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Advice Please: LCD Timer Project
I need what will basically be a digital stopwatch. It will need to be
an accurate LCD timer/clock that can record a huge number of splits to 1/60th of a second, and since nothing like what I need is on the market I'll obviously have to build one for myself, if this is possible. This may be a simple project, or a really complex one. But I was hoping to get ideas on where/how to start. Outisde of it's foot-print not being more than about 2 or 3 inches wide, the following is what I'm after... 1) Two digital displays: A) One for the main timer, which can be reset to zero at the press of a button. B) One that will show the latest split time, at the press of a button. 2) The ability to record/recall *at least* 256 splits. Any advice on what parts and where to get them would be greatly appreciated. Thanks a lot. Darren Harris Staten Island, New York. |
Darren Harris wrote:
I need what will basically be a digital stopwatch. It will need to be an accurate LCD timer/clock that can record a huge number of splits to 1/60th of a second, and since nothing like what I need is on the market I'll obviously have to build one for myself, if this is possible. This may be a simple project, or a really complex one. But I was hoping to get ideas on where/how to start. Outisde of it's foot-print not being more than about 2 or 3 inches wide, the following is what I'm after... 1) Two digital displays: A) One for the main timer, which can be reset to zero at the press of a button. B) One that will show the latest split time, at the press of a button. 2) The ability to record/recall *at least* 256 splits. Any advice on what parts and where to get them would be greatly appreciated. Thanks a lot. Darren Harris Staten Island, New York. I think I'd look into whatever stopwatch programs are available for handheld PDA's. There are some good deals out there for monochrome Palm OS devices. (In fact, I'd unload one of mine to the right buyer.) It seems that I've seen programs which might do what you desire. Certainly there are stopwatch programs out there. Do a Google search.... Much easier to program a computer (PDA) to do the above, than to build a dedicated hardware solution.... jak |
On Wed, 20 Oct 2004 12:52:32 -0500, "jakdedert"
wrote: Darren Harris wrote: I need what will basically be a digital stopwatch. It will need to be an accurate LCD timer/clock that can record a huge number of splits to 1/60th of a second, and since nothing like what I need is on the market I'll obviously have to build one for myself, if this is possible. This may be a simple project, or a really complex one. But I was hoping to get ideas on where/how to start. Outisde of it's foot-print not being more than about 2 or 3 inches wide, the following is what I'm after... 1) Two digital displays: A) One for the main timer, which can be reset to zero at the press of a button. B) One that will show the latest split time, at the press of a button. 2) The ability to record/recall *at least* 256 splits. Any advice on what parts and where to get them would be greatly appreciated. Thanks a lot. Darren Harris Staten Island, New York. I think I'd look into whatever stopwatch programs are available for handheld PDA's. There are some good deals out there for monochrome Palm OS devices. (In fact, I'd unload one of mine to the right buyer.) It seems that I've seen programs which might do what you desire. Certainly there are stopwatch programs out there. Do a Google search.... Much easier to program a computer (PDA) to do the above, than to build a dedicated hardware solution.... jak I'll second the PDA platform. Monochrome Palm devices have recently been available for $30US at Fry's, Sears, Ebay, computergeeks.com, surpluscomputers.net, and others. Most of these devices have a hardware clock with 100 clock ticks/second, so you can can get fractional seconds - however, 1/60 second doesn't divide well with 1/100 second pulses ;-) |
John writes:
On Wed, 20 Oct 2004 12:52:32 -0500, "jakdedert" wrote: Darren Harris wrote: I need what will basically be a digital stopwatch. It will need to be an accurate LCD timer/clock that can record a huge number of splits to 1/60th of a second, and since nothing like what I need is on the market I'll obviously have to build one for myself, if this is possible. This may be a simple project, or a really complex one. But I was hoping to get ideas on where/how to start. Outisde of it's foot-print not being more than about 2 or 3 inches wide, the following is what I'm after... 1) Two digital displays: A) One for the main timer, which can be reset to zero at the press of a button. B) One that will show the latest split time, at the press of a button. 