Memory Game

Abstract

The purpose of the project was to create a circuit schematic using an electronics kit, design a corresponding printed circuit board layout and assemble all the components onto the fabricated PCB. In this project memory game similar to the Simon game was created.  A preprogramed IC is used to light up LEDs in a random sequence and the player has to press the corresponding switches in the correct order.  Players have the option of choosing between four levels of difficulty and playing with or without sound.  The memory game is powered using three AA batteries.

Project Description

The schematic of the memory game was based on a kit from Carl’s electronics. The basic idea of the game is to have the player memorize and repeat the order that the LEDs in the game light up. A preprogrammed IC sends signals to a short sequence of the LEDs and then waits for a response from the player. Every time the player pushes down on a switch a particular circuit is closed. The IC checks if the correct circuits are closed in the right order. As soon as an incorrect move is made the IC will send a signal to the correct LED , LED the player incorrectly chose, and to the speaker which creates a buzzing sound indicating the player has lost the game.

The vias for the switches were slightly too small so the pins were filed down reduce their diameter.  Also, the silk screen for one of the diodes was labeled incorrectly (positive side was labeled negative). The diode had to be desoldered and switched back to the correct position in order for the board to properly function.  The kit came with a battery holder that had extremely loose connectors so a new battery pack from the IME lab was used to make the product more reliable.

A wooden box with the PCB as the lid was created to hold the board and battery pack conveniently while playing the game. The PCB “lid” could be removed to change the battery back.  A hole was opened up on the bottom of the box so that the on/off switch on the battery pack could be accessed.

Conclusion

I was able to fabricate and assemble a working memory game. The game successfully allows players to choose levels and turn on/off sound. When an incorrect move is made the game correctly recognizes the mistake. Through this project I learned the importance of every step of the PCB fabrication process. A slightly smaller via resulted in the pins components not fitting in the through-holes easily. An incorrectly diagramed silkscreen resulted in the entire board not functioning until the problem was found.

Future improvements:

1. Make a one sided board with all the wiring on the backside so only the game would show on the front
2. Make the board smaller so that it could be held in one hand and played using thumb.
3. Make final assembly smaller by using a 1.5 V button battery instead of 3 bulky AA.

Downloads

• Presentation (PDF)
• BOM (PDF)
• Schematic (PDF)