The password based security system consists of two sections: The user interface section and the execution section. The user interface section consists of a matrix keypad and an LCD display. The execution section consists of an 8051 microcontroller and a relay. This system is meant to provide door security where only privileged members can enter. The system has a five digit password which is stored inside the microcontroller and it is given to the user. The user can enter the password through a 4×4 matrix keypad and this information is temporarily stored in the microcontroller. The system then compares it with the original password and grants access if the password is right. The door is opened by turning on a relay mounted in the pcb and turns off after certain fixed time. If the password is wrong then the system gives two more chances to the user and if it all goes wrong an alert is given. Necessary instruction are displayed on an LCD module.