CodeLock is AVR based electronic combination lock. This security system use microcontroller AT90S2313 or ATtiny2313 as main chip. If the code is entered in the correct sequence, then after 1 second the relay and the electric striker (in the door) switch on for 1 second and then switch off again. You can modify the code through 3×4 matrix keypad. Default user code (1234) is set up with a jumper.
Each pressed key is immediately confirmed with one short beep. Two short beeps follow after entering the right user code. One long beep appears when entering the wrong user code. The keypad is blocked for 20 seconds for each incorrect action. User code is retained even in the event of a power failure. You can use a LED diode instead of a Beeper.
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Project Documentation and Circuits