|
LED PIC based counter?
Anyone know of a PIC based frequency counter using the low current 7 segment
readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. Tnx, Dale W4OP |
On Wed, 11 Feb 2004 13:47:22 GMT, "Dale Parfitt"
wrote: Anyone know of a PIC based frequency counter using the low current 7 segment readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. have a look at... http://www.qsl.net/om3cph/om3cph.html it may be what you are looking for |
On Wed, 11 Feb 2004 13:47:22 GMT, "Dale Parfitt"
wrote: Anyone know of a PIC based frequency counter using the low current 7 segment readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. have a look at... http://www.qsl.net/om3cph/om3cph.html it may be what you are looking for |
In article , "Dale Parfitt"
writes: Anyone know of a PIC based frequency counter using the low current 7 segment readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. A problem there is finding an LED numeric display with low current per segment or a driver capable of higher peak current for sequential strobing of an array of LEDs. The only thing that I could recommend is the miniature LED array with integral magnifying lens and filter that HP made for their first scientific calculator, the HP-35. In the HP 1979 Optoelectronic databook, the 5082-7200 series and 5082-7400 series have varying numeric character assemblies from 2 to 16 digits. The 5082-7240 is an 8-digit assembly "capable of being driven by MOS circuits" (according to catalog text, apparently in reference to calculator use). Average per segment current is about 0.5 mA and peak current (for strobing array) is 5.0 mA. The character height is 2.59mm by 1.52mm wide but magnified by the integral plastic lens. I've stared at that HP-35 calculator display long enough without eyestrain from the appearance (only headaches from results not meeting expectations). Brightness is okay to use in a well-lighted office environment but gets a bit dim outdoors in the shade (such as a QRP outing?). I don't know if they are made any more, couldn't get through the Agilent-HP site to find them. Someone makes those little LED numeric arrays now, used in hand-carried frequency counters. A PIC would strobe segments and the program could be adjusted to optimize the on-time duty cycle for a particular segment. In using unmagnified LEDs, the average segment current is around 5 mA minimum for sufficient brightness but that is variable depending on the molded-in filtering for various colors (attenuates brightness). Strobing would require higher peak currents. Len Anderson retired (from regular hours) electronic engineer person |
In article , "Dale Parfitt"
writes: Anyone know of a PIC based frequency counter using the low current 7 segment readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. A problem there is finding an LED numeric display with low current per segment or a driver capable of higher peak current for sequential strobing of an array of LEDs. The only thing that I could recommend is the miniature LED array with integral magnifying lens and filter that HP made for their first scientific calculator, the HP-35. In the HP 1979 Optoelectronic databook, the 5082-7200 series and 5082-7400 series have varying numeric character assemblies from 2 to 16 digits. The 5082-7240 is an 8-digit assembly "capable of being driven by MOS circuits" (according to catalog text, apparently in reference to calculator use). Average per segment current is about 0.5 mA and peak current (for strobing array) is 5.0 mA. The character height is 2.59mm by 1.52mm wide but magnified by the integral plastic lens. I've stared at that HP-35 calculator display long enough without eyestrain from the appearance (only headaches from results not meeting expectations). Brightness is okay to use in a well-lighted office environment but gets a bit dim outdoors in the shade (such as a QRP outing?). I don't know if they are made any more, couldn't get through the Agilent-HP site to find them. Someone makes those little LED numeric arrays now, used in hand-carried frequency counters. A PIC would strobe segments and the program could be adjusted to optimize the on-time duty cycle for a particular segment. In using unmagnified LEDs, the average segment current is around 5 mA minimum for sufficient brightness but that is variable depending on the molded-in filtering for various colors (attenuates brightness). Strobing would require higher peak currents. Len Anderson retired (from regular hours) electronic engineer person |
Hey! I think I have some of those. Since I'm never going to use them, I
suppose I could part with them. But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. "Avery Fineman" wrote in message ... In article , "Dale Parfitt" writes: Anyone know of a PIC based frequency counter using the low current 7 segment readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. A problem there is finding an LED numeric display with low current per segment or a driver capable of higher peak current for sequential strobing of an array of LEDs. The only thing that I could recommend is the miniature LED array with integral magnifying lens and filter that HP made for their first scientific calculator, the HP-35. In the HP 1979 Optoelectronic databook, the 5082-7200 series and 5082-7400 series have varying numeric character assemblies from 2 to 16 digits. The 5082-7240 is an 8-digit assembly "capable of being driven by MOS circuits" (according to catalog text, apparently in reference to calculator use). Average per segment current is about 0.5 mA and peak current (for strobing array) is 5.0 mA. The character height is 2.59mm by 1.52mm wide but magnified by the integral plastic lens. I've stared at that HP-35 calculator display long enough without eyestrain from the appearance (only headaches from results not meeting expectations). Brightness is okay to use in a well-lighted office environment but gets a bit dim outdoors in the shade (such as a QRP outing?). I don't know if they are made any more, couldn't get through the Agilent-HP site to find them. Someone makes those little LED numeric arrays now, used in hand-carried frequency counters. A PIC would strobe segments and the program could be adjusted to optimize the on-time duty cycle for a particular segment. In using unmagnified LEDs, the average segment current is around 5 mA minimum for sufficient brightness but that is variable depending on the molded-in filtering for various colors (attenuates brightness). Strobing would require higher peak currents. Len Anderson retired (from regular hours) electronic engineer person |
Hey! I think I have some of those. Since I'm never going to use them, I
suppose I could part with them. But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. "Avery Fineman" wrote in message ... In article , "Dale Parfitt" writes: Anyone know of a PIC based frequency counter using the low current 7 segment readouts as in the Elecraft KX-1? Size, durability and I drain are the important factors here- LCD displays are not an option. A problem there is finding an LED numeric display with low current per segment or a driver capable of higher peak current for sequential strobing of an array of LEDs. The only thing that I could recommend is the miniature LED array with integral magnifying lens and filter that HP made for their first scientific calculator, the HP-35. In the HP 1979 Optoelectronic databook, the 5082-7200 series and 5082-7400 series have varying numeric character assemblies from 2 to 16 digits. The 5082-7240 is an 8-digit assembly "capable of being driven by MOS circuits" (according to catalog text, apparently in reference to calculator use). Average per segment current is about 0.5 mA and peak current (for strobing array) is 5.0 mA. The character height is 2.59mm by 1.52mm wide but magnified by the integral plastic lens. I've stared at that HP-35 calculator display long enough without eyestrain from the appearance (only headaches from results not meeting expectations). Brightness is okay to use in a well-lighted office environment but gets a bit dim outdoors in the shade (such as a QRP outing?). I don't know if they are made any more, couldn't get through the Agilent-HP site to find them. Someone makes those little LED numeric arrays now, used in hand-carried frequency counters. A PIC would strobe segments and the program could be adjusted to optimize the on-time duty cycle for a particular segment. In using unmagnified LEDs, the average segment current is around 5 mA minimum for sufficient brightness but that is variable depending on the molded-in filtering for various colors (attenuates brightness). Strobing would require higher peak currents. Len Anderson retired (from regular hours) electronic engineer person |
