If you are in any type of relatively high power RF environment, you need to go balanced- it should actually be cheaper than coax for audio, though the transformers will increase the total cost. I've worked at a couple radio stations- all professional (studio) equipment I've seen is balanced, usually 600 ohms. In a nasty EMI environment, balanced is the only way to go. Unless you are trying to make a studio with incredible S/N, you don't need to be super careful about wiring- you can get great sounding audio through punch-blocks. You do have to be careful about phase though- make sure you used polarized wire for your interconnects.
Most important: Label extensively, and take careful notes.
Using that extra pair can cause a serious drop in the performance of your Ethernet- the twisted pair/differential driver set up is pretty good at eliminating noise induced by outside sources, but only if the source of the noise is at a distance >> the spacing of the pairs. Since all 4 pairs are in the same shield, running intercom on the unused 2 pairs can interfere with the data (and vice versa). Also- you have to watch out since most Ethernet cards terminate the unused pairs into a direct short or into a 75 ohm resistor. Depending on how often you use it, it may still be acceptable, but you need to be aware that it can affect things.
Also, using the extra pairs will prevent you from running copper-gigabit ethernet, which uses all 4 pairs.
Well, really, I did try and simplify the solution, since, as posed, the solution would be underdetermined. I need more data to determine the optimal solution: the cost of the system, with a depreciation schedule, the specific MTTF and MTBF of the system, backlight replacement costs, and time, with projections into the future, including contingency plans if any of the constituent parts reaches end-of-life in the service interval. Also, I think you would have to factor in the cost of the downtime of the system with a respect to lost productivity. You could recoup some of the cost by dedicating the laptop with a dead backlight to a home server, or possibly as a tax deduction, but that is a question better posed to your accountant.
I think that this quickly changes from a failure analysis problem to an accounting problem, which takes it far out of my range of experience, which is primarily engineering.
With one or two of the lifetime lengthening measures, and without expending the effort on the PDE solution to the problem, you can probably easily extend the lifetime way past the expected lifetime of the laptop, or at least past the "crap, I spilled Coke all over my keyboard" event.
You have another concern, as detailed in this PDF. Backlight lifetime is going to go down as you increase the brightness. From a brief google search, backlight lifetimes run from 20,000 to 50,000 hours, with intensity decreasing with time, and end-of-life determined as 50% brightness of new. You may declare it too dim far before that time, but even then 20,000 hours is 2500 8 hour days, or almost seven years at 8 hours a day.
That gives you some options:
1. Don't run the backlight at 100% intensity- try to reduce the lighting in the areas where you are using the laptop. This saves batteries too.
2. Turn off the backlight after something like.5 to 1 hour of non-use of the system.
3. If you must leave the monitor on to be able to check things at a glance, reduce the intensity as much as possible.
Also, just for the general lifetime of your laptop, use the power-down/suspend power saving features- laptops are dense little packages of electronics- which generate a lot of heat, but don't dissipate it well. Heat kills electronics and batteries, try to keep the heat down, and you will greatly improve the lifetime of the whole laptop, not just the screen. If you're not using it, and the laptop is warm, you're wasting power and laptop lifetime.
I was able to get a (photocopy of a) manual for one of my old (dead) scopes- an old Dumont 1100P- I believe they have been out of business for over 30 years. I got mine from W7FG Looking through his catalog (of photocopies), I don't see your RCA in his list, but there are a number of people like this guy who sell old manuals. Check some amateur radio sites- they're going to be the guys that have them if they are available. I don't know how they deal with the whole copyright issue...
Right out of school, a job in the government is actually pretty good. For most people, after graduating, you have a lot of theoretical knowledge, but little practical, real world knowledge, and this leads to having misconceptions about what the you really want to do with the knowledge you gained in school.
A strange thing about the government is that while they are limited in legislation as to what they can pay their employees, the same legislation gives them budgets that they must spend or get that much less for next year. In my experience, this leads to getting top of the line hardware, stuff that the private sector is drooling over, but is not willing to pay for. You can learn now on what will be the hot technology in the private sector in a few years.
