Circuit Lake

Electronic Project and Circuit Collection

Secret Keyless Entry System

01/08/2010 Category: AVR, Microcontroller, Project, Security System


This AVR AT90S2313 based project modifies a home’s existing doorbell to become a hidden keyless entry system. The doorbell will operate normally unless a secret code is entered via the doorbell button. When the secret code is entered, the doorbell does not ring and the garage door is opened.

An Atmel Microcontroller AVR AT90S2313 is used to decipher the entered code, compare it with a master code stored in EEPROM, and control opening the garage door when the entered code matches the master. When pushing the doorbell button, the doorbell will be rung as soon as there is a deviation from the master code. This will essentially be immediately to anyone not aware that the doorbell button doubles as a keyless entry system.

The stealth keyless security system uses old fashioned Morse code as secret code. David Brown, project designer, said that you don’t need to learn all Morse code but only a few letters, perhaps three or four, is enough. Moreover, the Microcontroller has a wide tolerance on what it accepts for the “dots” and “dashes” of the code. This system even provides the user with options that can be used to practice its operation.

Hidden Security System
Download Project Documentation (zip)