"Tim Wescott" wrote in message
... But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. I was wondering that myself. It's a whole bunch lower power than LEDs, which seemed to be a requirement, and the circuitry is a pile simpler. The one requirement he did have was "durability" that maybe you could argue LEDs had a leg up on. Well, maybe with those teeny LED displays you could keep the size smaller than an LCD, but I suspect you would more than make up for it in drive circuitry, unless maybe he's thinking surface mount. Oh, and driving an LCD is a piece of cake from a PIC. ... |
"Tim Wescott" wrote in message
... But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. I was wondering that myself. It's a whole bunch lower power than LEDs, which seemed to be a requirement, and the circuitry is a pile simpler. The one requirement he did have was "durability" that maybe you could argue LEDs had a leg up on. Well, maybe with those teeny LED displays you could keep the size smaller than an LCD, but I suspect you would more than make up for it in drive circuitry, unless maybe he's thinking surface mount. Oh, and driving an LCD is a piece of cake from a PIC. ... |
"xpyttl" wrote in message ... "Tim Wescott" wrote in message ... But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. I was wondering that myself. It's a whole bunch lower power than LEDs, which seemed to be a requirement, and the circuitry is a pile simpler. The one requirement he did have was "durability" that maybe you could argue LEDs had a leg up on. Well, maybe with those teeny LED displays you could keep the size smaller than an LCD, but I suspect you would more than make up for it in drive circuitry, unless maybe he's thinking surface mount. Oh, and driving an LCD is a piece of cake from a PIC. ..I appreciate all the comments. The glass cases of the LCD- aside from being large, is a bit fragile. This is going in a very small trail ready radio- that may have to survive falls from 3000' rock cliffs. Already lost an LCD that way. Dale W4OP |
"xpyttl" wrote in message ... "Tim Wescott" wrote in message ... But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. I was wondering that myself. It's a whole bunch lower power than LEDs, which seemed to be a requirement, and the circuitry is a pile simpler. The one requirement he did have was "durability" that maybe you could argue LEDs had a leg up on. Well, maybe with those teeny LED displays you could keep the size smaller than an LCD, but I suspect you would more than make up for it in drive circuitry, unless maybe he's thinking surface mount. Oh, and driving an LCD is a piece of cake from a PIC. ..I appreciate all the comments. The glass cases of the LCD- aside from being large, is a bit fragile. This is going in a very small trail ready radio- that may have to survive falls from 3000' rock cliffs. Already lost an LCD that way. Dale W4OP |
In article , "Tim Wescott"
writes: Hey! I think I have some of those. Since I'm never going to use them, I suppose I could part with them. But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. You are asking the wrong person. I was responding to the person saying "LCDs are not an option." An LCD display assembly can most certainly be "driven" (input the ASCII code for the character) from a PIC. That is how nearly all of the little wattmeters and frequency counters are arranged. Actual DRIVE for an LCD takes a different waveform for most LCD panels. Some are 2-level, others 3-level in their waveform voltages. Research the LCD display alone, without the local memory and scan-drive hardware. That part is not as straightforward as it looks. A PIC PROGRAM normally scans through an internal register content and outputs based on that. Usually there is a small conversion operation to change the code from 4-bit numeric to 8-bit ASCII. That scanning-and-outputting part of the program can easily be changed (if you know how to write with the free PIC development program) to "strobe" an LED array, segments versus character position. If you don't know how to change an already burned-in PIC, then you must have some sort of outboard local memory to hold 4-bit chunks of numeric data...or convert from 8-bit ASCII to two 4-bit BCD in order to drive a 7-bar segment decoder-driver that CAN drive a numeric LED. That requires more ICs, one decoder-driver per numeral. Average power to light the LED is about the same for any given brightness whether it is driven on a DC basis or strobed segment v. numeral. NONE of the above is "trivial" nor any sort of "cake" if you've never worked with microcontrollers or their development systems before. Almost ANYTHING "doable" can be done but development time and resulting learning curves are hard to fund at the home hobbyist level. For example, I've been working on inventing anti-gravity. Something keeps holding the project down ... Len Anderson retired (from regular hours) electronic engineer person |
In article , "Tim Wescott"
writes: Hey! I think I have some of those. Since I'm never going to use them, I suppose I could part with them. But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. You are asking the wrong person. I was responding to the person saying "LCDs are not an option." An LCD display assembly can most certainly be "driven" (input the ASCII code for the character) from a PIC. That is how nearly all of the little wattmeters and frequency counters are arranged. Actual DRIVE for an LCD takes a different waveform for most LCD panels. Some are 2-level, others 3-level in their waveform voltages. Research the LCD display alone, without the local memory and scan-drive hardware. That part is not as straightforward as it looks. A PIC PROGRAM normally scans through an internal register content and outputs based on that. Usually there is a small conversion operation to change the code from 4-bit numeric to 8-bit ASCII. That scanning-and-outputting part of the program can easily be changed (if you know how to write with the free PIC development program) to "strobe" an LED array, segments versus character position. If you don't know how to change an already burned-in PIC, then you must have some sort of outboard local memory to hold 4-bit chunks of numeric data...or convert from 8-bit ASCII to two 4-bit BCD in order to drive a 7-bar segment decoder-driver that CAN drive a numeric LED. That requires more ICs, one decoder-driver per numeral. Average power to light the LED is about the same for any given brightness whether it is driven on a DC basis or strobed segment v. numeral. NONE of the above is "trivial" nor any sort of "cake" if you've never worked with microcontrollers or their development systems before. Almost ANYTHING "doable" can be done but development time and resulting learning curves are hard to fund at the home hobbyist level. For example, I've been working on inventing anti-gravity. Something keeps holding the project down ... Len Anderson retired (from regular hours) electronic engineer person |
