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#1
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PC/electronics help needed
Greetings all.
Assume for a moment that I have no knowledge of electronics (not true, but I only know what I've picked up and that's rather patchy). I'm looking to make a little addon for my PC and I need a little help. I'm after making 3 time/date displays using 7-segment (numbers) and 10-segment (letters) LED displays. One of them should actually show the correct time, the others I'd like to show other static times, preferably with the option to change them occasionally. The latter parts should be within my reach but the actual clock is a bit more of a problem, our school was a bit crap and didn't actually teach us how to do that. I'd rather make it from scratch but I'll butcher an alarm clock if I have to. The other thing is that it needs to be powered from the PC's power supply, so it'll need to run on either 5V or 12V, with some form of battery backup to power just the real clock when the machine is switched off. If somehow it could be made to display the system's internal time that would be wonderful, but not necessary. Any help at all would be vastly appreciated. DjBx |
#2
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Daniel J Beardsall wrote:
...I'm looking to make a little addon for my PC and I need a little help. I'm after making 3 time/date displays using 7-segment (numbers) and 10-segment (letters) LED displays. One of them should actually show the correct time, the others I'd like to show other static times, preferably with the option to change them occasionally. The latter parts should be within my reach but the actual clock is a bit more of a problem, our school was a bit crap and didn't actually teach us how to do that. I would ask in the electronics groups. sci.electronics... Good luck. The other thing is that it needs to be powered from the PC's power supply, so it'll need to run on either 5V or 12V, with some form of battery backup to power just the real clock when the machine is switched off. If somehow it could be made to display the system's internal time that would be wonderful, but not necessary. Any help at all would be vastly appreciated. DjBx |
#3
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Not sure what you want but:
first, 5 or 12 from the PC is not problem, even get 5 vdc from the USB port, second: you want the system time thats displayed in the task bar on the bottom right of your monitor displayed on your gadget? Then would it be connected to the computer thru the parallel port or serial or USB? When computer shuts down, does this display keep going, like automatically switching to an internal clock, then back to computer when its turned on again? You could write a program to send any number you want out the parallel port, read he system time, send out the hoy=urs, then send out the minutes. On Thu, 02 Dec 2004 02:05:31 +0000, Daniel J Beardsall wrote: Greetings all. Assume for a moment that I have no knowledge of electronics (not true, but I only know what I've picked up and that's rather patchy). I'm looking to make a little addon for my PC and I need a little help. I'm after making 3 time/date displays using 7-segment (numbers) and 10-segment (letters) LED displays. One of them should actually show the correct time, the others I'd like to show other static times, preferably with the option to change them occasionally. The latter parts should be within my reach but the actual clock is a bit more of a problem, our school was a bit crap and didn't actually teach us how to do that. I'd rather make it from scratch but I'll butcher an alarm clock if I have to. The other thing is that it needs to be powered from the PC's power supply, so it'll need to run on either 5V or 12V, with some form of battery backup to power just the real clock when the machine is switched off. If somehow it could be made to display the system's internal time that would be wonderful, but not necessary. Any help at all would be vastly appreciated. DjBx |
#4
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The problem with an alarm clock is that the chip is
completely contained. The only information coming out would be seven segment displays - multiplexed. You would have to convert that back to some usable form OR build a memory device to store those multiplexed seven segment outputs and then drive the other displays. Four digits times seven segments plus AM/PM is 29 D flipflop latches and LED display drivers. What type of time do you want to store? For example, if time of day, then the alarm clock solution is better. AC powered clocks synchronize with the 60 Hz power line - whose accuracy is traceable to the National Bureau of Standards. To avoid the complexity of same, the alarm clock would be a good foundation to start construction. You would probably have to beef up or supplement the alarm clock's power supply to power your latching registers and two additional displays. Another alternative is to start from scrap with a single chip computer. Again, your timing crystal accuracy is just another consideration. But a single chip computer affords you great flexibility to enhance your design. Daniel J Beardsall wrote: Greetings all. Assume for a moment that I have no knowledge of electronics (not true, but I only know what I've picked up and that's rather patchy). I'm looking to make a little addon for my PC and I need a little help. I'm after making 3 time/date displays using 7-segment (numbers) and 10-segment (letters) LED displays. One of them should actually show the correct time, the others I'd like to show other static times, preferably with the option to change them occasionally. The latter parts should be within my reach but the actual clock is a bit more of a problem, our school was a bit crap and didn't actually teach us how to do that. I'd rather make it from scratch but I'll butcher an alarm clock if I have to. The other thing is that it needs to be powered from the PC's power supply, so it'll need to run on either 5V or 12V, with some form of battery backup to power just the real clock when the machine is switched off. If somehow it could be made to display the system's internal time that would be wonderful, but not necessary. Any help at all would be vastly appreciated. |
#5
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Not sure what you want but:
