The above is only mildly informative, and partly misleading. You can't talk of those things like they were magic.
Power dissipation on modern CMOS logic scales methinks with cube of voltage (energy in a MOS gate cap ~ voltage^3). So lower voltage will actually lower energy dissipation at a given clock rate, but it decreases noise margins. So lower voltage will increase probability of errors.
Low voltage is "hard" only on some motors. Specifically, it's not hard on typical motors in a PC. All motors in a PC -- that includes fans, floppy drive spindle & head, HD spindle, etc. -- are brushless DC motors. In a brushless motor, torque is proportional to current, and maximum speed is proportional to voltage on the DC bus feeding the speed regulator. Some fans are speed regulated, some aren't, but everything else IS.
If the voltage is high enough, speed will be in regulation. If the voltage is too low, they drop out of regulation. There isn't much that happens to a brushess DC motor if you run it on a voltage high enough for speed to stay in regulation. The winding isolation will fail if the voltage is too high, but otherwise it genuinely doesn't care. If anything, lower voltage is easier on the PWM switches that commutate the motor's windings.
As for optical drive failures: I think, everything else being the same, those fail solely due to contamination, and that would be proportional to some power of air flow (eddies have a great way of depositiong dust -- just ask mr. Dyson). Methinks namebrand systems may have higher air flow through the optical drive bay. This should be easy to measure.
As for marginal power supplies and whatnot: if anything, a failing power supply may have very poor transient response and will overvolt the logic on transients. CMOS logic doesn't get destroyed by low voltage, it gets destroyed by heat and/or high voltage. PCs place rather heavy transients on power supplies. The active regulation in the power supply has only some capacity to respond to transients, most of transient suppression is provided by capacitors.
Wet electrolytic capacitors lose their capacity quite quickly if they are operated at elevated temperatures. A typical "good" electrolytic capacitor may have useful life (20% drop in capacity) of 5000 hours at 105 degrees C, or somesuch. Some caps are only rated for 1000 hours, and/or for 80 C -- they are obviously cheaper. If you run those cheap capacitors HOT, they simply lose capacitance and eventually make the transient response of the power supply POOR. That's enough to produce spikes that have too high voltage, and they slowly degrade the logic circuitry on the motherboard, until something fails.
I'd say that since ATX power supplies only provide 3.3V, anything that fails on the motherboard will be run from 3.3V. That means that the CPU and memory will likely be intact, but southbridge would be suspect, as may be anything that plugs into PCI slots.
Timecube.com does not offer anything that can be proven/disproven. There's just a lot of words, but nothing of any use. We're not talking about that level of kookery here.
I think the really time-consuming kookery is one that looks, on the surface, genuine. Something like the Bogdanov Affair, where you have to wade through some deep maths in order to figure things out.
23% sales tax is enough to kill pretty much any economic activity.
You come from a different planet, then.
In Europe, typical VAT hovers around 20% methinks. In Germany, VAT is 19% for most non-food, non-agricultural products and services, and somehow they seem to be economically better off than the U.S.
People are emotionally attached to many things. That's what makes us human. Some of those things happen to be devices we use every day. I am emotionally attached to my Tektronix 7934 storage mainframe, thank you very much.
As for iPhones being overrated and made by a "terrible" company: everything can be thought of as overrated, when viewed from just the right angle. I'm a non-phone Apple user, but that was simply due to outgrowing the Linux desktop. I have used Linux on the desktop for almost 10 years, and I simply grew tired of things changing and breaking too often. I wanted to use it, not to tweak it -- thus OS X seemed like a good compromise. So far it has held up the promise, and recently VMware Fusion has really come through with graphics performance -- it is better than when running directly on my old Presario laptop.
Personally, I don't care much for iPhone since I use the cellphone rather sparsely -- 2-3 calls per week, tops. Thus I have no need for anything fancy. My phone is a $10 Nokia 1100 Tracfone, perhaps one of the best designed cellular telephones out there. Mind you it's supposed to be a telephone, not a kitchen sink, and it excels at the former while not being the latter. The battery lasts ~2 weeks.
