<p>When a car owner want to lock or unlock his or her car today, it’s preferable done by using a</p><p>remote control. The system is really comfortable when the car owner is using the remote.</p><p>A problem arises if a thief gets the remote.</p><p>The thief doesn’t have to know where the car is parked, an approximate estimation where the</p><p>car is parked is enough.</p><p>For instance, it’s enough to know which car park the car is parked in. If the thief knows that,</p><p>he/she can repeatedly activate the remote control while looking for a car indicating with lights</p><p>and sounds.</p><p>Because of the fact that a car usually indicates that it has been unlocked by making a short</p><p>sound indication, there will be no problem finding the car.</p><p>The purpose with this project is to make a prototype which makes it harder for a thief to find</p><p>the car. A prototype will demonstrate a possible and alternative solution to today’s system.</p><p>To activate the remote control, the user has to press and release a button several times.</p><p>Each time the button is pressed a timer will start.</p><p>The timer will stop when the button is released. When the system has detected that the button</p><p>has been pressed three times, the data with the timer values will be encrypted with the</p><p>encryption algorithm TEA. The data will then be sent to the receiver unit. The received data</p><p>will be decrypted and compared to pre saved values to see if the data agree.</p><p>To be informed of the available system for user identification, a research was made. After</p><p>some investigation of different kind of biometrics, the conclusion was made to use just a</p><p>button instead of biometrics. Since there was no similar systems to the system I planned to</p><p>create, it was fun to create something that hasn’t been used in traditional remote controls.</p><p>The whole project is concentrated around two microcontrolers, one send module and a</p><p>receiver module for radio communications with 433 MHz on AM.</p><p>The microcontrolers are programmed with assembler by using the toolset MPLAB.</p><p>The ability to be able to control who should be able to read a message has been a wish for a</p><p>long time. That led to different kind of encryption/decryption algorithms. Earlier version of</p><p>the encryption algorithms simply replaced a character with another to diffuse unwanted</p><p>readers. With time, the algorithms have become more advanced. Today, text can be</p><p>encrypted by repeating same changes to a text to make it differ as much from the original text</p><p>as possible.</p>

When a car owner want to lock or unlock his or her car today, it’s preferable done by using a remote 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 the car 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 lights and sounds. Because of the fact that a car usually indicates that it has been unlocked by making a short sound 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 find the 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 button has been pressed three times, the data with the timer values will be encrypted with the encryption algorithm TEA. The data will then be sent to the receiver unit. The received data will 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. After some investigation of different kind of biometrics, the conclusion was made to use just a button instead of biometrics. Since there was no similar systems to the system I planned to create, 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 a receiver 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 a long time. That led to different kind of encryption/decryption algorithms. Earlier version of the encryption algorithms simply replaced a character with another to diffuse unwanted readers. With time, the algorithms have become more advanced. Today, text can be encrypted by repeating same changes to a text to make it differ as much from the original text as possible.

Att utforma interaktiva TV-tjänster skiljer sig på flera sätt från att designa för webb eller för vanliga PC-tillämpningar. Faktorer som lägre bildupplösning, längre avstånd mellan användare och skärm, och inte minst användandet av fjärrkontroll istället för tangentbord och mus gör att villkoren ser annorlunda ut än för PC-tillämpningar. I detta arbete beskrivs hur en videobutik för en set-top-box för digital-TV utformas via iterativ hifi-prototypning och utvärdering. Lärdomarna är tillämpbara på andra interaktiva TV-tillämpningar. / Designing interactive TV applications is in many ways different than designing for the web for for PC applications. Lower screen resolution, longer distance between user and screen, and not least the use of a remote control as input device instead of keyboard and mouse make for different conditions than when designing PC applications. In this thesis the design of a video store for a digital TV set-top-box is being outlined. The design is made through interative hifi-prototyping and evaluation. The learnings from this work are applicable on other interactive TV-applications.