Dale Parfitt wrote:
..I appreciate all the comments. The glass cases of the LCD- aside from being large, is a bit fragile. This is going in a very small trail ready radio- that may have to survive falls from 3000' rock cliffs. Already lost an LCD that way. Dale W4OP Wow I suspect not much would survive that sort of fall My counter at http://members.iinet.net.au/~richardh/VK6BRO.htm takes less than 10 mA The LCD module is probably as rugged as a LED setup, particularly if you have to mount individual displays and drivers opn a board Unfortunately I have sold all the current boards but the software and circuitry is there. It uses a AVR rather than a PIC Richard |
Dale Parfitt wrote:
..I appreciate all the comments. The glass cases of the LCD- aside from being large, is a bit fragile. This is going in a very small trail ready radio- that may have to survive falls from 3000' rock cliffs. Already lost an LCD that way. Dale W4OP Wow I suspect not much would survive that sort of fall My counter at http://members.iinet.net.au/~richardh/VK6BRO.htm takes less than 10 mA The LCD module is probably as rugged as a LED setup, particularly if you have to mount individual displays and drivers opn a board Unfortunately I have sold all the current boards but the software and circuitry is there. It uses a AVR rather than a PIC Richard |
At first I thought you wanted a counter, but it sounds more like a frequency
display for a rig is what you are looking for. If you're madly in love with LEDs, you may want something like that one digit counter that I think was in QST a few years back. Understand that LEDs are current hungry and require relatively complex support circuitry compared to LCDs. You can reduce both of these by cutting down the number of digits. You can also add some complexity, either in software or circuitry, to help with the current drain, but finding something that will likely work with your radio is improbable .. to get the combination you are going to have to do some of the design work yourself. You will also be challenged in trading off the current for brightness. I suspect (can't say I know for sure) that making an LED display work at low current at a brightness level you could use outdoors in the daytime is going to be something of a problem. That being said, what about something like Dave Fifield's AFA or Dave Benson's Freq-Mite? This gets you way smaller and lighter than your LEDs, and certainly no less durable. And the current consumption will be orders of magnitude less than even the most carefully implemented LEDs. You don't get the warm, red glow, but you get the frequency in a fraction of the size/weight/current. And for twenty bucks you avoid the whole design/parts procurement exercise. ... "Dale Parfitt" wrote in message ... "xpyttl" wrote in message ... "Tim Wescott" wrote in message ... But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. I was wondering that myself. It's a whole bunch lower power than LEDs, which seemed to be a requirement, and the circuitry is a pile simpler. The one requirement he did have was "durability" that maybe you could argue LEDs had a leg up on. Well, maybe with those teeny LED displays you could keep the size smaller than an LCD, but I suspect you would more than make up for it in drive circuitry, unless maybe he's thinking surface mount. Oh, and driving an LCD is a piece of cake from a PIC. ..I appreciate all the comments. The glass cases of the LCD- aside from being large, is a bit fragile. This is going in a very small trail ready radio- that may have to survive falls from 3000' rock cliffs. Already lost an LCD that way. Dale W4OP |
At first I thought you wanted a counter, but it sounds more like a frequency
display for a rig is what you are looking for. If you're madly in love with LEDs, you may want something like that one digit counter that I think was in QST a few years back. Understand that LEDs are current hungry and require relatively complex support circuitry compared to LCDs. You can reduce both of these by cutting down the number of digits. You can also add some complexity, either in software or circuitry, to help with the current drain, but finding something that will likely work with your radio is improbable .. to get the combination you are going to have to do some of the design work yourself. You will also be challenged in trading off the current for brightness. I suspect (can't say I know for sure) that making an LED display work at low current at a brightness level you could use outdoors in the daytime is going to be something of a problem. That being said, what about something like Dave Fifield's AFA or Dave Benson's Freq-Mite? This gets you way smaller and lighter than your LEDs, and certainly no less durable. And the current consumption will be orders of magnitude less than even the most carefully implemented LEDs. You don't get the warm, red glow, but you get the frequency in a fraction of the size/weight/current. And for twenty bucks you avoid the whole design/parts procurement exercise. ... "Dale Parfitt" wrote in message ... "xpyttl" wrote in message ... "Tim Wescott" wrote in message ... But first the obligitory assesment of assumptions: Why are LCD displays not an option? Could you drive an LCD from your PIC? I've seen info on this from the LCD manufacturers; it looks quite doable from a PIC. I was wondering that myself. It's a whole bunch lower power than LEDs, which seemed to be a requirement, and the circuitry is a pile simpler. The one requirement he did have was "durability" that maybe you could argue LEDs had a leg up on. Well, maybe with those teeny LED displays you could keep the size smaller than an LCD, but I suspect you would more than make up for it in drive circuitry, unless maybe he's thinking surface mount. Oh, and driving an LCD is a piece of cake from a PIC. ..I appreciate all the comments. The glass cases of the LCD- aside from being large, is a bit fragile. This is going in a very small trail ready radio- that may have to survive falls from 3000' rock cliffs. Already lost an LCD that way. Dale W4OP |
"Avery Fineman" wrote in message
... In article , "Tim Wescott" writes: NONE of the above is "trivial" nor any sort of "cake" if you've never worked with microcontrollers or their development systems before. Almost ANYTHING "doable" can be done but development time and resulting learning curves are hard to fund at the home hobbyist level. Au contraire! Well, I suppose if you are scared to death of solid state electronics and computers, then perhaps it's really hard. But in this day and age a huge fraction, bordering on most, amateur radio projects involve some sort of microcontroller. This isn't some comspiracy, they make the whole project simpler, less expensive, and more flexible. Granted, there is a learning curve if you've never done it before, but I would expect that someone who wasn't totally terrified could learn enough to make the sorts of changes he might need to an off the shelf project, build the programming hardware, and get the project working in less time/effort/money than simply getting a reasonable number of LED digits wired and driven! ... |
"Avery Fineman" wrote in message
... In article , "Tim Wescott" writes: NONE of the above is "trivial" nor any sort of "cake" if you've never worked with microcontrollers or their development systems before. Almost ANYTHING "doable" can be done but development time and resulting learning curves are hard to fund at the home hobbyist level. Au contraire! Well, I suppose if you are scared to death of solid state electronics and computers, then perhaps it's really hard. But in this day and age a huge fraction, bordering on most, amateur radio projects involve some sort of microcontroller. This isn't some comspiracy, they make the whole project simpler, less expensive, and more flexible. Granted, there is a learning curve if you've never done it before, but I would expect that someone who wasn't totally terrified could learn enough to make the sorts of changes he might need to an off the shelf project, build the programming hardware, and get the project working in less time/effort/money than simply getting a reasonable number of LED digits wired and driven! ... |