You're part of the problem -- you're no better than Dell. Had you had any integrity left, you'd advise the customer that for ~$50 you can refurbish their motherboard and power supply with new capacitors...
I'd think that while there may not have been a golden age like that universally, there used to be exceptional corporations with pretty much impeccable image. Think Tektronix up to the end of 70s. Real innovators on the frontline of technology, with a corporate culture of excellence.
What "died" on them? If it was the capacitors, it's an easy and cheap fix. Saying that a computer "died" is like saying a car "died". WTF had really died? Did the wheels come off? Is the battery flat? Out of gas? WHAT????
Just replace the frakking capacitors already; if they are indeed the problem. It will cost you less than filing any sort of a lawsuit. Hire a decent electronics technician to do the rework. Why do people insist on using lawyers where the fix to the problem is maybe $35 per machine in parts an labor?!
A properly designed power supply is supposed to run indefinitely at rated load, in environmental conditions it was designed for. Everything should have been derated at the design stage to maintain proper performance at rated load. You should not have to add any extra safety factors as long as you can guarantee that the power consumption will stay where it's supposed to.
Shuttle's problem was that they were so cheap, they didn't buy power supplies that were properly designed and tested. Getting a 150W power supply from same el-cheapo vendor would have cost same as getting a 100W supply from a better vendor. You can't eat your cake and have it, too...
There are pretty much two ways those faulty capacitors could damage other components:
1. Damage from leaking electrolyte.
2. Damage from supply voltage transients.
#1 is the worst, since unless you properly wash the boards, the chemicals will slowly damage the traces and things will fail. Go to pretty much any test equipment related mailing list, where people routinely deal with Nichicon aftermatch.
#2 can cause degradation of semiconductor junctions and interconnects, so it could potentially lead to problems, but usually it's an on-off thing. Either the transients kill something, or they don't. As Jim Williams said at the end of one application note describing effects of transients on low voltage switching regulators: "Now I am become Death, the destroyer of worlds." -- Vishnu, to the Prince. [in] Bhagavad Gita
As for "marginal voltage" -- that's a meaningless expression. Marginal how? Too much ripple? Too low/too high average value? Poor transient response of the power supply? All of those things are relatively easy to measure if you have a modicum of electronics experience and some rudimentary tools.
IOW: I smell some cargo cultism. Computers are electronic devices, not magic.
I don't want to excuse what Dell did, but those capacitor issues were easy fixes. All you needed was a soldering iron and maybe $30 in parts per motherboard. Way quicker turnaround too -- shouldn't take more than an hour per machine. If you had many machines, it'd be obvious after a while that it'll be all or nothing, and then your part cost drop dramatically. If you bought replacement capacitors in qty. 1000, you'd be looking at half the price. I have fixed plenty of those boards myself, not only in PCs, also in quite a bit of test equipment (oscilloscopes, etc).
Back in elementary school in eastern Europe (before fall of the Wall), I used a re-purposed inverter from a hiking fluorescent light. We'd hook it up to door handles and get people zapped. Hothing harmful, just unpleasant. Then in high school we had lots of fun with portable lasers -- I had a tiny He-Ne laser pointer that'd eat up 9V batteries like crazy, and a laser pointer or two. Some girls got really scared upon seeing a bright red dot on their shoulder;) We were pretty careful not to shine into anyone's eye, mindful of reflective things, etc.
No one ever got into any trouble for that, but even had we got in trouble it would be maybe a note sent to parents. Getting kicked out from school for a year for a kid's prank -- WTF? And your parents' taxes paid for that? I feel sorry, all I can say.
As for sampling front ends: they don't really cut it due to parasitics -- they can be fast, but they aren't really accurate -- 12 bits of performance would be pushing it I think. Surely if you would be very clever and do, say, FEM of an integrated sampling bridge, and would characterize well all the parasitics and how they can be balanced out, it could probably be done. But using off-the-shelf parts with nothing exotic: I will believe it when I see it done.
The only practical way I know of is with a fast variable gain amp to blank overdrive -- this can readily be done, and this way you can test settling of 18 bit DAC's, and it's really no big deal once you try it and get it working. It doesn't cost much, either.