first, 5 or 12 from the PC is not problem, even get 5 vdc from the USB port, Yes I know, I intend to run it off one of the internal Molex connectors. second: you want the system time thats displayed in the task bar on the bottom right of your monitor displayed on your gadget? Then would it be connected to the computer thru the parallel port or serial or USB? Yes. Any of those, whichever turns out to be easiest. Which from what I've gathered would be parallel. When computer shuts down, does this display keep going, like automatically switching to an internal clock, then back to computer when its turned on again? You could write a program to send any number you want out the parallel port, read he system time, send out the hoy=urs, then send out the minutes. Yes, I'd like the clock to be sort of independent with occasional updates from the PC clock (mostly to save the hassle of setting it manually). The program isn't the problem, I could knock something up in VB, it's getting something that can translate my outputs and display it that's the problem. DjBx |
#6
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The problem with an alarm clock is that the chip is
completely contained. The only information coming out would be seven segment displays - multiplexed. You would have to convert that back to some usable form OR build a memory device to store those multiplexed seven segment outputs and then drive the other displays. Four digits times seven segments plus AM/PM is 29 D flipflop latches and LED display drivers. The other displays would be independent of the actual clock, if that's what you mean. And yes, when I mentioned butchering an alarm clock that was mostly as a last-resort kind of option. What type of time do you want to store? For example, if time of day, then the alarm clock solution is better. AC powered clocks synchronize with the 60 Hz power line - whose accuracy is traceable to the National Bureau of Standards. To avoid the complexity of same, the alarm clock would be a good foundation to start construction. You would probably have to beef up or supplement the alarm clock's power supply to power your latching registers and two additional displays. The problem there is that I'm not in the US, I'm in the UK, and our electrical supply isn't quite so simple. It's mostly 50Hz but can fluctuate wildly, which often interferes with clocks. Besides, I'm not looking to run it off direct mains, I'm looking to run it off computer power, so a battery-powered alarm clock was more what I had in mind. Another alternative is to start from scrap with a single chip computer. Again, your timing crystal accuracy is just another consideration. But a single chip computer affords you great flexibility to enhance your design. Now you're talking. But I wouldn't know where to start hooking something like that into something capable of driving LED segment displays. Which I suppose is ultimately the help I'm after. Thankyou for your response. DjBx |
#7
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Daniel J Beardsall wrote:
The problem with an alarm clock is that the chip is completely contained. The only information coming out would be seven segment displays - multiplexed. You would have to convert that back to some usable form OR build a memory device to store those multiplexed seven segment outputs and then drive the other displays. Four digits times seven segments plus AM/PM is 29 D flipflop latches and LED display drivers. The other displays would be independent of the actual clock, if that's what you mean. And yes, when I mentioned butchering an alarm clock that was mostly as a last-resort kind of option. What type of time do you want to store? For example, if time of day, then the alarm clock solution is better. AC powered clocks synchronize with the 60 Hz power line - whose accuracy is traceable to the National Bureau of Standards. To avoid the complexity of same, the alarm clock would be a good foundation to start construction. You would probably have to beef up or supplement the alarm clock's power supply to power your latching registers and two additional displays. The problem there is that I'm not in the US, I'm in the UK, and our electrical supply isn't quite so simple. It's mostly 50Hz but can fluctuate wildly, which often interferes with clocks. Besides, I'm not looking to run it off direct mains, I'm looking to run it off computer power, so a battery-powered alarm clock was more what I had in mind. Another alternative is to start from scrap with a single chip computer. Again, your timing crystal accuracy is just another consideration. But a single chip computer affords you great flexibility to enhance your design. Now you're talking. But I wouldn't know where to start hooking something like that into something capable of driving LED segment displays. Which I suppose is ultimately the help I'm after. Thankyou for your response. DjBx I'm still not sure what you're trying to do, precisely, but maybe this will stimulate some ideas. http://www.rentron.com/Products/SLED4C.htm |
#8
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"Daniel J Beardsall" wrote in message ... [snip description of clock project] It is likely that there are commerically available and assembled products that either do exactly what you want or something similar. I've come across clock/timing devices with PC interfaces, as well as general purpose displays with PC interfaces. It would be worth investigating. Various companies make "electronic kits", "hobby kits", "learning kits", or whatever you want to call them... kits with all the parts and instructions you need to assemble some simple electronic device. If you google hard you'll find led clocks, timers, programmable displays, displays that interface with PC ports, etc. One or more of those kits might provide a starting point. There are many websites where people document their school or hobby projects. You should be able to find some websites that contain usefull information on projects that have something in common with yours. For example, people have interfaced all sorts of things to their PC, and over the years I've run across quite a few sites with detailed directions, schematics, parts lists, source code, etc. If you find something close you can lift part of the HW design and/or SW. If there is a good library and/or bookstore near you, you should be able to find not only books on electronic design basics, but electronic "cookbooks" that have schematics for all sorts of basic circuits. Having said all that, the suggestion that you take this discussion to an electronics newsgroup or web forum was truly the best one. For there you are likely to find a higher percentage of people who have the required experience, and hopefully interest and willingness to guide you. When you introduce yourself, be sure to talk a little about what hardware experience you have. Have you ever designed something with integrated circuits and discrete components? Have you ever selected and purchased all the parts, and wired them up on a breadboard? Have you done board layout/routing, and made or purchased a PCB? Also talk a little about what software development experience you have. That way people can steer you in the best direction. Have fun. |
