The wheel of fortune game circuit is a kind of roulette wheel game, where 10 LEDs are used, and once the user initiates the game, the LEDs begin sequencing randomly until a single LED remains illuminated. The result being extremely random, it becomes impossible to predict which LED will be ON and whether it will be the fortunate one or not for the user.
It is easy to build a wheel of fortune with 10-sided die for many applications.
How the Circuit Works
As is given, the wheel of fortune starts spinning when switch S1 is pressed. The pressing results in pin 1 of IC 7413 going high. There is an oscillator at IC 7413 which is started and wave pulses begin switching pin 14. This 14th pin is part of a four bit counter IC2. When S1 is released the oscillation comes to a halt.
IC2 also counts the number of pulses the system goes through while S1 was open. A frequency that is suitable for the oscillator that is high enough is chosen to stop the player from cheating by halting the wheel at a certain spot.
The information of four bits is fed to BCD and IC3, a decimal converter. Until the counter DCBA is lower than 1001, one of the 10 outputs of IC3 stays low. That is signaled by an on LED light. For instance, when DCBA = 0110, output 6 of IC3 will be low and this will light up D7.
The IC 7445 is capable of decoding only 10 of the total 16 probable stages. Since from 1010 to 1111, all the outputs are high for IC3, no LED is lit. This may be counted as an end of the player’s turn.
The IC3 may be replaced by ‘one of a sixteen’ decoder, such as 24 pin type 74154 with half dozen LEDs with a series of resistors. This circuit will act as a wheel of fortune with 16 dies.