This is a simple password circuit that can run any electric device when a true password inserted
the circuit based on IC counter 4017 that used in sequentially LED flasher and other applications.
When you press S1 then S2 then S3 then S4 the relay be turn ON otherwise the relay stay turn OFF.
the keys that connected to pin 15 of the IC reset the circuit so if you pressed 2 first pass code correctly by pressing any false key the circuit reset the first correct codes.
you have to configuration the S1 to S4 as you want for example if you want to make the password 7460 so you have to connect S1 to number 7 in the keypad and S2 to number 4 and S3 to number 6 and S4 to number 0 in the keyboard.
When you press S1 then S2 then S3 then S4 the relay be turn ON otherwise the relay stay turn OFF.
the keys that connected to pin 15 of the IC reset the circuit so if you pressed 2 first pass code correctly by pressing any false key the circuit reset the first correct codes.
you have to configuration the S1 to S4 as you want for example if you want to make the password 7460 so you have to connect S1 to number 7 in the keypad and S2 to number 4 and S3 to number 6 and S4 to number 0 in the keyboard.
in following video you can see how it work.
Parts list:
IC4017
Relay 12v
Transistor 2N3904 or any other NPN transistor
Diode 1N4007
Diode 1N4148(5pcs)
Capacitor 100uF
Resistor 100K(2pcs)
Resistor 10K
Resistor 1K
Push button switch(10pcs)
LED
Parts list:
IC4017
Relay 12v
Transistor 2N3904 or any other NPN transistor
Diode 1N4007
Diode 1N4148(5pcs)
Capacitor 100uF
Resistor 100K(2pcs)
Resistor 10K
Resistor 1K
Push button switch(10pcs)
LED