Since the government pays less than the private sector, there is much more internal opportunity since they are chronically understaffed. If you want to work on a wide variety of things, the opportunity is there. My experience with the private sector, especially in big companies, is that once you have shown proficiency in a particular area, such as franistat widgets, you're more likely to be spending the rest of your career in making franistat widgets. Likely you will be very, very good at making the franistat widgets, but you may be left out in the cold once franistats are replaced by harbintrons, where you never had the opportunity to learn them.
Also, I have found that many of the people that are working for the government, especially in research, are very, very, very good at what they do, particularly those that have been at it for 20 or 30 years, and they can be a very good resource for you to learn from. Yes, there are idiots working for the government, because it is hard to fire them. In my experience, those people are easy to spot and to avoid. The people that you want to learn from are there, too. They are the people consumed in/by the technology and not jaded by the pursuit of money, status, or power. In private industry, I've found the latter much harder to find.
On the down side, the pay sucks, and promotion potential is poor. I spent 7 years working for the Federal government, 1 for the state (at a public university), and the last year in private industry. I have gotten to work on a lot of cool things, and I have a wide variety of experience. I can't say I'm completely satisfied, I do believe that I am more satisfied that I would have been if I went into private industry directly after graduation.
Bluetooth has been, and is right now, largely vaporware, though it is slowly gaining ground. The first big hurdle has been cheap, integrated chipsets, and we should have good, mass produced silicon very soon, if it isn't here already (if they are here, they've come in the past 6 months). Once the installed base is here, we'll need the infrastructure to support it, unfortunately, no-one will build the infrastructure, until there is a large installed base. When the larger infrastructure is in place, the demand will rise. Right now, we have no infrastructure, and therefore no demand. This is why the Bluetooth silicon makers have pretty much only talked to the big players in the electronics industry, like Nokia, and the big computer manufacturers. I used to work for a smaller manufacturer of devices, and the Bluetooth silicon vendors didn't want to talk to us when we were talking about paltry volumes of 10-50K units/year.
This is much like what happened with cellular phones- at first a neat gadget, but not very useful due to the lack of coverage, then better coverage, but awfully expensive, and now we are at the point where the coverage is pretty extensive and the costs can rival a landline. The demand for ubiquitous networking is growing- something will fill the gap.
At a place I used to work, used a system developed by MacLeod Technologies, the CONAC System. They used to have a web page, but I can't find it. Very small company, snd I don't know if they are in buisness anymore. Here's a PDF that has a bit of a description. A google search on CONAC gets a few more hits. It is very accurate over a limited area like a yard- it works like this: Spin a laser that has a somewhat fan shaped beam, with the axis of the fan vertical, and sweeping 360 degrees of azimuth. Place (laser) recievers at known, fixed locations around the perimeter of the area. When the laser sweeps over a beacon, record the time. The time betwwen each reciever responding will give you azimuth to each reciver. If you have a reciever on the robot itself, you know which direction your robot is pointing, in relation to the array of recievers. With all this information, you can derive position and azimuth of your robot.
Make sure you have >> 3 recievers so you can have an overdetermined solution, so that if one reciever is blocked by a person, tree, or errant butterfly, you can still determine the position.
This *does* work, as long as you don't get too far from the sensors. The farther the sensor is away, the less accurate the position solution. You might want to implement multiple sorts of sensors, including compass and whatever else you can, and feed them all as inputs to a Kalman filter, which should give you a more robust solution.
If you'd like to talk about this, de-obfuscate, and drop me an email. I'd love to have a system like this for my *own* lawn.
Assembly is very much alive and well with microcontrollers, especially the 8 bit micros (PIC, AVR, Scenix/Ubicomm, etc.). C is making inroads, but for any sort of optimization, you still need to be able to look at the code the compiler generates and understand what it is doing. This is very important when you are trying to deal with low latency interrupts, tight timing loops, and small memory sizes.