I'm playing with a blanking front-end that uses JW's variable transconductance amp approach, gated with fast comparators, and so far I've got it to recover within 100ns to 12 bits -- that's on the first try, on a real crappy breadboard. It's still far away from 10ns one expects the recovery to be in a 100MHz scope, but I should be able to cut it down to 25ns or so without doing anything extraordinary. And I don't really have all that much analog tinkering experience. Surely someone who knows what they are doing could get it to work way better and cheaper.
For an oscilloscope to be a truely universal instrument, it should have a minimum number of caveats. Poor signal fidelity (measured in single % - gimme a break), poor overload recovery, no antialiasing protection on many DSOs, ridiculous trigger holdoff times (orders of magnitude worse than on a $100 tek 7K mainframe from the 70s) -- those are the gripes I have with current technology.
Luckily the stuff that used to be out of reach financially is now either affordable or free: you can easily get a dev board with fast FPGA with multipliers on it, 64MB of DDR2 and a USB 2.0 connection for $200 IIRC. The software to do logic design for said FPGA is a free as in beer. You can have a 500MSPS 12 bit ADC for $200, and pretty much a transparent driver for it for 10% more. Fun times, I admit.
How could this be news? Everyone who bought those faulty capacitors from IIRC Nichicon faced same problems. Pretty much every single motherboard made back then had or has this problem. Neither is a long string of denials by a major corporation something new. Share value is sharply affected by such bad news, so noone who has trading stock will admit to anything, for as long as possible.
There are two sides to this: 1. Corporate greed. 2. Investor greed.
#1 is clearly understood. #2 means that share values are not influenced much by the financials of the underlying corporation. So tens of thousands, no, hundreds of thousands of investors, and automated trading systems, track such news and immediately sell upon hearing "bad news". Now the problem is that there is no way to actually see how such news will affect the financials of the company -- at least not immediately. Yet the markets *do* react immediately, in the most irrational manner, to all sorts of bad news.
I thought that we pretty much filed the Nichicon industrial espionage fiasco into relevant "history to be learned from" folders.
There are no decent 100MHz scopes in production. Unfortunately, there are no decent scopes in production, period.
By decent I mean something where the analog front end is actually worth anything. You'd think that in 2010 they could design something where the overdrive recovery matches the bandwidth, where you can meaningfully limit bandwidth (say in decade steps) to prevent aliasing of the sampled signal, where you can have better sensitivity than 1mV/div, and where you would have 10 or even 12 bit accuracy of the front-end so that you could actually measure something. Never mind doing mind boggling feats such as, maybe, digitally correcting the response of the probe+front-end so that you won't have to tweak the darn compensation pot, and that the aberrations will be down to 1 in 4096... Such "features" are not to be seen on anything affordable sporting 100MHz bandwidth, and there's no scope currently in production that would have all of those features:(
Alas, I'm not saying it's easy, but you'd hope to expect more from professionals in the field. I've done some prototypes using 16 bit ADCs, and due to issues of cost, manufacturability and patents for response calibration techniques, I've trimmed my expectations to a 14 bit ADC and a front end to give 12 bits of resolution with corrected aberrations at same level (4 LSBs at the ADC). Definitely doable, but boy I've got in over my head;)
Death to the ground clips -- seriously. They lost relevance as scopes crept past 30MHz or so. Yet every day you see students looking at signals coming out of modern gates with risetimes measured in single nanoseconds, with probes that use an alligator ground clip for reference. Facepalm.
This is like big boy electronics rookie mistake 101. Definitely not college electronics 101, as the latter is a rather useless exposition of the former. Read up on some Jim Williams's application notes from Linear Technology -- it's all there. That's how you do experiments in electronics. Pretty darn carefully, checking yourself at every step. JW's app notes in their entirety a required reading for anyone striving to be good at electronics.
LOL. That's *nothing* as far as "scale" goes -- what's 300,000 records these days... They managed to bungle things so bad that they would spend less money and be more efficient had they used something like MySql or Postgresql, and taught everyone involved how to type SQL queries by hand.
