This circuit is very basic to build. To open a the lock which is connected to the K1 Load you must press each momentary switch in the correct sequence. The sequence used in this circuit is S1,S2,S3,S4. If any of the other switchs are pressed the circuit will reset and you will need to start over. Depending on how you wire the switchs, you can use any 4 switch combination.
View attachment Lock.gif
View attachment Lock.gif