ElectricSpidey said:
"The 10k VR is fine like that in a sim, but in real life you can create a direct short between VCC and the discharge pin."

While I certainly agree with you on that point, it has never caused a problem. FWIW, I first saw the circuit with a pot in that configuration in 1979 in an "Engineer's Notebook" by Forrest Mims III.

Reloadron said:
"Most roulette schemes I have see use a button that produces a burst of pulses on the 4017 Clock Input which slowly decays like a roulette wheel slowing down."

My preferred method for this is not a 555 astable, but a two-transistor VCO. I've used it both in roulette and digital dice circuits.

 

FWIW, I first saw the circuit with a pot in that configuration in 1979 in an "Engineer's Notebook" by Forrest Mims III.

Yeah, and it shows up in the second edition pages 96 and 97 on 555 circuits. The first notebook had the Blue covers and the Notebook II Yellow. Won't hurt anything but still does not solve why the thread starter's project won't work.

Ron

 

Another name for this is a "Wheel of Fortune" circuit. The main characteristic is having the oscillator frequency slowly decrease until it comes to a stop.

https://images.search.yahoo.com/sea...l+Of+Fortune+Circuit+Diagram.png&action=click

ak

 

.... and that one makes noise like the wheel!

Ron