I have this component called a breadboard friend. It has a 9V battery that is lowered to 5v so we can power most AOI logic chips. It has a built in 555 timer and a potentiometer. It has 4 leds to link outputs from our logic circuits to - and it has 4 spst switches that are used to simulate binary values: 0000 or 1000 etc.

What I want to do is make another part of this circuit that can simulate counting in binary for me up to X values. This way I can plug in the switches to the digital output and maybe press a switch to increment through the truth table.

I was thinking I could use the onboard 555 timer and use that somehow but I am lost.

  • 1
    \$\begingroup\$ "AOI Chips" - What? \$\endgroup\$ – Connor Wolf Nov 5 '10 at 5:43

Wire the 555 as a one-shot to make a clock signal for a binary counter IC (eg. 74LS93) that single-steps every time the 555 is fired.

  • \$\begingroup\$ I always forget to tell people to use counter ICs. I have not had to get something like a binary counter for a project in years. +1 \$\endgroup\$ – Kortuk Nov 5 '10 at 3:27

Take flip-flops for the state of the counter. Use logic tied from output to input(called next state logic) to give the counting. Use the square wave from the 555 timer to give your clock signal.


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