Developing a Prototype of Concealed Codelock

Overview

The project aims to build a concealed codelock which can be used in a similar fashion as a safe clock as it uses the ATmega8 microcontroller.

Details

The project works by scanning the ADC4 channel of the ADC using the AVR ATmega8 where an internal RC oscillator running at 8MHz is being used for clocking. The microcontroller is connected off-board to a potentiometer that functions as a voltage divider. One of its ends is connected to +5V and to the Ground for the other. If changes would occur, the voltage divider is scanned continuously by the ADC. A 10K potentiometer is being used as the rotation sensor and being concealed means using a double potentiometer wherein one will be used for the lock and the other for some purpose.

To prevent random dialing over the hours of a random combination that would fit, the lock will reset itself every 8 seconds. The serial port is used for the initial configuration where a level converter is attached onto JP1. Some terminal program is required to configure the device. The device can be placed anywhere it fits by simple disconnecting the level converter after configuration.