This book gives you an overview of Designing and implementing a cost effective Automobile Theft Deterrent System (ATDS). The design talks about merging a ublox GPS unit and a Wavecom GSM module which can be of good support to design a fleet management system as well. The main feature of the ATDS is to deactivate the vehicle when the unit receives a specific command from the authenticated mobile unit. The deactivation technique is based on interrupting the ground connection to the Power Distribution Centre (PDC) by providing an activation message from the users mobile unit. Once the PDC is disconnected the Auto ShutDown Relay (ASD) is latched this in return kills the engine and the complete electronic Control units (ECUs) present in the vehicle. Further the vehicle is tracked through GPS. The GPS data is written to the company database and transferred to the GIS to provide the user with the location on the map. The design talks about interfacing a MEMS sensor for speed detection. This book focuses on the creation of an interactive ATDS. The ATDS is designed using OpenAT OS.