2) The ability to record/recall *at least* 256 splits. Any advice on what parts and where to get them would be greatly appreciated. Thanks a lot. Darren Harris Staten Island, New York. I think I'd look into whatever stopwatch programs are available for handheld PDA's. There are some good deals out there for monochrome Palm OS devices. (In fact, I'd unload one of mine to the right buyer.) It seems that I've seen programs which might do what you desire. Certainly there are stopwatch programs out there. Do a Google search.... Much easier to program a computer (PDA) to do the above, than to build a dedicated hardware solution.... jak I'll second the PDA platform. Monochrome Palm devices have recently been available for $30US at Fry's, Sears, Ebay, computergeeks.com, surpluscomputers.net, and others. Most of these devices have a hardware clock with 100 clock ticks/second, so you can can get fractional seconds - however, 1/60 second doesn't divide well with 1/100 second pulses ;-) I bet the 1/60th probably came from the power line and they'd actually prefer 1/100th accuracy! --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/ Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/ +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html Note: These links are hopefully temporary until we can sort out the excessive traffic on Repairfaq.org. Important: Anything sent to the email address in the message header is ignored. To contact me, please use the feedback form on the S.E.R FAQ Web sites. |
"Darren Harris" wrote in message om... | I need what will basically be a digital stopwatch. It will need to be | an accurate LCD timer/clock that can record a huge number of splits to | 1/60th of a second, and since nothing like what I need is on the | market I'll obviously have to build one for myself, if this is | possible. Not sure how many 'huge' is, but an old Model 100 Radio Shack computer will do it. There's a M/L program you can download to give you several splits. N |
I know nothing at all about PDAs or programming. But from what I can
tell, it wouldn't suit my purpose anyway. I was visualizing two displays(like the big red numbers on those easy to read digital clocks). For power consumption reasons I assumed that this timer would have to be something I'd plug into an outlet. I could settle for a timer that would increment at 1/100th of a second instead of 1/60th. So I guess that would mean that I'd need 8 decimal places for the display that would show the split times. Anyway, from what I gather, what I want to do is too complicated, going by the recommdations so far. Or perhaps there is a way to use a PDA hidden in a specially built box where it would output to the kind of displays I need. Is this plausible? Thanks a lot. Darren Harris Staten Island, New York. |
On Thu, 21 Oct 2004 13:09:44 -0700, Darren Harris wrote:
I know nothing at all about PDAs or programming. But from what I can tell, it wouldn't suit my purpose anyway. I was visualizing two displays(like the big red numbers on those easy to read digital clocks). For power consumption reasons I assumed that this timer would have to be something I'd plug into an outlet. I could settle for a timer that would increment at 1/100th of a second instead of 1/60th. So I guess that would mean that I'd need 8 decimal places for the display that would show the split times. Anyway, from what I gather, what I want to do is too complicated, going by the recommdations so far. Oh, that's only because everybody jumped on that pocket thing. All you need is a clock oscillator, a counter, a few latches and display drivers, and some gating logic. You push "start", that gates on the counter (so you get a full cycle at start time - the oscillator is free-running), and then your "time 1" button latches the current count into display 1, your "time 2" button latches display 2, and so on. You can add displays all day long, if you want. Maybe a dozen parts, if you do it all with "discrete" chips. Or perhaps there is a way to use a PDA hidden in a specially built box where it would output to the kind of displays I need. Is this plausible? Yabbut, it's way overkill, or maybe "underkill." ;-) Like I said, you can do it with a few counters and latches. For a digital weenie like me, it's just a matter of connecting the dots. :-) Chips you might want to look at: 74HC393 - dual decade counter 74HC273 - 8-bit D FF (or edge-triggered latch) Oh, yeah, you'll need some kind of BCD-to-7-segment decoders, but you already knew that, right? ;-) Have Fun! Rich |
Rich Grise wrote:
On Thu, 21 Oct 2004 13:09:44 -0700, Darren Harris wrote: I know nothing at all about PDAs or programming. But from what I can tell, it wouldn't suit my purpose anyway. I was visualizing two displays(like the big red numbers on those easy to read digital clocks). For power consumption reasons I assumed that this timer would have to be something I'd plug into an outlet. I could settle for a timer that would increment at 1/100th of a second instead of 1/60th. So I guess that would mean that I'd need 8 decimal places for the display that would show the split times. Anyway, from what I gather, what I want to do is too complicated, going by the recommdations so far. Oh, that's only because everybody jumped on that pocket thing. All you need is a clock oscillator, a counter, a few latches and display drivers, and some gating logic. You push "start", that gates on the counter (so you get a full cycle at start time - the oscillator is free-running), and then your "time 1" button latches the current count into display 1, your "time 2" button latches display 2, and so on. You can add displays all day long, if you want. Maybe a dozen parts, if you do it all with "discrete" chips. Or perhaps there is a way to use a PDA hidden in a specially built box where it would output to the kind of displays I need. Is this plausible? Yabbut, it's way overkill, or maybe "underkill." ;-) Like I said, you can do it with a few counters and latches. For a digital weenie like me, it's just a matter of connecting the dots. :-) Chips you might want to look at: 74HC393 - dual decade counter 74HC273 - 8-bit D FF (or edge-triggered latch) Oh, yeah, you'll need some kind of BCD-to-7-segment decoders, but you already knew that, right? ;-) Have Fun! Rich Fun, I guess, but: http://www.intellitimer.com/ Sport's #1 Stopwatch Software for Palm OS handhelds and compatibles Intelli-products are now used in over 100 countries worldwide! Times, Totals, & Tabulates ....splits, finishes, and speeds for all sports! IntelliTimer: * Tri-Timer display; * Delta Time Tracking; * Multi-mode operation; * Unlimited event logging; * 50 split/finish times per event; * Accuracy to 1/100th second; * Event timing up to 99 hours; * Finish-time and group editing; * Editable descriptions and events; * Real-time split display and recording; * Editable descriptions and events; * Beaming to other Palm-enabled handhelds; * PC Desktop Companion;; * Print results; * Save results to Web page; * Save results to CSV file; * Create charts IntelliTimer: For the timings of your life! or maybe: http://www.palmspot.com/software/det...8a_98332.html: Banana Split Race Timer 2.0a Race Split Timer SHAREWARE- $25.00 from: Medical Informatics, Inc. Complete race timer which can be used for recording race results or on the course to record splits. Keeps track of laps, interval starts, multiple classes of racers, race groups (teams), racer names. Was originally designed as a XC ski race timer to track complex splits and interval starts for on-course coaching. Gives lap information, time from leader, time to next racer and much more. Racer registration screen allows you to enter names, classes, groups, and start delay for each racer. Full reporting on screen and export to memo pad. Improved split time display and performance of the program. You can now operate program with one hand! Instant Split display gives you everything you need to know. Now can also sort and display results by lap and class. If neither of these work, you can try: http://www.palmspot.com/software/det...08a_98332.html PocketTimer 2.1 COMMERCIAL- $49.95 from: Stevens Creek Software The handheld, inexpensive race timing solution, ideal for race directors, running clubs, or anyone else putting on an event that needs timing. Use it as primary finish line timing or as backup for existing timing gear. Record transition times in triathlons, split times at aid stations in an ultra, or anything else. Records bib#, place, time, and pace for thousands of racers. Download the results to your desktop computer in an easy-to-read format. - What's New! ----- New updates in this version: Times can be sorted by time or bib# export of data is controlled so user can specify place bib#, time, and/or pace to be exported in CSV or tab-delimited format. Or you might want to try: http://www.palmspot.com/software/det...21a_98332.html RaceTimes 1.2 SHAREWARE- $15.00 from: Nu-Log Pty Limited This program records times (up to 100) in hh:mm:ss using the hard buttons on the PalmPilot. Names (or numbers/boats) are recorded using graffiti (or the popup keyboard). A clock can be displayed on screen in either 12 or 24 hour mode. The PalmPilot may be turned off, and when the "Record" button is pressed, the time is recorded (and the Pilot turns on). The program was originally written to record sailing results, but is equally useful for any race or purpose where times need to be recorded to 1 second accuracy. More than one time can be recorded for the same second. Now you can output to the Serial Port. So you can Print to a Serial Printer (or Parallel Printer using a converter) or capture to a File (or print to your computer's printer) on a Computer using a Terminal program (does not require HotSync software) RaceTimes 1.2 or: http://www.palmspot.com/software/det...53a_98332.html or: http://www.a-metrics.com/laptrack1.htm or maybe something from he http://www.pilotzone.com/palm/util_time_pop.html Those are just from a quick search on Google for "Palm stopwatch program" There are many more.... jak |
Okay.
