Car Lock Improved by Configurable Key
When a car owner want to lock or unlock his or her car today, it?s preferable done by using aremote control. The system is really comfortable when the car owner is using the remote.A problem arises if a thief gets the remote.The thief doesn?t have to know where the car is parked, an approximate estimation where thecar is parked is enough.For instance, it?s enough to know which car park the car is parked in. If the thief knows that,he/she can repeatedly activate the remote control while looking for a car indicating with lightsand sounds.Because of the fact that a car usually indicates that it has been unlocked by making a shortsound indication, there will be no problem finding the car.The purpose with this project is to make a prototype which makes it harder for a thief to findthe car. A prototype will demonstrate a possible and alternative solution to today?s system.To activate the remote control, the user has to press and release a button several times.Each time the button is pressed a timer will start.The timer will stop when the button is released. When the system has detected that the buttonhas been pressed three times, the data with the timer values will be encrypted with theencryption algorithm TEA. The data will then be sent to the receiver unit. The received datawill be decrypted and compared to pre saved values to see if the data agree.To be informed of the available system for user identification, a research was made. Aftersome investigation of different kind of biometrics, the conclusion was made to use just abutton instead of biometrics. Since there was no similar systems to the system I planned tocreate, it was fun to create something that hasn?t been used in traditional remote controls.The whole project is concentrated around two microcontrolers, one send module and areceiver module for radio communications with 433 MHz on AM.The microcontrolers are programmed with assembler by using the toolset MPLAB.The ability to be able to control who should be able to read a message has been a wish for along time. That led to different kind of encryption/decryption algorithms. Earlier version ofthe encryption algorithms simply replaced a character with another to diffuse unwantedreaders. With time, the algorithms have become more advanced. Today, text can beencrypted by repeating same changes to a text to make it differ as much from the original textas possible.