I'm designing a circuit to check 13 switches (a panel of machine)
I want to make a circuit that can keep the history of pressed switch
show by 13 led lights.This is to make sure I check them all.
When check again I can press reset all light turns off.
I found that 74HC74 D-flip flop would be suit, but I have to use many 74HC74.
What's wrong with seven 74HC74 chips? They are cheap. Too bulky?
You could use thirteen small SCRs. Each button turns on one SCR, which lights its LED. The reset button is normally-closed, and simply breaks the DC power to the whole project, thereby resetting all the SCRs. High technology! Of course, a small SCR costs about the same as a 74HC74.
Some folks use PIC microcontrollers for everything. You could do that here. They are small and cheap.