#9
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It's real easy in VB.net, but remember, XP will not allow you to
program the ports, you need a "kernal driver" that runs in a special mode. This link explains it: http://www.logix4u.net/inpout32.htm My I/O programs start by calling ShellExec to run a script that puts you into the proper user mode. On Fri, 03 Dec 2004 06:12:45 +0000, Daniel J Beardsall wrote: Not sure what you want but: first, 5 or 12 from the PC is not problem, even get 5 vdc from the USB port, Yes I know, I intend to run it off one of the internal Molex connectors. second: you want the system time thats displayed in the task bar on the bottom right of your monitor displayed on your gadget? Then would it be connected to the computer thru the parallel port or serial or USB? Yes. Any of those, whichever turns out to be easiest. Which from what I've gathered would be parallel. When computer shuts down, does this display keep going, like automatically switching to an internal clock, then back to computer when its turned on again? You could write a program to send any number you want out the parallel port, read he system time, send out the hoy=urs, then send out the minutes. Yes, I'd like the clock to be sort of independent with occasional updates from the PC clock (mostly to save the hassle of setting it manually). The program isn't the problem, I could knock something up in VB, it's getting something that can translate my outputs and display it that's the problem. DjBx |
#10
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AC electric cannot vary wildly because all grid generators
must match up perfectly with all others - or the entire grid collapses. To find a clock that varies wildly, visit a PC clock. That clock is way too inaccurate to control the 50 Hz grid - where timing accuracy is essential. Use a PC as the timing source. Therefore you only need write special software to write to displays- ie driven through parallel ports. But then why bother with fancy hardware displays? You can put up clock displays in Windows on the monitor. Previously posted was using an alarm clock 'kludge' - every other display is independent of the actual clock - except when the display number is first latched from a master display. Appreciate everything posted up to now is perfectly matching your request - because details are missing. What are the details? For example, the grid 50 Hz remains a most accurate source of timing which is why AC electric clocks remain on time every day - without resetting every week. If 50 Hz AC is not accurate enough, then anything in a PC or in the embedded processor is even worse. IOW you did not provide a necessary detail such as the number for timing accuracy. You did not say where those other displays get their numbers. Are you trying to display a time of day, or time of event. For that matter, what is wrong with a controller from a defective microwave oven? How to connect to a display? First select the display. Then find the driver chip for that type of display. IOW download datasheets. Read some 3 or eight pages chock full of information (assume something like 15+ minutes per page). If that example (rentron.com) is what you want, then why not buy it? I remain completely confused by what you are trying to do. If 50 Hz AC power is not accurate enough, then this example is even worse. Just more little contradictory details that completely confused me. It is possible that you have not yet learned an engineer's mentality. This project is how you learn so much. Same reason why to teach why the military want people educated in the temperament of reality. Notice what you may have perceived as a simple project might take weeks. Something that would become obvious once you first list those details. The military teaches their future officers to be engineers. To learn that reality is not as simplistic as taught in secondary school. To learn temperament that comes from putting initial ideas into reality. Making ideas into reality is rarely taught in general education. We learn it by doing what you are trying to accomplish here. Currently, you have starve your request for information with insufficient details. Daniel J Beardsall wrote: The problem with an alarm clock is that the chip is completely contained. The only information coming out would be seven segment displays - multiplexed. You would have to convert that back to some usable form OR build a memory device to store those multiplexed seven segment outputs and then drive the other displays. Four digits times seven segments plus AM/PM is 29 D flipflop latches and LED display drivers. The other displays would be independent of the actual clock, if that's what you mean. And yes, when I mentioned butchering an alarm clock that was mostly as a last-resort kind of option. What type of time do you want to store? For example, if time of day, then the alarm clock solution is better. AC powered clocks synchronize with the 60 Hz power line - whose accuracy is traceable to the National Bureau of Standards. To avoid the complexity of same, the alarm clock would be a good foundation to start construction. You would probably have to beef up or supplement the alarm clock's power supply to power your latching registers and two additional displays. The problem there is that I'm not in the US, I'm in the UK, and our electrical supply isn't quite so simple. It's mostly 50Hz but can fluctuate wildly, which often interferes with clocks. Besides, I'm not looking to run it off direct mains, I'm looking to run it off computer power, so a battery-powered alarm clock was more what I had in mind. Another alternative is to start from scrap with a single chip computer. Again, your timing crystal accuracy is just another consideration. But a single chip computer affords you great flexibility to enhance your design. Now you're talking. But I wouldn't know where to start hooking something like that into something capable of driving LED segment displays. Which I suppose is ultimately the help I'm after. |
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