Since there doesn't seem to be another way, can anyone refer me to someone who may be able to build something like what I'm after? Thanks. Darren Harris Staten Island, New York. |
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" is not a valid email. On 29 Oct 2004 08:31:55 -0700, (Darren Harris) wrote: Okay. Since there doesn't seem to be another way, can anyone refer me to someone who may be able to build something like what I'm after? |
On Fri, 29 Oct 2004 13:33:55 -0500, John Fields wrote:
On 29 Oct 2004 08:31:55 -0700, (Darren Harris) wrote: Okay. Since there doesn't seem to be another way, can anyone refer me to someone who may be able to build something like what I'm after? --- What's a "split"? Apparently not just plain multiple displays, each with its own "latch" button, all started and clocked together. Cheers! Rich |
What's a "split"?
Apparently not just plain multiple displays, each with its own "latch" button, all started and clocked together. Cheers! Rich Splits = individual lap times. I'll settle for a single LCD display if I have to. Since this appears to be too complicated, perhaps I can start off with something simple. Does anyone know how to build a simple timer with an LCD screen that shows hours, minutes, and seconds? Thanks. Darren Harris Staten Island, New York. |
Splits = individual lap times. I'll settle for a single LCD display if I have to. Since this appears to be too complicated, perhaps I can start off with something simple. Does anyone know how to build a simple timer with an LCD screen that shows hours, minutes, and seconds? It's not terribly complicated, but either way you'll pretty much need to use a microcontroller. Check out www.maximic.com for LCD display driver chips, and look at www.atmel.com or www.microchip.com for microcontroller info. You could save some hardware time by using a ready-made LCD display, 16 character x 2 line displays are relatively common, cheap, and not overly complex to drive. To save some time coding you can skip the assembly language and look into one of the compilers out there, RVK Basic, Bascom Basic, PICBasic, C, etc. Another advantage of this approach is that if you don't like the way it works or think of a new feature you want, you simply tweak the code until it works the way you want it to. |
It's not terribly complicated, but either way you'll pretty much need to use
a microcontroller. Check out www.maximic.com for LCD display driver chips, and look at www.atmel.com or www.microchip.com for microcontroller info. You could save some hardware time by using a ready-made LCD display, 16 character x 2 line displays are relatively common, cheap, and not overly complex to drive. To save some time coding you can skip the assembly language and look into one of the compilers out there, RVK Basic, Bascom Basic, PICBasic, C, etc. Another advantage of this approach is that if you don't like the way it works or think of a new feature you want, you simply tweak the code until it works the way you want it to. Unfortunately, since I know nothing about microcontrollers, driver chips, or programming, can anyone advise me on how I can find someone who could do this? Thanks. Darren Harris Staten Island, New York. |
Darren Harris wrote:
What's a "split"? Apparently not just plain multiple displays, each with its own "latch" button, all started and clocked together. Cheers! Rich Splits = individual lap times. I'll settle for a single LCD display if I have to. Since this appears to be too complicated, perhaps I can start off with something simple. Does anyone know how to build a simple timer with an LCD screen that shows hours, minutes, and seconds? Unfortunately, driving an LCD screen isn't a simple thing; they are really designed to be driven using software. There may be front-end chips which simplify them, but LED 