside of this is that this also helps shut out the conventional alert signals, such as sirens and rail- road track bells, used to notify a motorist of emer- gency or possibly dangerous situations. It would be advantageous to move these signals "inside" the auto- mobile to avoid the motorist missing these signals, which could be achieved through RF transmission. DESCRIPTION Emergency vehicles, railroad crossings and other appropriate locations would be installed with low power transmitters and civilian automobiles with low cost receivers, both tuned to an emergency fre- quency, The receiver would be wired to override the car stereo, or perhaps be a part ofthe car stereo, and possibly include an LED or other visual alerting device. The potential danger in such a system is the ability of pranksters to override car stereos and annoy motorists. This can be made extremely difftcult at a minimal cost with the use of digital communica- tions. The transmitted signal would include a predetined code (which could be extremely long because the information content in the rest of the data transmitted can be very small), that would have to be decoded correctly before the alert signal inside the civilian automobile would be activated. Figure 1 shows a block diagram of the system to illustrate the simplicity, and potential for very low cost imple- mentation. The microcontroller required for this application could be extremely cheap because the only major computation that is required is for the detection of the transmitted code; and the modula- tion and demodulation could be achieved using a single chip similar to the Motorola ZIP/SYN which is already very alfordable.