I am designing a system which only have 2 input (x and y) and the system will unlock when password 10010 is entered, with 100 as y and 10 as x. The sequence of the password is from left to right.

I have done a simple lock and unlock circuit enter image description here

But I found it difficult to add a reset button to clear all digits entered asynchronously and a X digits detector to show the output of the number of digits of the password currently detected on the X input. Any idea how and where should I add these? And am I on the right track?

  • 2
    \$\begingroup\$ no, you are not on the right track ... it is usually difficult to modify an existing circuit for new functionality, as you have learned with the reset button ... start from scratch with state diagrams for the lock \$\endgroup\$
    – jsotola
    Apr 10, 2022 at 16:03
  • \$\begingroup\$ A better description would also help. Why, for example, are you ANDing x and y? \$\endgroup\$
    – jonk
    Apr 11, 2022 at 8:18


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