7-Segment displays are much easier to drive from discrete logic. Building a 'simple' timer with discrete, digital logic isn't as easy as it seems. You need 1) a timer source, like an oscillator circuit 2) a counter (or more like a set of counter chips) 3) logic to sample these counter outputs, and display the results on an the LED segments. At the least, this will require 1) a crystal oscillator/divider, like the philips hef4521b combination oscillator/divider chip. Using a crystal, you can generate accurate one second clock pulses 2) a set of bcd counters, one per decade of timing accuracy. 3) a set of LED 7-segment display drivers, one per digit. 4) some 7 segment displays 5) power supply 6) enclosure You can get fancy and multiplex the LED displays, thus cutting down on the number of chips required, but this increases the complexity a bit, requiring more logic. Note that a microcontroller costing less than a buck can replace 1-3 with a simple program of about 100 lines of assembler. Also, there are designs for discrete timer circuits out on the web, if you want to look and see what you are getting yourself into before starting. If you decide to try to show speeds, you'll need division as well, which is fairly easy in a microcontroller, and much harder with digital logic. -- Regards, Robert Monsen "Your Highness, I have no need of this hypothesis." - Pierre Laplace (1749-1827), to Napoleon, on why his works on celestial mechanics make no mention of God. |
"Darren Harris" wrote in message om... It's not terribly complicated, but either way you'll pretty much need to use a microcontroller. Check out www.maximic.com for LCD display driver chips, and look at www.atmel.com or www.microchip.com for microcontroller info. You could save some hardware time by using a ready-made LCD display, 16 character x 2 line displays are relatively common, cheap, and not overly complex to drive. To save some time coding you can skip the assembly language and look into one of the compilers out there, RVK Basic, Bascom Basic, PICBasic, C, etc. Another advantage of this approach is that if you don't like the way it works or think of a new feature you want, you simply tweak the code until it works the way you want it to. Unfortunately, since I know nothing about microcontrollers, driver chips, or programming, can anyone advise me on how I can find someone who could do this? I didn't either until a couple years ago, it was having an achievable goal like this that gave me the motivation and direction to learn it. |
"Darren Harris" wrote in message om... | It's not terribly complicated, but either way you'll pretty much need to use | a microcontroller. Check out www.maximic.com for LCD display driver chips, | and look at www.atmel.com or www.microchip.com for microcontroller info. You | could save some hardware time by using a ready-made LCD display, 16 | character x 2 line displays are relatively common, cheap, and not overly | complex to drive. To save some time coding you can skip the assembly | language and look into one of the compilers out there, RVK Basic, Bascom | Basic, PICBasic, C, etc. Another advantage of this approach is that if you | don't like the way it works or think of a new feature you want, you simply | tweak the code until it works the way you want it to. | | Unfortunately, since I know nothing about microcontrollers, driver | chips, or programming, can anyone advise me on how I can find someone | who could do this? If you look on the Microchip site you will find all the app notes you will need. Look at PIC Microcontrollers. http://www.microchip.com/ N |
"Darren Harris" wrote in message Darren, Your email is bogus. If you want this project, you will have to send me an email. hamilton AT dimensional DOT com |
"James Sweet" wrote in message news:rRVkd.720$nc.681@trnddc02...
