So im trying to make a combinational lock in proteus. One of the issue i've come across is one of my button which is labelled "reset" output high even if its not press but when I connect a logic probe to the line, the cable becomes normal. The second issue is there is a sequence detector that output 1 when there is 1111 input sequence, it was working as intended but when I add the button labeled reset, the said detector output 1 when the input sequence is 111 and 1111. Im also open for suggestion to improve my project, thank you

 

Hi

1. You are mixing IC families. That is bad for various reasons. Use only a single IC family. I suggest using CD4000 family unless there is a compelling reason not to (like hi speed, for example, which is not a requirement for this circuit).

2. Implement a POR (Power On Reset) circuit to initialize all devices to a specific state (like FF's for example), or the circuit could power up in an unknown state.

However, I did try the reset button and it behaved normally (output hi when pressed, low when not pressed).

Re-post your circuit after you've changed the circuit to use one IC family (preferably CD4000)