Schematic Reference

LED Chaser Provides Three Game Functions

This circuit is essentially a light chaser but it can also be set to provides heads or tails (Two Up) or a Dice (die). It also has a speaker to simulate the sound of a spinning roulette wheel. Note that the dice and heads/tails features can be deleted if required and rules for the games created to suit individuals; eg, betting can be used or the numbers recorded and then totalled to get the highest score per game. IC1 is a 4046 phase locked loop (PLL) but only the voltage controlled oscillator (VCO) portion of the chip is used to provide the clock pulse for IC2, a 4017 decade counter/divider. In roulette wheel mode, switch S3 is pushed to start the game.


This charges the 10μF capacitor at pin 9 and as the capacitor discharges, the output frequency is slowly reduced to slow the rate of the chaser LEDs driven by IC2. In chaser mode, switch S2 is closed to provide a fixed frequency output from IC1. This can be varied over a wide range with potentiometer VR1. Transistor Q1 is also driven by the oscillator output of IC1 and it drives the speaker. Trimpot VR2 varies the sound level while switch S4 turns it off. Switch S5 selects Die or other (chaser/roulette). In Die mode, pin 6 is connected to the reset, pin 15, so that the circuit only counts to 6 whereas in the other modes it counts to 10 and displays all LEDs. Pin 12 drives transistor Q2 and two LEDs to provide the Heads/Tails function.