For the most part, developing in a higher level language is faster, more robust, and a heck of a lot easier. Knowing assembly greatly enhances the understanding of what the computer is actually doing, and how the computer is doing it. If speed and size are important, do assembly. The speed on many applications is strongly limited by I/O- it doesn't make as much sense to use the considerable strength and difficulty for those type of applications, but if you're trying to do real time DSP, the speed of assembly, especially when dealing directly with fast I/O, is very valuable.
It really is a matter of using the most appropriate tool for the job. High level languages do a lot of things very well. Assembly also does many things very well. C can map very closely to assembly in some circumstances. Any sort of programming language is just a layer between your ideas and the op-codes that the computer executes. Assembly is just a bit more precise, like a surgeons scalpel, compared to the dull broadsword that is Visual Basic. Insert your own cutting implement metaphor for your favorite language.
From your comments above, I think you realize that from a purely economic basis, solar, in particular photovoltaics, don't usually make sense. On the other hand if you want to do this project just cuz you want to, have fun, and here's some thoughts.
Efficiency: PV's output DC. Virtually every appliance you have uses AC, but that doesn't mean that they won't necessarily run on DC. Incandescent light bulbs will work on DC just fine- though they are very inefficient. Pumping the output of your PV array into an inverter to generate AC is a guaranteed source of inefficieny. Try to get as much as you can running off of DC- switch to a laptop that you can charge with the PVs, rig up some lighting with efficient bright white LEDs. You'll have to give up anything that uses a transformer- since by definition, they don't work at DC, but with some creativity, you should be able to bypass wall warts and the like with a custom power supply.
DC has some other things to watch out for, especially at higher voltages- it can be more dangerous than AC- an arc has less chance to extinguish itself, so if you are switching high voltage, high current DC, you need special switches that will break an arc that is started on contact opening. Also, DC will cause your plugs and such to corrode faster, which can make high resistance connections, and possibly a fire hazard.
I myself have considered a DC system in my home for reliability reasons- I get lots of short term outages, with the occasional long term outage. With a 12V system that powers my computers, I could battery back it up, and then use a simple generator set-up to take care of the longer outages, using a lawnmower engine and a car alternator. You could use a similar system, using PV's to charge up your batteries, with an AC system to take over charging when there is not enough sunlight to do the job.
I'm an EE, I got my BSEE in '91, and my MSEE in '97 (while I was working full time). When I graduated in '91, the economy was in a downturn that really affected my chances for a job- I had two separate interviews (on-site) that said, "we had jobs when we did the on campus interview, but since then, we don't." I was a good student, good GPA, but I was being picky. I decided to concentrate on doing the things that I enjoyed, those things that I wanted to spend the rest of my life doing. I took a job that was for less pay than many of my peers (at a government research lab), but I had the opportunity to learn much more than I would have if I had gone into private industry right away. Now, I'm in demand. I have a broad set of skills that companies like, and I get to do cool shit.
If you got into engineering for the money, I feel sorry for you, you'll never feel fufilled. I don't know of any engineers that are going hungry, and only anecdotal evidence of a few that drive Ferraris. You may not be able to pull down the big bucks now, but, in truth, straight out of school, most engineers don't know their ass from a hole in the ground, and they shouldn't be making the big bucks until they can prove their worth to their company. When you graduate, you've only completed the basics for an engineering job, it will take you years more effort to become a truly great engineer. Engineering is all about getting things done with the resources available. School gave you the tools to do the job, but only real life experience will give you the practice at using those tools. You will spend the rest of your engineering career honing your skills. Right now is the time to find an experienced engineer (and technician) to work with, so you can learn to use those tools with precision, style, and creativity. There are plenty of those types of jobs available now, though they may not be as glamorous. Don't be cocky, approach every opportunity with an open mind and a willingness to listen and to learn.
There are many, many students out there that have great things on their transcripts, but have no passion for engineering. Find stuff that makes you say "Wow." In that way you will excel. Interviewers notice that, many of them will be engineers that have been on the other side of the table.
