writerveggieastroprof

Student "edition" found at {csi dot journalspace dot com}.

Maybe I shouldn't have started this blog now, not with everything that's been going on.

In the two-hour Integrated Computer Systems session of my class for the ninth week of the second term, one of the groups finally got the two-buzzer game show circuit to work.

It used the design where the switch or buzzer is parallel to an inverter from a five volt source. So if the buzzer is not pressed, the rest of the circuit receives a "low", otherwise, the low is superceded by a high from the "merge" in the current river.

This is different from the first design I gave them, with the switch bridging the five volt source from the rest of the circuit, that on the other side of the switch is connected to a a small resistance and to the ground. This is to prevent a short circuit happening between the high and low source when the switch is pressed, which may have prevented it from working.

Instead of using an exclusive or gate between the two inputs to power the enable of the two D flip-flops they had, each of the two inputs were used as the enable to power the input to the two latches. Either way having only one of the two buzzers pressed would have had one of the two Light Emitting Diodes at the end of the circuit to light up, but it didn't.

The second set up worked though, although we have no idea why the first one didn't.

In my opinion though, the first circuit would have been easier to expand into eight buzzers (with less gates involved) while the second one seems to have more gates to use when expanded.

There may be alternatives that could be used to minimize the number of gates used in either circuit, and that is what the students have to find out next. It's up to them if they want to go to three buzzers first, or to go straight to eight.

They could use an eight-bit multiplexer to accept just the first input from the eight buzzers, or, in our merging with the concepts from the first part, they could use the parallel port of the PC.

Session 1399 has to learn to think big. Class dismissed.

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Previous Entry :: Next Entry Mood: Wanting New Neural Paths Read/Post Comments (0) Share on Facebook		2006-11-13 10:13 AM When Something Doesn't Work, Stop Using It and Take Another Path Student "edition" found at {csi dot journalspace dot com}. Maybe I shouldn't have started this blog now, not with everything that's been going on. In the two-hour Integrated Computer Systems session of my class for the ninth week of the second term, one of the groups finally got the two-buzzer game show circuit to work. It used the design where the switch or buzzer is parallel to an inverter from a five volt source. So if the buzzer is not pressed, the rest of the circuit receives a "low", otherwise, the low is superceded by a high from the "merge" in the current river. This is different from the first design I gave them, with the switch bridging the five volt source from the rest of the circuit, that on the other side of the switch is connected to a a small resistance and to the ground. This is to prevent a short circuit happening between the high and low source when the switch is pressed, which may have prevented it from working. Instead of using an exclusive or gate between the two inputs to power the enable of the two D flip-flops they had, each of the two inputs were used as the enable to power the input to the two latches. Either way having only one of the two buzzers pressed would have had one of the two Light Emitting Diodes at the end of the circuit to light up, but it didn't. The second set up worked though, although we have no idea why the first one didn't. In my opinion though, the first circuit would have been easier to expand into eight buzzers (with less gates involved) while the second one seems to have more gates to use when expanded. There may be alternatives that could be used to minimize the number of gates used in either circuit, and that is what the students have to find out next. It's up to them if they want to go to three buzzers first, or to go straight to eight. They could use an eight-bit multiplexer to accept just the first input from the eight buzzers, or, in our merging with the concepts from the first part, they could use the parallel port of the PC. Session 1399 has to learn to think big. Class dismissed. Read/Post Comments (0) Previous Entry :: Next Entry Back to Top