In article , "xpyttl"
writes: "Avery Fineman" wrote in message ... In article , "Tim Wescott" writes: NONE of the above is "trivial" nor any sort of "cake" if you've never worked with microcontrollers or their development systems before. Almost ANYTHING "doable" can be done but development time and resulting learning curves are hard to fund at the home hobbyist level. Au contraire! Well, I suppose if you are scared to death of solid state electronics and computers, then perhaps it's really hard. Not I. Made my living, paid the bills for over four decades plus using, designing with semiconductors. :-) Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, of outlining a sequence of events governed by decision points of states, of (at least) being familiar with instructions/commands recognized by the micro. While the PIC development program is free, the ability to use the program is not automatic in download. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. Having done that sort of thing primarily for hobby purposes for over two decades, I find it both fun and fascinating in total control of a micro's actions. My only complaint there is that there is no standardization of instructions between manufacturers...the "dialects" require small learning curves each time there is a switch of micro families. The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. It's hard to beat the AADE unit (available for any conversion scheme, direct- to triple-conversion) for applying a relatively cheap ready-built to a frequency indicator. www.aade.com But in this day and age a huge fraction, bordering on most, amateur radio projects involve some sort of microcontroller. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since those require many pages of expensive paper (which needs advertising space sold to make it "cheap"). It isn't immediately flashy and the program writers don't always include Comments in source code sufficient to make the program flow clear at first reading. Ready-built, off-the-shelf amateur radio equipment DOES use one or more microcontrollers internally. You cannot truly qualify that "most" hobby projects use them. :-) This isn't some comspiracy, they make the whole project simpler, less expensive, and more flexible. Totally agreed. However, in fairness, use of a microcontroller in a ham project is NOT traditional analog circuitry (that some old-timers insist is the "only" kind of "radio"). It does NOT exemplify the mass of mechanical structures used in 3 and 4 decade old project pictures looked at many times in old handbooks...looked at in emotional awe and wonderment. Microcontrollers are NOT traditional components and have functions unrelated to physical mechanics that they often replace. Different. Minds have to adapt to NEW ways to do things. Granted, there is a learning curve if you've never done it before, but I would expect that someone who wasn't totally terrified could learn enough to make the sorts of changes he might need to an off the shelf project, build the programming hardware, and get the project working in less time/effort/money than simply getting a reasonable number of LED digits wired and driven! Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) In a remote way, yes. Unknowns are not a "terror" to everyone. They should be just things unknown that must be learned in order to apply them. That takes some skull sweat at becoming familiar and such study takes TIME. Such learning time seldom provides immediate solutions to a present project but it has incalculable worth in being able to apply the micro techniques to all sorts of future problems. Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. I'm working on inventing anti-gravity...but something's holding the project down. Len Anderson retired (from regular hours) electronic engineer person |
In article , "xpyttl"
writes: "Avery Fineman" wrote in message ... In article , "Tim Wescott" writes: NONE of the above is "trivial" nor any sort of "cake" if you've never worked with microcontrollers or their development systems before. Almost ANYTHING "doable" can be done but development time and resulting learning curves are hard to fund at the home hobbyist level. Au contraire! Well, I suppose if you are scared to death of solid state electronics and computers, then perhaps it's really hard. Not I. Made my living, paid the bills for over four decades plus using, designing with semiconductors. :-) Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, of outlining a sequence of events governed by decision points of states, of (at least) being familiar with instructions/commands recognized by the micro. While the PIC development program is free, the ability to use the program is not automatic in download. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. Having done that sort of thing primarily for hobby purposes for over two decades, I find it both fun and fascinating in total control of a micro's actions. My only complaint there is that there is no standardization of instructions between manufacturers...the "dialects" require small learning curves each time there is a switch of micro families. The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. It's hard to beat the AADE unit (available for any conversion scheme, direct- to triple-conversion) for applying a relatively cheap ready-built to a frequency indicator. www.aade.com But in this day and age a huge fraction, bordering on most, amateur radio projects involve some sort of microcontroller. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since those require many pages of expensive paper (which needs advertising space sold to make it "cheap"). It isn't immediately flashy and the program writers don't always include Comments in source code sufficient to make the program flow clear at first reading. Ready-built, off-the-shelf amateur radio equipment DOES use one or more microcontrollers internally. You cannot truly qualify that "most" hobby projects use them. :-) This isn't some comspiracy, they make the whole project simpler, less expensive, and more flexible. Totally agreed. However, in fairness, use of a microcontroller in a ham project is NOT traditional analog circuitry (that some old-timers insist is the "only" kind of "radio"). It does NOT exemplify the mass of mechanical structures used in 3 and 4 decade old project pictures looked at many times in old handbooks...looked at in emotional awe and wonderment. Microcontrollers are NOT traditional components and have functions unrelated to physical mechanics that they often replace. Different. Minds have to adapt to NEW ways to do things. Granted, there is a learning curve if you've never done it before, but I would expect that someone who wasn't totally terrified could learn enough to make the sorts of changes he might need to an off the shelf project, build the programming hardware, and get the project working in less time/effort/money than simply getting a reasonable number of LED digits wired and driven! Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) In a remote way, yes. Unknowns are not a "terror" to everyone. They should be just things unknown that must be learned in order to apply them. That takes some skull sweat at becoming familiar and such study takes TIME. Such learning time seldom provides immediate solutions to a present project but it has incalculable worth in being able to apply the micro techniques to all sorts of future problems. Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. I'm working on inventing anti-gravity...but something's holding the project down. Len Anderson retired (from regular hours) electronic engineer person |