As to stability, there is no guarantee of employment with any job. If you develop indespensable skills, you will be less likely to be fired, and better able to get a new position when you want it. Right now RF and analog positions are in demand because most schools are churning out engineers that are heavily digital-oriented, and ignoring the analog portion. ('Cept for DSP.) But speeds are getting so high that analog and digital are blurring into one. There are other examples out there. The best RF engineers I know are all nearing retirement age. When they are gone, so is their knowledge. You have the opportunity to mold yourself into what is in demand, not now, but 10 years from now.
Yeah, its gotta take a lot of effort on the part of the person that needs the help too. But nobody's going to get themselves out of poverty by just waiting around. If the computer can give them the idea that they can improve their lot in life, then it succeeded. A computer in my view is just a tool. Some people know how to use it, some don't, but very few of the people who don't know how to use it can't learn.
I'd rather see them spend that money giving out computers than teaching them how to chop down the rainforest for an unsustainable farm, or to raise more cattle for McD's.
I agree that the internet is no more the answer to poverty than a library card is the answer to illiteracy. But it can help, give incentive to work for the future, rather than perpetuate the status quo. The internet is only part of the answer. Education is another very important part. The internet can give us information, but most importantly it gives us communication. Communication is an empowering technology, it enables people to see beyond their locale.
If a farmer has information about the weather, he can better plan his planting and harvesting. A factory worker can search for a better job. A merchant can search for the best wholesaler for the wares he sells. A craftsman can find out how much the things he creates are actually worth, and price them accordingly, rather than trust the middleman who only has his own bottom line in mind.
If you're going to give the poverty stricken anything, give them opportunity. That's what this cheap internet terminal can give. Viewing a computer as a luxury relegates the computer to the level of television, a one way medium. But the real power of the internet is that even though the bandwidth is largely one way (to the user) there is still a channel out (to the world). You can just spectate, but you have the opportunity to participate, and it is up to the individual to choose.
I guess I can't fully convince you yet, but I do know one thing for sure, the capability to do this has to be built with hardware first, before the software would be able to use it. That hardware is available right now- since wake-on-lan is becoming popular. Manufacturers are building it into products right now. If there was not a demonstrated need, they wouldn't be. As to software that supports that... I dunno, I'm a hardware guy.
History has proven that software will be written that will fill the needs that present themselves. If it isn't available now, it will be.
Energy savings just for the sake of the environment don't take off quickly, but if there is money to be saved, stand back, it's gonna happen.
I guess the real question I've got is this: Why would you want your server to sleep?
Pretty simple, really- lets say you're using load balancing, and to handle your peak load, and you need 20 servers, but at off peak times, you only need 25% of the capacity, 5 servers. If you can shut down the other 15, you would have about a 75% power savings during off-peak times. This is especially the case if the market you are serving is reigonal.
Since we're talking about servers here, anyone who is running a bunch of servers without a KVM (keyboard, video, mouse) switch is pretty foolish. With a KVM you need only one monitor for a whole raft of servers. The technology is improving, there is at least one company that is sending all the KVM info from the servers to the switch via a single dedicated Cat5/RJ45 cable (per machine).
Hooking this up to a flat panel monitor would save power, of course.
The KVM is nice for when you need to have access to the console, but if you can handle a headless server, an xterm is even nicer (as long as you are running a Unix variant).
As to a flat panel being cheaper in the long run... my 21" monitor is rated at about 200W, if a comparable flat panel draws 30% of that, or 60W. I'll assume an (outrageous) rate of $0.50/kWh. It costs about $0.10/hr to run the CRT, and $0.03/hr to run the FPD, a savings of $0.07/hr. Pricewatch gives me about $500 for a cheap 21", and $1300 for a cheap 18" FPD, an $800 price difference. You would have to run your monitors for about 11,500 hours for the price of the FPD to beat the CRT. If you work 10hr/day, 5 days a week,(and turn the monitor off when you're not there) it would take almost 4.5 years for the FPD to pay for itself. I'm not exactly sure of the California electricity rates- I encourage someone who has better numbers to correct mine.
