You’re annoyed when someone turned on your Hi-Fi without your permission first? You wish there is some kind of lock, which can prevents this type of incident in the future?
Well, if you don’t mind, spend few minutes by reading here, as you will learn how to build a concealed codelock today…
Here how is works:
You will need an ATMEGA8, which it will use as the microcontroller for this project. It will frequently scans the ADC4 channel of the ADC, where is fully connected offboard to a potentiometer. The pot will act as a voltage divider, the one end of it is connected to +5V and the other one will connect to the Ground. The ADC scans the divider continuously to detect if there any change has been happened.
The lock will resets itself every 8 seconds (Hehe, this for prevent those nasty person to try the random dialing over the hours). Cool, isn’t it? The initial configuration is done via the serial port, and a proper code is in this form:
The lock does not have a code set! Provide one:
Current combination: A
Current combination: AB
Current combination: ABC
Current combination: ABCD
Current combination: ABCDC
Current combination: ABCDCB
Current combination: ABCDCBA
Final sequence: ABCDCBAe*
Thus, you would need to turn the dial to D, then A and a few times to B and C, for open the lock here.
Note: You have to dial the last symbol FIRST, if you want to unlock the code!
Since this is a project that using the ATMega8, so you can mount it into the Hi-Fi, by simply “impost” it as the Volume tuner! Refer to the below figure to find more…