"Avery Fineman" wrote in message
... Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, I have to admit, I do try to discourage people, perhaps with a little too much fervor, from being afraid of using micros. They are a lot simpler than most folks realize. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. And this is different from designing with discrete logic how? The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. Yes, but it has become clear that the original poster had a rather specific application that he is not going to be able to get off the shelf for a reasonable price. He will need to take an existing design and alter it, or roll his own. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since No, but they always provide links to the code online. Have you opened a copy of QST lately? Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) Absolutely g Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. Certainly, I don't think there is anything wrong with using LEDs. But the original poster was looking for something low current - not a real strong suit for LEDs. He was looking for something simple. LEDs are a problem there, too, because of the drive circuitry. If he is going to count frequency, within a project that he can get done this year, he is going to use a microcontroller of some ilk. Building a frequency counter from discrete parts is a huge job. And then, he wants it small. Again, the whole discrete logic thing makes that nearly impossible for the hobbyist. To top is off, he wants low current. Yes, absolutely doable with LEDs but with a huge added cost in complexity, especially if you decide up front no micros. Frequency counters used to cost thousands of dollars. Today they are orders of magnitude cheaper because they are orders of magnitude simpler. And they are orders of magnitude simpler because virtually all the circuitry is in the micro. I just took a quick look at my counter - under 20 parts. Go to LEDs and you probably triple that. But take out the micro and you are talking about hundreds of parts. Perhaps I am downplaying the difficulty in learning how to apply micros, but you are certainly downplaying the difficulty of not applying them in this context. It sounds like maybe you had some sort of anlog frequency display in mind, which I don't quite picture. Might be a cool thing, though. ... |
"Avery Fineman" wrote in message
... Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, I have to admit, I do try to discourage people, perhaps with a little too much fervor, from being afraid of using micros. They are a lot simpler than most folks realize. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. And this is different from designing with discrete logic how? The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. Yes, but it has become clear that the original poster had a rather specific application that he is not going to be able to get off the shelf for a reasonable price. He will need to take an existing design and alter it, or roll his own. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since No, but they always provide links to the code online. Have you opened a copy of QST lately? Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) Absolutely g Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. Certainly, I don't think there is anything wrong with using LEDs. But the original poster was looking for something low current - not a real strong suit for LEDs. He was looking for something simple. LEDs are a problem there, too, because of the drive circuitry. If he is going to count frequency, within a project that he can get done this year, he is going to use a microcontroller of some ilk. Building a frequency counter from discrete parts is a huge job. And then, he wants it small. Again, the whole discrete logic thing makes that nearly impossible for the hobbyist. To top is off, he wants low current. Yes, absolutely doable with LEDs but with a huge added cost in complexity, especially if you decide up front no micros. Frequency counters used to cost thousands of dollars. Today they are orders of magnitude cheaper because they are orders of magnitude simpler. And they are orders of magnitude simpler because virtually all the circuitry is in the micro. I just took a quick look at my counter - under 20 parts. Go to LEDs and you probably triple that. But take out the micro and you are talking about hundreds of parts. Perhaps I am downplaying the difficulty in learning how to apply micros, but you are certainly downplaying the difficulty of not applying them in this context. It sounds like maybe you had some sort of anlog frequency display in mind, which I don't quite picture. Might be a cool thing, though. ... |
If you buy a preprogrammed chip, you dont have to do any programming of
your own. Richard xpyttl wrote: "Avery Fineman" wrote in message ... Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, I have to admit, I do try to discourage people, perhaps with a little too much fervor, from being afraid of using micros. They are a lot simpler than most folks realize. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. And this is different from designing with discrete logic how? The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. Yes, but it has become clear that the original poster had a rather specific application that he is not going to be able to get off the shelf for a reasonable price. He will need to take an existing design and alter it, or roll his own. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since No, but they always provide links to the code online. Have you opened a copy of QST lately? Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) Absolutely g Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. Certainly, I don't think there is anything wrong with using LEDs. But the original poster was looking for something low current - not a real strong suit for LEDs. He was looking for something simple. LEDs are a problem there, too, because of the drive circuitry. If he is going to count frequency, within a project that he can get done this year, he is going to use a microcontroller of some ilk. Building a frequency counter from discrete parts is a huge job. And then, he wants it small. Again, the whole discrete logic thing makes that nearly impossible for the hobbyist. To top is off, he wants low current. Yes, absolutely doable with LEDs but with a huge added cost in complexity, especially if you decide up front no micros. Frequency counters used to cost thousands of dollars. Today they are orders of magnitude cheaper because they are orders of magnitude simpler. And they are orders of magnitude simpler because virtually all the circuitry is in the micro. I just took a quick look at my counter - under 20 parts. Go to LEDs and you probably triple that. But take out the micro and you are talking about hundreds of parts. Perhaps I am downplaying the difficulty in learning how to apply micros, but you are certainly downplaying the difficulty of not applying them in this context. It sounds like maybe you had some sort of anlog frequency display in mind, which I don't quite picture. Might be a cool thing, though. .. |
If you buy a preprogrammed chip, you dont have to do any programming of