At a more typical rate of $0.10/kWh, it costs $0.02/hr for the CRT and $0.006/hr for the FPD, it would take 57,000 hours, or almost 22 years for the FPD to pay for itself.
Flat panels are nice, but, I think you're going to need another arguement to convince your boss.
As previously reported, what's going to happen to the broadband adapter now that they're clearing out inventory? Looking at the Sega store listing, it is classified as backordered. Will they be filling those orders? Will it be available somewhere else (other than ebay)?
Sadly but ture, the faster and faster processors that we get, the lazier and lazier the coders get
Absolutely. Those are the hacks of the programming world, but there will always be a small subset of people who will create tight efficient code. Many programmers opt to make sloppy, inefficient code because they can get it out quickly without a heck of a lot of theory. Those that do will continue to make mediocre code. But that will be for mundane tasks. There is plenty of mundane code that needs to be written. I, for one, would prefer to have the best of the best programmers working on the tough problems, not relegated to the run-of-the-mill problems because nobody else can produce something workable.
There are plenty of applications that require more computing power than we have commonly available now- like real time image recognition, real time speech (as spoken) recognition, photorealistic image rendering. This type of problem is where our best programmers should be working.
Heck, the advent of Linux showed us that we could still do great things with a 386 when the 486 was all the rage. As we get more computing power, the realm of the possible will continue to expand.
...the more we keep discussing this, the more we agree...
There is one point where we disagree-- What I would like to see, which would be a huge change in the way we think about our private data, is that, by default, all private information is private. If there is any personally identifiable information (name, address, SSN, etc.), it would automatically be deemed private. It could be collected without explicit permissions of the "owner" of the data, but it could not be distributed without the permission of the "owner." If you can't gain the permission of the owner? You can't distribute it.
I have some difficulty with the panhandler analogy: once I give money away, really, I have no say. I would like to know that my money is going to food and shelter rather than Maddog and Marlboros, but I have no say. Enough pennies will make a million dollars... This data can be aggregated to something much more valuable. It is about data security- when I used to work with classified data, we got annual briefings on OPSEC -Operational Security- which basically meant, keep everything to yourself, because you want to deny "the enemy" any sort of information advantage. Something you may think is trivial may be the key to tying together a whole raft of data. Enough generic demographic data can zoom right in on an individual. I want to be able to trust who I give my information to, and make sure they don't use it against my wishes. There does need to be some higher controlling authority- and in this case it is the government.
Can it happen? I don't know. Making and enforcing these provisions would be daunting, but I think it is the direction we ought to go towards, less will be equivalent to no privacy at all. Data storage and processing power keeps getting cheaper, without some restriction on the collection and sharing of personally identifiable information, there eventually will be no such thing as privacy.
(Whoowhee, I'm sounding like a real zealot. Guess I ought to go back to my cabin and finish my manifesto.)
My major peeve, as stated above, is that we're setting the fox to guard the henhouse. We should at least hobble the fox first.
Absolutely. As a citizen of a country, we have a right to at least try to affect the policies of the government. Unless you're a shareholder in a company, you don't have any grounds to ask a company to restrain itself. If you're not, you can ask, but they have every right to ignore you.
Or, consider this it boils down to who "owns" that information- My private information is mine- I should retain ownership, and from that, control. If I give it to you, you can use it, but you should have no right to distribute it further, unless I grant you that right.
But this makes me wonder, What are the negative results of restricting my private information? I might miss some direct mail, I might miss out on some unsolicited credit card offers. What else? Has this been touched on elsewhere in this article's discussion?
Note that the examples you've listed are all examples of governmental agencies selling your info.