"Darren Harris" wrote in message om... It's not terribly complicated, but either way you'll pretty much need to use a microcontroller. Check out www.maximic.com for LCD display driver chips, and look at www.atmel.com or www.microchip.com for microcontroller info. You could save some hardware time by using a ready-made LCD display, 16 character x 2 line displays are relatively common, cheap, and not overly complex to drive. To save some time coding you can skip the assembly language and look into one of the compilers out there, RVK Basic, Bascom Basic, PICBasic, C, etc. Another advantage of this approach is that if you don't like the way it works or think of a new feature you want, you simply tweak the code until it works the way you want it to. Unfortunately, since I know nothing about microcontrollers, driver chips, or programming, can anyone advise me on how I can find someone who could do this? I didn't either until a couple years ago, it was having an achievable goal like this that gave me the motivation and direction to learn it. Translation = Get up off my ass. :-) My experience is that I'll spend months running all over the internet trying to gather info on this, unless there is a step-by-step document(with visual aids) somewhere thet covers *every* detail.(It seems that nothing is ever really straight forward). :-) Darren Harris Staten Island, New York. |
Splits = individual lap times.
I'll settle for a single LCD display if I have to. Since this appears to be too complicated, perhaps I can start off with something simple. Does anyone know how to build a simple timer with an LCD screen that shows hours, minutes, and seconds? Unfortunately, driving an LCD screen isn't a simple thing; they are really designed to be driven using software. There may be front-end chips which simplify them, but LED 7-Segment displays are much easier to drive from discrete logic. Building a 'simple' timer with discrete, digital logic isn't as easy as it seems. You need 1) a timer source, like an oscillator circuit 2) a counter (or more like a set of counter chips) 3) logic to sample these counter outputs, and display the results on an the LED segments. At the least, this will require 1) a crystal oscillator/divider, like the philips hef4521b combination oscillator/divider chip. Using a crystal, you can generate accurate one second clock pulses 2) a set of bcd counters, one per decade of timing accuracy. 3) a set of LED 7-segment display drivers, one per digit. 4) some 7 segment displays 5) power supply 6) enclosure You can get fancy and multiplex the LED displays, thus cutting down on the number of chips required, but this increases the complexity a bit, requiring more logic. Note that a microcontroller costing less than a buck can replace 1-3 with a simple program of about 100 lines of assembler. Also, there are designs for discrete timer circuits out on the web, if you want to look and see what you are getting yourself into before starting. If you decide to try to show speeds, you'll need division as well, which is fairly easy in a microcontroller, and much harder with digital logic. And that represents the simple version? It seems that what I need is the same as what one of those racing watches that record lap times do, but with LCD screen/s as a read-out. Darren Harris Staten Island, New York. |
"Darren Harris" wrote in message om... | Translation = Get up off my ass. :-) | | My experience is that I'll spend months running all over the internet | trying to gather info on this, unless there is a step-by-step | document(with visual aids) somewhere thet covers *every* detail.(It | seems that nothing is ever really straight forward). :-) | | Darren Harris | Staten Island, New York. I emailed you with a good starting point and info. Does this actually work? N |
On Thu, 11 Nov 2004 21:44:53 GMT, Robert Monsen
wrote: If you decide to try to show speeds, you'll need division as well, which is fairly easy in a microcontroller, and much harder with digital logic. It doesn't have to be, since all you really have to do is change the clock speed. -- John Fields |
|
Darren Harris wrote:
Splits = individual lap times. I'll settle for a single LCD display if I have to. Since this appears to be too complicated, perhaps I can start off with something simple. Does anyone know how to build a simple timer with an LCD screen that shows hours, minutes, and seconds? Unfortunately, driving an LCD screen isn't a simple thing; they are really designed to be driven using software. There may be front-end chips which simplify them, but LED 7-Segment displays are much easier to drive from discrete logic. Building a 'simple' timer with discrete, digital logic isn't as easy as it seems. You need 1) a timer source, like an oscillator circuit 2) a counter (or more like a set of counter chips) 3) logic to sample these counter outputs, and display the results on an the LED segments. At the least, this will require 1) a crystal oscillator/divider, like the philips hef4521b combination oscillator/divider chip. Using a crystal, you can generate accurate one second clock pulses 2) a set of bcd counters, one per decade of timing accuracy. 3) a set of LED 7-segment display drivers, one per digit. 4) some 7 segment displays 5) power supply 6) enclosure You can get fancy and multiplex the LED displays, thus cutting down on the number of chips required, but this increases the complexity a bit, requiring more logic. Note that a microcontroller costing less than a buck can replace 1-3 with a simple program of about 100 lines of assembler. Also, there are designs for discrete timer circuits out on the web, if you want to look and see what you are getting yourself into before starting. If you decide to try to show speeds, you'll need division as well, which is fairly easy in a microcontroller, and much harder with digital logic. And that represents the simple version? It seems that what I need is the same as what one of those racing watches that record lap times do, but with LCD screen/s as a read-out. Sorry, I was just trying to point out the complexities involved. If you are just going to go out and buy a watch, and that works for you, fine. I thought you wanted to build something. Those watches you see are undoubtedly controlled by either a microcontroller, or by a custom built chip of some kind, containing the sorts of parts (on a miniature scale) that I described above. Almost anything with any real complexity is done in software these days. Trying to do this in discrete TTL logic, for example, requires up to 11 chips for a 5 decade display. You may be able to buy one of these watches, and hack into the buttons to control it. However, the buttons are probably integrated into the PCB, so it may take a bit of actual hacking. Doing a larger display using one of these would be practically hopeless. I'm sorry if this is not what you need, but you are asking for something that isn't trivial. It may seem that it would HAVE to be trivial by looking at the prices of these items these days. Those prices really reflect mass production, and economies of scale, rather than simplicity. -- Regards, Robert Monsen "Your Highness, I have no need of this hypothesis." - Pierre Laplace (1749-1827), to Napoleon, on why his works on celestial mechanics make no mention of God. |
John Fields wrote:
On Thu, 11 Nov 2004 21:44:53 GMT, Robert Monsen wrote: If you decide to try to show speeds, you'll need division as well, which is fairly easy in a microcontroller, and much harder with digital logic. It doesn't have to be, since all you really have to do is change the clock speed. This sounds like something I want to understand. Say I'm trying to display the speed of a slot-car, given a sensor that detects the start and end of the race. Clocks measure time. You have distance as a given of the design. How would you do this? Thanks -- Regards, Robert Monsen "Your Highness, I have no need of this hypothesis." - Pierre Laplace (1749-1827), to Napoleon, on why his works on celestial mechanics make no mention of God. |
Darren Harris wrote:
Thanks everyone. Sorry about the e-mail address. It is a remnant of my old(defunct) ISP, and is spam proof. my e.a. is (take out the "No-SPAM). I cleaned up my parameters some: 1) Two digital displays: A) One display for the main timer, which would show hours, minutes and seconds(99:59:59). To cut down on complexity, I'm willing to forego the fractions.(But accueacy is very important). B) And one display that will show the latest split time, at the press of a button. This would need 3 extra places. Six for the timer and three for the lap counter.(Unless a third display is more plausible for the lap counter). 2) And an on/off push-button power switch.(This device of course would have to be plugged into an outlet). The main timer/display itself should just run via a push-button, and a second push-button that will reset(but not stop) it when pressed. The split display should increment consecutive split times via a push button, and just show the static time since the previous button press.(It would be nice to have a recall function here). :-) How many of these do you need? How big do the digits need to be? Is this for production, or a hobby thing? -- Regards, Robert Monsen "Your Highness, I have no need of this hypothesis." - Pierre Laplace (1749-1827), to Napoleon, on why his works on celestial mechanics make no mention of God. |