your own. Richard xpyttl wrote: "Avery Fineman" wrote in message ... Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, I have to admit, I do try to discourage people, perhaps with a little too much fervor, from being afraid of using micros. They are a lot simpler than most folks realize. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. And this is different from designing with discrete logic how? The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. Yes, but it has become clear that the original poster had a rather specific application that he is not going to be able to get off the shelf for a reasonable price. He will need to take an existing design and alter it, or roll his own. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since No, but they always provide links to the code online. Have you opened a copy of QST lately? Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) Absolutely g Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. Certainly, I don't think there is anything wrong with using LEDs. But the original poster was looking for something low current - not a real strong suit for LEDs. He was looking for something simple. LEDs are a problem there, too, because of the drive circuitry. If he is going to count frequency, within a project that he can get done this year, he is going to use a microcontroller of some ilk. Building a frequency counter from discrete parts is a huge job. And then, he wants it small. Again, the whole discrete logic thing makes that nearly impossible for the hobbyist. To top is off, he wants low current. Yes, absolutely doable with LEDs but with a huge added cost in complexity, especially if you decide up front no micros. Frequency counters used to cost thousands of dollars. Today they are orders of magnitude cheaper because they are orders of magnitude simpler. And they are orders of magnitude simpler because virtually all the circuitry is in the micro. I just took a quick look at my counter - under 20 parts. Go to LEDs and you probably triple that. But take out the micro and you are talking about hundreds of parts. Perhaps I am downplaying the difficulty in learning how to apply micros, but you are certainly downplaying the difficulty of not applying them in this context. It sounds like maybe you had some sort of anlog frequency display in mind, which I don't quite picture. Might be a cool thing, though. .. |
In article , "xpyttl"
writes: "Avery Fineman" wrote in message ... Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, I have to admit, I do try to discourage people, perhaps with a little too much fervor, from being afraid of using micros. They are a lot simpler than most folks realize. A PIC in a DIP is physically no different than any other DIP. Plug it in or solder it in. No problem. What matters is the programming inside that PIC (or any other brand microcontroller). That program's development is done outside the DIP, then loaded into it. THAT is where the difference is. It is more like a microprocessor (a microcontroller IS a microprocessor plus some other circuits and functions) but the PIC is designed with a small number of instructions. Far easier to memorize than the full set for an Intel micro in a PC. Note: The memorization DOES occur when starting to program or flow-charting someone else's program, helps a great deal in reducing constant look-up to the instruction chart. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. And this is different from designing with discrete logic how? Do you want the whole book on that or just a synopsis? :-) Hard-wired digital logic doesn't quite have "decision diamonds" but some are close to that. I've programmed several micros, beginning with an HP 9100 calculator, going on to Motorola 6800s, then to MOSTEK 6502s (in the Apple ][), Intel 8051s, the Intel family in the PCs (through MASM), and finally the PIC 16Fs which I've just started in on. The 6502 had a nice flag in the Carry of the accumulator that Apple's DOS 3.3 made extensive use of...but there isn't an equivalent discrete digital logic equivalent for that function ability. Digital logic is fairly straightforward in design and application where the main constraints are t_pd and fan-out/fan-in. Go for the states and everything happens, no "program development" needed. One CAN flow-chart some of it, or analyze states (especially so for a state machine with a PLD) but most of it goes down on paper, can be analyzed right off and applied. No program development needed. The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. Yes, but it has become clear that the original poster had a rather specific application that he is not going to be able to get off the shelf for a reasonable price. He will need to take an existing design and alter it, or roll his own. So? The original request was - specifically - NOT to use an LCD. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since No, but they always provide links to the code online. Have you opened a copy of QST lately? Not since about two weeks ago. Just glancing through it. :-) Have you "opened a Dr. Dobbs" recently? Or the PIC website to get appnotes? [very slow for some reason compared to other sites] How about a couple dozen websites with some ingenious applications, including frequency counter applications not mentioned in here? Have you opened a digital logic databook recently? I've been source coding since the 70s and cannot immediately glean meaning from a large listing of machine instructions. I don't know of any professional programmer who can do that with unfamiliar source. Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) Absolutely g Electrons aren't into human emotionalism or that "can-do-anything" stuff. One works by THEIR rules or they won't cooperate. Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. Certainly, I don't think there is anything wrong with using LEDs. But the original poster was looking for something low current - not a real strong suit for LEDs. He was looking for something simple. No. He was looking for a display NOT an LCD. As I said in my reply, LEDs draw far more current than LCDs, and that will include large LCD display assemblies with their internal local memory and screen driver circuitry. LEDs are a problem there, too, because of the drive circuitry. Nonsense. A CD4511 is still off the shelf, BCD to 7-segment, latch and decoder-driver. Just add series resistors for segments and play. A buck apiece in single quantities. No programming. If he is going to count frequency, within a project that he can get done this year, he is going to use a microcontroller of some ilk. Building a frequency counter from discrete parts is a huge job. From discrete transistors, yes. :-) From off-the-shelf ICs, no. I did all the design and building of my own "discrete" frequency counter and time interval meter using RTL back in 1967...while busy working at a place with a long commute. I'm glad RTL got discontinued. :-) Since then I've done a small CMOS (4-digit) counter and am finishing a "discrete" 74F and 74LS (TTL) 7-digit counter with adjustable preset capability and up-down counting (!!).. Step-and-repeat for all those digits. LED display. Why? I wanted specifically a display I could see out of the corner of my eye (therefore bright) while concentrating on work right in front of me. It is a workshop instrument, not a QRP thing to take up a mountain. If I wanted such I would bring up the PIC developement program, sketch flow charts, write source code (with lots and lots of comments to tell me what I was doing in the future)... and add more very-portable-rig functions and use a small LCD display to save on battery drain. And then, he wants it small. Again, the whole discrete logic thing makes that nearly impossible for the hobbyist. Why are you emphasizing all that "discrete logic" thing? Extremely easy to use that from low-cost off-the-shelf items if one is familiar with the available logic packages. Legacy parts. Old, some have already been dropped from production. To top is off, he wants low current. Yes, absolutely doable with LEDs but with a huge added cost in complexity, especially if you decide up front no micros. No. Using LEDs is NOT "low