GPRS would be a logical choice for data transmission on a barebones GSM network. Assuming that those "rural" providers absolutely don't offer affordable GPRS, you can use circuit-switched connections and just send our own data instead of GSM-compressed voice. IIRC, most random bit patterns are valid GSM packets (in all variants of compression), so that shouldn't be a problem. I presume one could even encode the data such that it could survive decoding, as long as you have a digital channel (say mobile to ISDN or mobile to T1 connections).
Of course probably you can't easily do it from a Blackberry. But if you're a telecommunications researcher worth your salt, you can easily get access to a software GSM stack, and inject arbitrary data into voice circuits, instead of GSM-compressed packets. This lets you have 6.5kbit/s or 13kbit/s depending on base station's utilization.
Those are, of course, raw numbers. With protocol overheads, this should be something like 5/10kbit/s, one would hope. Presumably to utilize the link in a best way, the TCP/IP connections would be re-terminated at both ends, and data re-packed in some custom protocol.
So using SMS for all this? It's the approach of least resistance, something you could do on a weekend as a proof of concept for your inquisitive kid maybe, but nothing more. BOO to the "reasearcher".
They have done some cool things to achieve the effect. Key problems to overcome were:
1. The mirror isn't. A regular rotating mirror would allow viewing from a narrow range of heights. The mirror they use is diffuse in the vertical direction, while acting like a regular mirror in horizontal direction.
2. How to get a fscking fast projector: they use a regular DVI stream, but encode multiple one-bit images into the components. That way a 16-bit-per-pixel stream gets you 16 binary frames per each DVI frame. With 200Hz refresh rate, that is 3200 monochrome frames per second. To decode the stream, they use a custom FPGA-based decoder between the DVI input and the DLP chip.
3. How to render the source material so that it looks good -- and do it in real time, too. They overcome various sources of distortion,
All in all, methinks this is worthy of re-publishing, even if it's stale. Very cool technology.
The dyes I haven't thought about, admittedly. I've never had what looked to be the effects of low SNR due to a fading dye. It was always flaking of the data layer...
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The above is only mildly informative, and partly misleading. You can't talk of those things like they were magic.
Power dissipation on modern CMOS logic scales methinks with cube of voltage (energy in a MOS gate cap ~ voltage^3). So lower voltage will actually lower energy dissipation at a given clock rate, but it decreases noise margins. So lower voltage will increase probability of errors.
Low voltage is "hard" only on some motors. Specifically, it's not hard on typical motors in a PC. All motors in a PC -- that includes fans, floppy drive spindle & head, HD spindle, etc. -- are brushless DC motors. In a brushless motor, torque is proportional to current, and maximum speed is proportional to voltage on the DC bus feeding the speed regulator. Some fans are speed regulated, some aren't, but everything else IS.
If the voltage is high enough, speed will be in regulation. If the voltage is too low, they drop out of regulation. There isn't much that happens to a brushess DC motor if you run it on a voltage high enough for speed to stay in regulation. The winding isolation will fail if the voltage is too high, but otherwise it genuinely doesn't care. If anything, lower voltage is easier on the PWM switches that commutate the motor's windings.
As for optical drive failures: I think, everything else being the same, those fail solely due to contamination, and that would be proportional to some power of air flow (eddies have a great way of depositiong dust -- just ask mr. Dyson). Methinks namebrand systems may have higher air flow through the optical drive bay. This should be easy to measure.
As for marginal power supplies and whatnot: if anything, a failing power supply may have very poor transient response and will overvolt the logic on transients. CMOS logic doesn't get destroyed by low voltage, it gets destroyed by heat and/or high voltage. PCs place rather heavy transients on power supplies. The active regulation in the power supply has only some capacity to respond to transients, most of transient suppression is provided by capacitors.
Wet electrolytic capacitors lose their capacity quite quickly if they are operated at elevated temperatures. A typical "good" electrolytic capacitor may have useful life (20% drop in capacity) of 5000 hours at 105 degrees C, or somesuch. Some caps are only rated for 1000 hours, and/or for 80 C -- they are obviously cheaper. If you run those cheap capacitors HOT, they simply lose capacitance and eventually make the transient response of the power supply POOR. That's enough to produce spikes that have too high voltage, and they slowly degrade the logic circuitry on the motherboard, until something fails.