True, but the companies to keep our eyes on are the private corporations buying that information and selling the data about us. They can aggregate it, correlate different information and come to their own conclusions. This aggregation is what "data mining" is all about. What if the database is screwed up? Will you be able to find out before it screws up your life? You miss out on a job? You miss out on a home loan? There are mechanisms to correct mistakes, but they are universally slow.
Once it leaves the government's hands, they have lost all control. All government agencies are accountable, for the most part, (ultimately) to the citizens of that country. (Yes, I know there are major exceptions.) If there is enough uproar (as there was a few years back about driver's license records, which enabled a stalker to find, and ultimately murder, a sit-com actress) the government will change its laws.
A company is only accountable to its shareholders. If the company runs afoul of the law, and is punished, ultimately the shareholders pay the cost. That company has no obligation to the public, other than to obey the law.
Right now, privacy is being treated as an opt-out process- I would prefer if it was, by default, opt-in. Since we don't necessarily know all the data that is collected about us, I want all information about me to be considered private, and let me decide what is to be made public.
If a private company wants to distribute it, they should have to tell me what information they are selling and to whom. I would prefer it if my state would not distribute this information, but ultimately, it will have to be a federal action that forces privacy. As it stands now, if it is not expressly prohibited, it is permitted.
(to be truthful, it appears that for the most part, we agree, unless, I'm being particularly dense and failing to catch on to your irony)
If you don't give your info out, people don't have it. If you don't specify that it be kept confidential, it won't be, nor should it be.
Much easier said than done. Some things can't be kept out of the public record- such as deed information- I've bought 2 houses, and I have no choice but to have that information available. I don't mind if the local public utility uses it to send me a letter informing me of something they have to do in the right-of-way. On the other hand, this same database is *SOLD* by the state (I'm in the USA) to direct mailers, Mortgage companies, and so on. My vehicle registration information has been sold. I've asked for them not to, but the lists go out immediately after the registration, but the "opt-out" takes up to 8 weeks, and I have to opt out of each individual VIN registered to me, I'm given no option to blanket-deny any requests under my name.
You don't have to give your information out, but life can be pretty hard if you don't. Depending on your state, you could: not hold a driver's license; not hold real property; not have a bank account; not have a credit card.
If you ever get a chance to use Lexis-Nexis, look up information on yourself. It is pretty scary what can be found. There *should* be controls on who and how they can access my private information, and the information kept on me should be available *to me* so that I can review it. Unless there are laws for this, none of the data-aggregation companies will be accountable for the information they gather.
what with fiber-optic to the home, and things like that. I mean, why bother timing how long it takes light to travel the forty-thousand miles along optic fiber?
40000 mi * 5280 ft/mi * 1.5ns/ft (approx speed of light in fiber) * 1 s/ 1e9ns * 2 = 0.63 s (round trip ping time).
You can't beat the laws of physics. (You may try to change the laws though.)
There is a metal called Nitinol, which is known as a shape memory alloy, commonly known as "muscle wires" that contract when heated. They are also low resistance conductors, so they will contract when you put current through them (and heat them up). Here's some more information. They call it "Flexinol" though. You can get small actuators, but it has limitations in that these muscles are slow, and can only "pull", they must cool down to go to their extended state, which can take some time. Also, they require a lot of current (at low voltages).
I have seen some work done with pneumatic bladders in a mesh sleeve, when they are inflated, the sleeve causes the pneumatic muscle to contract. It is called a "McKibben Actuator", here's some more information.
As the article points out, they are pretty expensive to install and you need a *large* open space to put it in. Most of these schemes exploit the fact that the earth is a pretty good heat sink and stays at a remarkably constant temperature. To maintain this, you have to have a "low impedance" path to send your heat away- which is why you need lots of land. A traditional air conditioner uses a "higher impedance" path to get rid of the excess heat, by blowing it into the atmosphere.
In some areas (like central Texas, where I live) it would be especially expensive to put in one of these systems because about 6 inches below the topsoil is limestone, which you would have to grind through and many $/foot. I'm guessing that a geothermal field like this would have to be maintained clear, like a septic field, since the roots of the plants could wreak havoc with your heat exchanger, and finding the leak would be particularly hard if the field is spread out over an acre or so. Drilling straight down can be similarly expensive.