current." Not even for the first scientific calculator. The HP-35 may have approached a practical limit on LED numerics at _minimum_ current but it doesn't compare with LCDs except maybe those LCDs with bright backlighting. Who was mandating "no micros?" Not me. The scheme to use an internal counting register as an initial accumulator is fairly recent (about within the last 6 years). "Discrete" logic (very discrete, including two- transistor flip-flops) counters go back to before 1960. Frequency counters used to cost thousands of dollars. My 6-digit RTL counter, using all-new parts off-the-shelf, cost less than $300 in 1967. Included many extra parts, some still in the workshop parts collection, unused. Had oven-controlled 10 MHz timebase crystal. Today my timebase standard is a TCXO which will become a TCVXO when the 60 KHz phase-locker receiver-controller is completed. The display is LED only because that is _easy_ to implement, a no-strain thing and it is bright. Yes, brightness takes current but this is a lab instrument and not battery powered. The total parts cost is less than $500 for both halves in 2003. Absolutely NO programming required. Yes, I do know the cost of manufactured instruments. Was calibrating HP 524 counters in 1960 (B model was all vacuum state, maximum count frequency of 10 MHz, neon "thermometer" numeric display, weight excellent for body building). Today they are orders of magnitude cheaper because they are orders of magnitude simpler. And they are orders of magnitude simpler because virtually all the circuitry is in the micro. I just took a quick look at my counter - under 20 parts. Go to LEDs and you probably triple that. But take out the micro and you are talking about hundreds of parts. A 16F84 or 16F71 as a frequency counter needs only a Schmitt trigger input to shape up the arbitrary waveform, maybe a "discrete" comparator IC if one is fussy, to count directly to 30 MHz. Going higher in frequency needs an extra "discrete" IC, a prescaler. That and an LCD assembly, one of many kinds available. The stuff NOT in "discrete hardware" is the PROGRAM. Do that one right and it is a fine little instrument. Do it wrong and there is a struggle to right it that may take hours and days, including bench measurement. Using others' source code is fine, much much easier. Provided the LCD assembly is the same as the authors', but if you have an LCD with a different sequence of data, of format, then it is back to the development program again. Perhaps I am downplaying the difficulty in learning how to apply micros, but you are certainly downplaying the difficulty of not applying them in this context. I thought I gave a reasonable reply the first time. Looked at several options. Were you gathering sticks for an Internet burning at the stake? :-) When giving suggestions it is better to cover the wide range of possibilities first rather than second-guess another's depth of knowledge, experience, or desire. It sounds like maybe you had some sort of anlog frequency display in mind, which I don't quite picture. Might be a cool thing, though. I've been using displays of many kinds in a long time, starting with gas numerics (Amperex Bi-Quinary tubes, like a Burroughs Nixie but 2 x 5, not 1 x 10)...and going through all the others except plasma dot matrix panels. If it's an LCD and there's a circuit driver IC for it, I will use those first. The weird waveforms have already been worked out and the ICs packaged. No driver IC and I start looking at other ways to display information. I don't know everything but I've been around a while and had hands-on in many things. When you say "discrete" active devices, try to put that in context of individual transistors. Or tubes. I've done both. Never again, I hope. You ought to call TTL and functional-equivalent CMOS logic as either SSI, MSI, or LSI (which they are) not "discrete." Done those in more than counter circuitry. Microprocessors and microcontrollers fall under the VLSI category. Microcontrollers are wonderful devices for making certain things with very low hardware count and near-minimal power demand. But, their application in special things requires PROGRAMMING. That isn't in the hardware. Such MUST be there. It CAN be learned. Some, like me, find programming fun. Others do not. I do not find having to learn new instruction sets for other micro families to be fun. Nuisance. Was there anything else? :-) Len Anderson retired (from regular hours) electronic engineer person |
In article , "xpyttl"
writes: "Avery Fineman" wrote in message ... Try a dose of realistic thinking in terms of hardware, based on the time available for hobby projects. Time. That most precious of all personal commodities. Programming a microcontroller is not trivial. It requires a new skill, I have to admit, I do try to discourage people, perhaps with a little too much fervor, from being afraid of using micros. They are a lot simpler than most folks realize. A PIC in a DIP is physically no different than any other DIP. Plug it in or solder it in. No problem. What matters is the programming inside that PIC (or any other brand microcontroller). That program's development is done outside the DIP, then loaded into it. THAT is where the difference is. It is more like a microprocessor (a microcontroller IS a microprocessor plus some other circuits and functions) but the PIC is designed with a small number of instructions. Far easier to memorize than the full set for an Intel micro in a PC. Note: The memorization DOES occur when starting to program or flow-charting someone else's program, helps a great deal in reducing constant look-up to the instruction chart. One MUST become familiar with "Assembler level" programming, of including every single sequential command and decision point needed by the program application. And this is different from designing with discrete logic how? Do you want the whole book on that or just a synopsis? :-) Hard-wired digital logic doesn't quite have "decision diamonds" but some are close to that. I've programmed several micros, beginning with an HP 9100 calculator, going on to Motorola 6800s, then to MOSTEK 6502s (in the Apple ][), Intel 8051s, the Intel family in the PCs (through MASM), and finally the PIC 16Fs which I've just started in on. The 6502 had a nice flag in the Carry of the accumulator that Apple's DOS 3.3 made extensive use of...but there isn't an equivalent discrete digital logic equivalent for that function ability. Digital logic is fairly straightforward in design and application where the main constraints are t_pd and fan-out/fan-in. Go for the states and everything happens, no "program development" needed. One CAN flow-chart some of it, or analyze states (especially so for a state machine with a PLD) but most of it goes down on paper, can be analyzed right off and applied. No program development needed. The most convenient was to apply a microprocessor or micro- controller is to get one with the program already burned in. Saves an enormous amount of development time...but does not do any good for personal programming experience, only in the installation of the micro. Yes, but it has become clear that the original poster had a rather specific application that he is not going to be able to get off the shelf for a reasonable price. He will need to take an existing design and alter it, or roll his own. So? The original request was - specifically - NOT to use an LCD. Yes and no. :-) That depends on the source of information for the project. Magazines don't like to include pages of a PIC program since No, but they always provide links to the code online. Have you opened a copy of QST lately? Not since about two weeks ago. Just glancing through it. :-) Have you "opened a Dr. Dobbs" recently? Or the PIC website to get appnotes? [very slow for some reason compared to other sites] How about