I'd say that since ATX power supplies only provide 3.3V, anything that fails on the motherboard will be run from 3.3V. That means that the CPU and memory will likely be intact, but southbridge would be suspect, as may be anything that plugs into PCI slots.
Timecube.com does not offer anything that can be proven/disproven. There's just a lot of words, but nothing of any use. We're not talking about that level of kookery here.
I think the really time-consuming kookery is one that looks, on the surface, genuine. Something like the Bogdanov Affair, where you have to wade through some deep maths in order to figure things out.
23% sales tax is enough to kill pretty much any economic activity.
You come from a different planet, then.
In Europe, typical VAT hovers around 20% methinks. In Germany, VAT is 19% for most non-food, non-agricultural products and services, and somehow they seem to be economically better off than the U.S.
People are emotionally attached to many things. That's what makes us human. Some of those things happen to be devices we use every day. I am emotionally attached to my Tektronix 7934 storage mainframe, thank you very much.
As for iPhones being overrated and made by a "terrible" company: everything can be thought of as overrated, when viewed from just the right angle. I'm a non-phone Apple user, but that was simply due to outgrowing the Linux desktop. I have used Linux on the desktop for almost 10 years, and I simply grew tired of things changing and breaking too often. I wanted to use it, not to tweak it -- thus OS X seemed like a good compromise. So far it has held up the promise, and recently VMware Fusion has really come through with graphics performance -- it is better than when running directly on my old Presario laptop.
Personally, I don't care much for iPhone since I use the cellphone rather sparsely -- 2-3 calls per week, tops. Thus I have no need for anything fancy. My phone is a $10 Nokia 1100 Tracfone, perhaps one of the best designed cellular telephones out there. Mind you it's supposed to be a telephone, not a kitchen sink, and it excels at the former while not being the latter. The battery lasts ~2 weeks.
You're part of the problem -- you're no better than Dell. Had you had any integrity left, you'd advise the customer that for ~$50 you can refurbish their motherboard and power supply with new capacitors...
I'd think that while there may not have been a golden age like that universally, there used to be exceptional corporations with pretty much impeccable image. Think Tektronix up to the end of 70s. Real innovators on the frontline of technology, with a corporate culture of excellence.
What "died" on them? If it was the capacitors, it's an easy and cheap fix. Saying that a computer "died" is like saying a car "died". WTF had really died? Did the wheels come off? Is the battery flat? Out of gas? WHAT????
Just replace the frakking capacitors already; if they are indeed the problem. It will cost you less than filing any sort of a lawsuit. Hire a decent electronics technician to do the rework. Why do people insist on using lawyers where the fix to the problem is maybe $35 per machine in parts an labor?!
A properly designed power supply is supposed to run indefinitely at rated load, in environmental conditions it was designed for. Everything should have been derated at the design stage to maintain proper performance at rated load. You should not have to add any extra safety factors as long as you can guarantee that the power consumption will stay where it's supposed to.
Shuttle's problem was that they were so cheap, they didn't buy power supplies that were properly designed and tested. Getting a 150W power supply from same el-cheapo vendor would have cost same as getting a 100W supply from a better vendor. You can't eat your cake and have it, too...
There are pretty much two ways those faulty capacitors could damage other components:
1. Damage from leaking electrolyte.
2. Damage from supply voltage transients.
#1 is the worst, since unless you properly wash the boards, the chemicals will slowly damage the traces and things will fail. Go to pretty much any test equipment related mailing list, where people routinely deal with Nichicon aftermatch.
#2 can cause degradation of semiconductor junctions and interconnects, so it could potentially lead to problems, but usually it's an on-off thing. Either the transients kill something, or they don't. As Jim Williams said at the end of one application note describing effects of transients on low voltage switching regulators: "Now I am become Death, the destroyer of worlds." -- Vishnu, to the Prince. [in] Bhagavad Gita
As for "marginal voltage" -- that's a meaningless expression. Marginal how? Too much ripple? Too low/too high average value? Poor transient response of the power supply? All of those things are relatively easy to measure if you have a modicum of electronics experience and some rudimentary tools.
