I am trying to setup the logic part of a door lock system that you would typically find in hotel rooms, safes or cars where you have to enter a sequence of numbers and the solenoid unlocks.
Anyone have any ideas on how I could do this? The system would have 5 buttons and 3 of them activate the solenoid, if a number other that those 3 is pressed the solenoid will not open or close if it was already activated by the right sequence. And also if the sequence of numbers isnt activated in the right order the door will not unlock.

I have the 5 simulated latching relays for each of the buttons, I am just having trouble with the actual logic for the sequence.
I am able to activate the solenoid when all 3 required buttons are pressed, and to not activate when any of the other buttons that arent required are pressed. But right now the system activates the solenoid regardless if the combination is pressed incorrectly.

Thanks

please forgive the very amateur nature of this drawing. In this situation all the buttons start at 1, and when pressed become a 0. The correct combination for this wiring is 1,2,3

Thanks but having all normally closed contacts wouldn't that cause conflicts?
Im gonna try this out tomorrow in class, ill lyk if i keep having issues.

I think you don't need the last AND logic before output 1, do you?
you would just need dead ends at 4 and 5?

Anyway ill mess with it some more tomorrow. Thanks again

The interesting part is the sequence matters... this is all ladder logic correct?

sequence will be b1, b2, b3. b4 and b5 not used

check1 = variable to make sure the first number is correct
check2 = variable to make sure the second number is correct
check3 = variable to make sure the third number is correct



I'm thinking something like this ^^

if 4 and 5 are dead ends, then the combination 1243 will work,

basically the circuit checks that 1 was pressed before 2, that 2 was pressed before 3, that 3 was pressed before 4 (its ok if 4 is never pressed so long as 3 is pressed), and if 3 was pressed before 5; if that is all true, the combination is correct and open/close the door/whatever

This makes a lot of sense; check var = regular output right?
Thanks

No problem

Ended up looking like this