Entry System with Keyless Stealth Feature

Overview

The stealth keyless entry system is based on the AT90S2313 microcontroller which provide strong solution to a common security problem.

Explanation

There are 10-button keyless entry pads that are typically installed in this system. This can be risky over time since they are being controlled by numerical entry codes. The entry code can be easily determined by knowing which keys are pressed. This is due to the dirt from fingers deposited on keypad coupled with the natural wearing  of the dye on the keypad.

A hidden entry system if performed by a modified doorbell which rings when pressed normally. The doorbell will not ring when the entry (Morse) code is entered making the garage door unlocked. The code is deciphered by the MCU and compares it to the master code in EEPROM before sending the command to open the door.

The user is provided with options by the system that can be used to practice its operation. These options, when a dumb terminal is connected to the RS232 output of the system, allow the user to print the doorbell button closure times, print the Morse code characters, and print out the master code.