"Robert Monsen" wrote in message news:6Wwld.606891$8_6.339694@attbi_s04... | How many of these do you need? How big do the digits need to be? Is this | for production, or a hobby thing? FWIW, I sent him the code for an assembly language program that gives you 49 timers in a Model 100, and a basic driver that offers 8 of them selected by the 8 function keys. He can futz around with that to his heart's content. He can pick up a Model 100 on eBay, often for less than a display would cost. NM [76670,326] Tracy Allen STIMEM.ASM Text, Bytes: 2941, Count: 69, 11-Aug-90 Title : Stopwatch timers, m/l source code Keywords: 100 200 ML TIMER TIMERS STOPWATCH SOURCE CODE ASSEMBLY LANGUAGE Source code for m/l routine that maintains 49 concurrent timers in sync with the M100 or T102 clock interrupt. The routines can be called from BASIC, to enable, read and set the individual timers. The accompanying file STIMES.100 is a BASIC loader and demo "stopwatch" program. The timers occupy 99 bytes above HIMEM 62740, along with the routines "hooked" to the background task, and the BASIC set, get and enable. [76670,326] Tracy Allen STIMES.100 Text, Bytes: 2780, Count: 109, 11-Aug-90 Title : Eight-channel stopwatch demo Keywords: 100 102 STOPWATCH TIMER WATCH BASIC LOADER Multiple stopwatch program has 8 concurrently running stopwatches. Press enter to start them all at once. Press F1 to F8 to get "lap time" or finish from stopwatch 1-8. Uses machine language timers hooked to the 100/102's internal 256/second time interrupt. There are three calls to the m/l, syntax described in this program, and in accompanying STIMEM.ASM file. This demo is set up to time in 1/4 second intervals. |
How many of these do you need? How big do the digits need to be? Is this
for production, or a hobby thing? I need only one initially, but I'm sure other guys that I associate with will also want one for themselves. But it's difficult to guess how many in the end. That's why getting a list of all of the parts needed so it can be duplicated is important.(Who knows. 50 guys may each want one). The digits need to be at lease 3 centimeters tall. As for what I need it for. I am a competitive gamer on arcade video games. And quite a few of us go for world records on various games and platforms on a regular basis. It would be nice to be able to time every level completed, as well as log the overall game time when playing(for strategic as well as other reasons). Thanks. Darren Harris Staten Island, New York. |
Darren Harris wrote:
How many of these do you need? How big do the digits need to be? Is this for production, or a hobby thing? I need only one initially, but I'm sure other guys that I associate with will also want one for themselves. But it's difficult to guess how many in the end. That's why getting a list of all of the parts needed so it can be duplicated is important.(Who knows. 50 guys may each want one). The digits need to be at lease 3 centimeters tall. As for what I need it for. I am a competitive gamer on arcade video games. And quite a few of us go for world records on various games and platforms on a regular basis. It would be nice to be able to time every level completed, as well as log the overall game time when playing(for strategic as well as other reasons). Thanks. Darren Harris Staten Island, New York. Here is the display (common cathode): http://www.digikey.com/scripts/DkSea...139499&Site=US Using a 1MHz oscillator with a programmable divider chip like an HEF4059B will yield an accurate 100Hz signal. oscillator: http://rocky.digikey.com/WebLib/CTS/...45HS,45HST.pdf HEF4059B: http://rocky.digikey.com/scripts/Pro...7&M=LDS-CA12RI Using that signal to display a counter is easy. Here is a simplified schematic: http://home.comcast.net/~rcmonsen/stopwatch.gif The strange OR gates are required to do leading 0 blanking. If you don't care about that, omit the gates. There is an on-off switch on the left, which gates the oscillator signal into the counter logic. There are also two buttons, one which will reset the counter to 0, and the other which will test the displays by turning on all the segments. You will need a power supply. A wall wart that puts out 8 volts or so, along with a 7805 regulator and a couple of caps will do the trick. Look up the 7805 on the National web site. -- Regards, Robert Monsen "Your Highness, I have no need of this hypothesis." - Pierre Laplace (1749-1827), to Napoleon, on why his works on celestial mechanics make no mention of God. |
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