This is a simple 8-bit binary counter using a NE555 timer IC and a CD4020 binary counter.
Eight LEDs display the binary count, going up based on the NE555 astable timer timing, which can be controlled from a potentiometer..

I made this for Week 3 of Hack Club's Resolution Program's Hardware Pathway.

An NE555 timer, configured in astable mode, generates a square-wave clock signal with a 100k potentiometer that determines its speed.
A CD4020 binary counter recieves the clock signal and increments the counter which is outputted in binary via 8 LEDs..

See it here!