IOW: I smell some cargo cultism. Computers are electronic devices, not magic.
Marketing people don't understand that sometimes too much of a good thing is a bad thing: too much choice is bad, too.
I don't want to excuse what Dell did, but those capacitor issues were easy fixes. All you needed was a soldering iron and maybe $30 in parts per motherboard. Way quicker turnaround too -- shouldn't take more than an hour per machine. If you had many machines, it'd be obvious after a while that it'll be all or nothing, and then your part cost drop dramatically. If you bought replacement capacitors in qty. 1000, you'd be looking at half the price. I have fixed plenty of those boards myself, not only in PCs, also in quite a bit of test equipment (oscilloscopes, etc).
It hopped away, darn :)
Back in elementary school in eastern Europe (before fall of the Wall), I used a re-purposed inverter from a hiking fluorescent light. We'd hook it up to door handles and get people zapped. Hothing harmful, just unpleasant. Then in high school we had lots of fun with portable lasers -- I had a tiny He-Ne laser pointer that'd eat up 9V batteries like crazy, and a laser pointer or two. Some girls got really scared upon seeing a bright red dot on their shoulder ;) We were pretty careful not to shine into anyone's eye, mindful of reflective things, etc.
No one ever got into any trouble for that, but even had we got in trouble it would be maybe a note sent to parents. Getting kicked out from school for a year for a kid's prank -- WTF? And your parents' taxes paid for that? I feel sorry, all I can say.
LOL. Worth modding up!
As for sampling front ends: they don't really cut it due to parasitics -- they can be fast, but they aren't really accurate -- 12 bits of performance would be pushing it I think. Surely if you would be very clever and do, say, FEM of an integrated sampling bridge, and would characterize well all the parasitics and how they can be balanced out, it could probably be done. But using off-the-shelf parts with nothing exotic: I will believe it when I see it done.
The only practical way I know of is with a fast variable gain amp to blank overdrive -- this can readily be done, and this way you can test settling of 18 bit DAC's, and it's really no big deal once you try it and get it working. It doesn't cost much, either.
I'm playing with a blanking front-end that uses JW's variable transconductance amp approach, gated with fast comparators, and so far I've got it to recover within 100ns to 12 bits -- that's on the first try, on a real crappy breadboard. It's still far away from 10ns one expects the recovery to be in a 100MHz scope, but I should be able to cut it down to 25ns or so without doing anything extraordinary. And I don't really have all that much analog tinkering experience. Surely someone who knows what they are doing could get it to work way better and cheaper.
For an oscilloscope to be a truely universal instrument, it should have a minimum number of caveats. Poor signal fidelity (measured in single % - gimme a break), poor overload recovery, no antialiasing protection on many DSOs, ridiculous trigger holdoff times (orders of magnitude worse than on a $100 tek 7K mainframe from the 70s) -- those are the gripes I have with current technology.
Luckily the stuff that used to be out of reach financially is now either affordable or free: you can easily get a dev board with fast FPGA with multipliers on it, 64MB of DDR2 and a USB 2.0 connection for $200 IIRC. The software to do logic design for said FPGA is a free as in beer. You can have a 500MSPS 12 bit ADC for $200, and pretty much a transparent driver for it for 10% more. Fun times, I admit.
How could this be news? Everyone who bought those faulty capacitors from IIRC Nichicon faced same problems. Pretty much every single motherboard made back then had or has this problem. Neither is a long string of denials by a major corporation something new. Share value is sharply affected by such bad news, so noone who has trading stock will admit to anything, for as long as possible.
There are two sides to this:
1. Corporate greed.
2. Investor greed.
#1 is clearly understood. #2 means that share values are not influenced much by the financials of the underlying corporation. So tens of thousands, no, hundreds of thousands of investors, and automated trading systems, track such news and immediately sell upon hearing "bad news". Now the problem is that there is no way to actually see how such news will affect the financials of the company -- at least not immediately. Yet the markets *do* react immediately, in the most irrational manner, to all sorts of bad news.
I thought that we pretty much filed the Nichicon industrial espionage fiasco into relevant "history to be learned from" folders.