a couple dozen websites with some ingenious applications, including frequency counter applications not mentioned in here? Have you opened a digital logic databook recently? I've been source coding since the 70s and cannot immediately glean meaning from a large listing of machine instructions. I don't know of any professional programmer who can do that with unfamiliar source. Of course. :-) The pep-rally over-confidence syndrome...one can do anything with a "positive outlook"...immediately...no problems at all, right? :-) Absolutely g Electrons aren't into human emotionalism or that "can-do-anything" stuff. One works by THEIR rules or they won't cooperate. Why bash anyone for wanting to use LEDs instead of LCDs? There are advantages to each kind of display. For a personal project, I would think that it is up to the individual to determine individual desires. Is there something "wrong" with individualism? I think not. Certainly, I don't think there is anything wrong with using LEDs. But the original poster was looking for something low current - not a real strong suit for LEDs. He was looking for something simple. No. He was looking for a display NOT an LCD. As I said in my reply, LEDs draw far more current than LCDs, and that will include large LCD display assemblies with their internal local memory and screen driver circuitry. LEDs are a problem there, too, because of the drive circuitry. Nonsense. A CD4511 is still off the shelf, BCD to 7-segment, latch and decoder-driver. Just add series resistors for segments and play. A buck apiece in single quantities. No programming. If he is going to count frequency, within a project that he can get done this year, he is going to use a microcontroller of some ilk. Building a frequency counter from discrete parts is a huge job. From discrete transistors, yes. :-) From off-the-shelf ICs, no. I did all the design and building of my own "discrete" frequency counter and time interval meter using RTL back in 1967...while busy working at a place with a long commute. I'm glad RTL got discontinued. :-) Since then I've done a small CMOS (4-digit) counter and am finishing a "discrete" 74F and 74LS (TTL) 7-digit counter with adjustable preset capability and up-down counting (!!).. Step-and-repeat for all those digits. LED display. Why? I wanted specifically a display I could see out of the corner of my eye (therefore bright) while concentrating on work right in front of me. It is a workshop instrument, not a QRP thing to take up a mountain. If I wanted such I would bring up the PIC developement program, sketch flow charts, write source code (with lots and lots of comments to tell me what I was doing in the future)... and add more very-portable-rig functions and use a small LCD display to save on battery drain. And then, he wants it small. Again, the whole discrete logic thing makes that nearly impossible for the hobbyist. Why are you emphasizing all that "discrete logic" thing? Extremely easy to use that from low-cost off-the-shelf items if one is familiar with the available logic packages. Legacy parts. Old, some have already been dropped from production. To top is off, he wants low current. Yes, absolutely doable with LEDs but with a huge added cost in complexity, especially if you decide up front no micros. No. Using LEDs is NOT "low current." Not even for the first scientific calculator. The HP-35 may have approached a practical limit on LED numerics at _minimum_ current but it doesn't compare with LCDs except maybe those LCDs with bright backlighting. Who was mandating "no micros?" Not me. The scheme to use an internal counting register as an initial accumulator is fairly recent (about within the last 6 years). "Discrete" logic (very discrete, including two- transistor flip-flops) counters go back to before 1960. Frequency counters used to cost thousands of dollars. My 6-digit RTL counter, using all-new parts off-the-shelf, cost less than $300 in 1967. Included many extra parts, some still in the workshop parts collection, unused. Had oven-controlled 10 MHz timebase crystal. Today my timebase standard is a TCXO which will become a TCVXO when the 60 KHz phase-locker receiver-controller is completed. The display is LED only because that is _easy_ to implement, a no-strain thing and it is bright. Yes, brightness takes current but this is a lab instrument and not battery powered. The total parts cost is less than $500 for both halves in 2003. Absolutely NO programming required. Yes, I do know the cost of manufactured instruments. Was calibrating HP 524 counters in 1960 (B model was all vacuum state, maximum count frequency of 10 MHz, neon "thermometer" numeric display, weight excellent for body building). Today they are orders of magnitude cheaper because they are orders of magnitude simpler. And they are orders of magnitude simpler because virtually all the circuitry is in the micro. I just took a quick look at my counter - under 20 parts. Go to LEDs and you probably triple that. But take out the micro and you are talking about hundreds of parts. A 16F84 or 16F71 as a frequency counter needs only a Schmitt trigger input to shape up the arbitrary waveform, maybe a "discrete" comparator IC if one is fussy, to count directly to 30 MHz. Going higher in frequency needs an extra "discrete" IC, a prescaler. That and an LCD assembly, one of many kinds available. The stuff NOT in "discrete hardware" is the PROGRAM. Do that one right and it is a fine little instrument. Do it wrong and there is a struggle to right it that may take hours and days, including bench measurement. Using others' source code is fine, much much easier. Provided the LCD assembly is the same as the authors', but if you have an LCD with a different sequence of data, of format, then it is back to the development program again. Perhaps I am downplaying the difficulty in learning how to apply micros, but you are certainly downplaying the difficulty of not applying them in this context. I thought I gave a reasonable reply the first time. Looked at several options. Were you gathering sticks for an Internet burning at the stake? :-) When giving suggestions it is better to cover the wide range of possibilities first rather than second-guess another's depth of knowledge, experience, or desire. It sounds like maybe you had some sort of anlog frequency display in mind, which I don't quite picture. Might be a cool thing, though. I've been using displays of many kinds in a long time, starting with gas numerics (Amperex Bi-Quinary tubes, like a Burroughs Nixie but 2 x 5, not 1 x 10)...and going through all the others except plasma dot matrix panels. If it's an LCD and there's a circuit driver IC for it, I will use those first. The weird waveforms have already been worked out and the ICs packaged. No driver IC and I start looking at other ways to display information. I don't know everything but I've been around a while and had hands-on in many things. When you say "discrete" active devices, try to put that in context of individual transistors. Or tubes. I've done both. Never again, I hope. You ought to call TTL and functional-equivalent CMOS logic as either SSI, MSI, or LSI (which they are) not "discrete." Done those in more than counter circuitry. Microprocessors and microcontrollers fall under the VLSI category. Microcontrollers are wonderful devices for making certain things with very low hardware count and near-minimal power demand. But, their application in special things requires PROGRAMMING. That isn't in the hardware. Such MUST be there. It CAN be learned. Some, like me, find programming fun. Others do not. I do not find having to learn new instruction sets for other micro families to be fun. Nuisance. Was there anything else? :-) Len Anderson retired (from regular hours) electronic engineer person |
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