Circuit diagram of electronic door lock security key system

This is the circuit diagram of the electronic door lock security key system. This means that this security system circuit is a combination of the keys themselves (not mechanical ). The output can be connected to drive a relay to open the door (usually a motor ).

This is a very simple electronic door lock circuit with a 7-digit security code. Note that the keys that form the code must be pressed in time without delay. Using the correct keys, if the correct code is correct it will activate output Q7 for about 4 seconds, driving transistor Q2, which can be used to activate a relay and open the door, or can be used for any other circuit . An LED is used to activate a visual indication . The seven-digit combination code for the above circuit is: 1704570, but the combination of the security key can be changed by swapping the connections between the output of counter IC 1 and the switches.