This system involves design and construction of security system controlled through PC with several sensors and a controller attached in order to perform its specified tasks. In this project we can detect illegal person, who want to enter in house or industries. After detection automatically hooter (buzzer) , halogen lights will be turn on. The number of nearest police station will be dialed. The movement of that person in particular area can be captured using CCTV mounted on stepper motor. It is basically combination of sensors namely; IR sensor, LDR sensor, Magnetic sensor, Pressure sensor, Wire sensor giving input to the microcontroller. All the sensors are connected in parallel to the microcontroller so that we can add any new sensor easily. For this we used latest and most advanced 20pin microcontroller IC 89c2051 from MCS51 family