For a horizontal sync pulse, we generate precisely the NTSC specified 5 ms pulse. NTSC specifies a vertical sync pulse width of 63.55 ms, however our code will use a 63.625 ms vertical sync pulse. We use this timing for a vertical sync pulse because it can be obtained by using the 16MHz clock and entering an ISR every 1018 cycles. This vertical sync pulse still produces a stable image when compared to the 63.55 ms vertical sync pulse and thus accuracy and video quality is not reduced.
In an effort to enforce safety in our design, we attached the user controls (accelerometers) using stranded wire to avoid tangling of the wires and possible exposure to the user. At points of connection, we used electrical tape to secure the area to prevent any possible contact with signals on the wire. The stranded wire also allowed for ease of mobility in controlling and moving the accelerometer. Also, by using long wires to separate the accelerometers from the PC board, we minimized the risk that a user could touch any exposed or open circuit components on the board.
Interference with other people's design
Our design did not utilize any form of RF transmission. As a result, our circuit does not cause any interference with any other group's design in terms of RF. Our circuit does produce oscillating frequencies for both the sound and video generation. However, unless other circuits are extremely nearby and extremely sensitive, our circuit will not produce significant noise because the signals are confined to within the wires of the board.
UsabilityThe user interface of our game is very versatile and can be used by most people. Individuals with handicaps such as impaired vision can still play because the sound produced will notify them when their ball has hit a paddle or brick. Since our game is designed for a black and white color scheme, color blind individuals do not suffer a disadvantage. Our hands-on user interface makes our game very simple and easy to learn, which is ideal for the young and the elderly. Our hands-on interface is ergonomically friendly in that it prevents repetitive button pushing or movement of a mouse. Our device prevents computer related repetitive strain injury (RSI) by offering a non-traditional user interface.