Yes, it can.
There are no decent 100MHz scopes in production. Unfortunately, there are no decent scopes in production, period.
By decent I mean something where the analog front end is actually worth anything. You'd think that in 2010 they could design something where the overdrive recovery matches the bandwidth, where you can meaningfully limit bandwidth (say in decade steps) to prevent aliasing of the sampled signal, where you can have better sensitivity than 1mV/div, and where you would have 10 or even 12 bit accuracy of the front-end so that you could actually measure something. Never mind doing mind boggling feats such as, maybe, digitally correcting the response of the probe+front-end so that you won't have to tweak the darn compensation pot, and that the aberrations will be down to 1 in 4096... Such "features" are not to be seen on anything affordable sporting 100MHz bandwidth, and there's no scope currently in production that would have all of those features :(
Alas, I'm not saying it's easy, but you'd hope to expect more from professionals in the field. I've done some prototypes using 16 bit ADCs, and due to issues of cost, manufacturability and patents for response calibration techniques, I've trimmed my expectations to a 14 bit ADC and a front end to give 12 bits of resolution with corrected aberrations at same level (4 LSBs at the ADC). Definitely doable, but boy I've got in over my head ;)
Death to the ground clips -- seriously. They lost relevance as scopes crept past 30MHz or so. Yet every day you see students looking at signals coming out of modern gates with risetimes measured in single nanoseconds, with probes that use an alligator ground clip for reference. Facepalm.
This is like big boy electronics rookie mistake 101. Definitely not college electronics 101, as the latter is a rather useless exposition of the former. Read up on some Jim Williams's application notes from Linear Technology -- it's all there. That's how you do experiments in electronics. Pretty darn carefully, checking yourself at every step. JW's app notes in their entirety a required reading for anyone striving to be good at electronics.
LOL. That's *nothing* as far as "scale" goes -- what's 300,000 records these days... They managed to bungle things so bad that they would spend less money and be more efficient had they used something like MySql or Postgresql, and taught everyone involved how to type SQL queries by hand.
OK, I just don't get something.
GPRS would be a logical choice for data transmission on a barebones GSM network. Assuming that those "rural" providers absolutely don't offer affordable GPRS, you can use circuit-switched connections and just send our own data instead of GSM-compressed voice. IIRC, most random bit patterns are valid GSM packets (in all variants of compression), so that shouldn't be a problem. I presume one could even encode the data such that it could survive decoding, as long as you have a digital channel (say mobile to ISDN or mobile to T1 connections).
Of course probably you can't easily do it from a Blackberry. But if you're a telecommunications researcher worth your salt, you can easily get access to a software GSM stack, and inject arbitrary data into voice circuits, instead of GSM-compressed packets. This lets you have 6.5kbit/s or 13kbit/s depending on base station's utilization.
Those are, of course, raw numbers. With protocol overheads, this should be something like 5/10kbit/s, one would hope. Presumably to utilize the link in a best way, the TCP/IP connections would be re-terminated at both ends, and data re-packed in some custom protocol.
So using SMS for all this? It's the approach of least resistance, something you could do on a weekend as a proof of concept for your inquisitive kid maybe, but nothing more. BOO to the "reasearcher".
They have done some cool things to achieve the effect. Key problems to overcome were:
1. The mirror isn't. A regular rotating mirror would allow viewing from a narrow range of heights. The mirror they use is diffuse in the vertical direction, while acting like a regular mirror in horizontal direction.
2. How to get a fscking fast projector: they use a regular DVI stream, but encode multiple one-bit images into the components. That way a 16-bit-per-pixel stream gets you 16 binary frames per each DVI frame. With 200Hz refresh rate, that is 3200 monochrome frames per second. To decode the stream, they use a custom FPGA-based decoder between the DVI input and the DLP chip.
3. How to render the source material so that it looks good -- and do it in real time, too. They overcome various sources of distortion,
All in all, methinks this is worthy of re-publishing, even if it's stale. Very cool technology.
The dyes I haven't thought about, admittedly. I've never had what looked to be the effects of low SNR due to a fading dye. It was always flaking of the data layer...