Pachisi is a game similar to backgammon played mostly in Indian subcontinent, in which cones and cowries shells are used instead of counter and Dice. The game is played on a board between two persons, with the pieces moved in accordance with the throws of the cones or cowrie shells. This is an interesting game to test the ‘frustration quotient’ of the players.
The rectangular board includes a number of red and green circles. Opponents start from the same square and move in opposite directions. The player who reaches the ‘house’ first is declared winner.
The Electronic Pachisi gives one of the four different types of time bound instruction to the players:
- Forward along three green circle (F3 green)
- Forward along three red circles (F3 red)
- Background along two green circles (b2 green)
- Background along two red circles (b2 red).
These displays remain on for a set time and the players have to make their moves within that time. The process is continuous, and the displays appear randomly. Each player gets a change alternatively. Penalty may be imposed on a player if he does not move piece within the allowed time.
Description and Working of Pachisi Circuit Game using 555 IC
The circuit includes two monostable display devices and an intermittent oscillator. IC1 and IC2 are square wave oscillators. IC1 oscillates at an extremely low frequency compared to IC2. If IC1’s output is ‘low’, IC2 (a NAND gate oscillator) shuts off its output. Otherwise, it generates high frequency square waves.
IC3 is a divide-by-ten synchronous counter designed to reset at the arrival of every fifth pulse from IC2. One of its four output are held ‘high’ in the absence of an input signal IC4, a NOR gate module, keeps one of the LEDs ‘on’ at a time. The resultant signals from IC4 excite the monostable combinations formed by transistors T1 and T2, T3 and T4. Common-anode displays connected to the collector of the transistors display either F3 or b2. A simple regulated power supply provides power for all section.
Construction of Pachisi Circuit Game using 555 IC
The entire circuit can be housed in a suitable enclosure. A metallic box (24 x 12 x 4cm) would be ideal. The prototype carries the two LEDs and the 7-segment displays on its front panel. Its top may be painted with Pachisi pattern, thus doing away with the need for a separate board for playing the game.
Depending on the age of the players, the time allotted for each move may be varied. (Children take longer time to make up their mind.) For adults four to six seconds of move time would be enough, but for children more than 10 seconds may be needed. The time can be varied through potentiometer VR2.
Preset VR3 is adjusted for an appreciable rolling time. The speed setting is done through preset VR1
PARTS LIST OF PACHISI CIRCUIT GAME USING 555 IC
|Resistors (all ¼-watt, ± 5% Carbon)|
|R1 = 15 Ω, 1W
R2 = 200 Ω, ½ W
R3, R5, R9 = 680 Ω
R4, R8 = 33 KΩ
R6, R12, R17 = 10 KΩ
R7 = 330 Ω
R10, R13, R15 = 100 Ω
R11 = 250 Ω
R15 = 47 KΩ
R16 = 100 KΩ
VR1, VR3 = 100 KΩ Preset
VR2 = 1M Linear Potentiometer
|C1 = 1000 µF/25V (Electrolytic Capacitors)
C2 = 0.1 µF (Ceramic Disc)
C3 = 0.01 µF (Ceramic Disc)
C4 = 10 µF/12V (Electrolytic Capacitors)
|IC1 = NE555 (timer IC)
IC2 = CD4011 IC
IC3 = CD4017 IC
IC4 = CD4001 IC
T1 – T4 = BC108/BC107
D1 = 1N4001 or any general-purpose diode
ZD1 = 9.1V, 400mW ZENER Diode
LED1 = Red LED
LED2 = Green LED
DIS1, DIS2 = FND507 or any other common-anode display