CodeLock AVR electronic combination lock is realised with Atmel AVR microcontroller AT90S2313 or ATtiny2313. Program in hex code is 2 kB long. User code is consisted of 1 to 8 digits. If you buy the chip than you can enter up to 8 user codes. 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. User code can be changed via 3×4 matrix keypad. Keypad for CodeLock can be bought at local electronic shop.
Initial user code (1234) is set up with a jumper. The jumper must be inserted before the voltage (12V) connection. The jumper must be removed after 2 beeps (after 5 to 15 seconds).
Source: Kripa Puri
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