Some areas have natural hot springs that they exploit for heat and power generation, but there aren't too many places like that.
If you can afford it, and you live in the right location, it can be great. Looking at it from a purely economic standpoint, your money is probably better spent with more traditional measures, like good insulation, high efficiency A/C, thermal windows, etc. Geothermal systems are the path of the person with a lot of money that wants to make less of an impact on the environment. But if you do this, please don't take the money you save and buy an SUV.
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If you are in any type of relatively high power RF environment, you need to go balanced- it should actually be cheaper than coax for audio, though the transformers will increase the total cost. I've worked at a couple radio stations- all professional (studio) equipment I've seen is balanced, usually 600 ohms. In a nasty EMI environment, balanced is the only way to go. Unless you are trying to make a studio with incredible S/N, you don't need to be super careful about wiring- you can get great sounding audio through punch-blocks. You do have to be careful about phase though- make sure you used polarized wire for your interconnects.
Most important: Label extensively, and take careful notes.
Theres 2 intercom lines free for you.
Using that extra pair can cause a serious drop in the performance of your Ethernet- the twisted pair/differential driver set up is pretty good at eliminating noise induced by outside sources, but only if the source of the noise is at a distance >> the spacing of the pairs. Since all 4 pairs are in the same shield, running intercom on the unused 2 pairs can interfere with the data (and vice versa). Also- you have to watch out since most Ethernet cards terminate the unused pairs into a direct short or into a 75 ohm resistor. Depending on how often you use it, it may still be acceptable, but you need to be aware that it can affect things.
Also, using the extra pairs will prevent you from running copper-gigabit ethernet, which uses all 4 pairs.
Well, really, I did try and simplify the solution, since, as posed, the solution would be underdetermined. I need more data to determine the optimal solution: the cost of the system, with a depreciation schedule, the specific MTTF and MTBF of the system, backlight replacement costs, and time, with projections into the future, including contingency plans if any of the constituent parts reaches end-of-life in the service interval. Also, I think you would have to factor in the cost of the downtime of the system with a respect to lost productivity. You could recoup some of the cost by dedicating the laptop with a dead backlight to a home server, or possibly as a tax deduction, but that is a question better posed to your accountant.
I think that this quickly changes from a failure analysis problem to an accounting problem, which takes it far out of my range of experience, which is primarily engineering.
With one or two of the lifetime lengthening measures, and without expending the effort on the PDE solution to the problem, you can probably easily extend the lifetime way past the expected lifetime of the laptop, or at least past the "crap, I spilled Coke all over my keyboard" event.
You have another concern, as detailed in this PDF. Backlight lifetime is going to go down as you increase the brightness. From a brief google search, backlight lifetimes run from 20,000 to 50,000 hours, with intensity decreasing with time, and end-of-life determined as 50% brightness of new. You may declare it too dim far before that time, but even then 20,000 hours is 2500 8 hour days, or almost seven years at 8 hours a day.
.5 to 1 hour of non-use of the system.
That gives you some options:
1. Don't run the backlight at 100% intensity- try to reduce the lighting in the areas where you are using the laptop. This saves batteries too.
2. Turn off the backlight after something like
3. If you must leave the monitor on to be able to check things at a glance, reduce the intensity as much as possible.
Also, just for the general lifetime of your laptop, use the power-down/suspend power saving features- laptops are dense little packages of electronics- which generate a lot of heat, but don't dissipate it well. Heat kills electronics and batteries, try to keep the heat down, and you will greatly improve the lifetime of the whole laptop, not just the screen. If you're not using it, and the laptop is warm, you're wasting power and laptop lifetime.
I was able to get a (photocopy of a) manual for one of my old (dead) scopes- an old Dumont 1100P- I believe they have been out of business for over 30 years. I got mine from W7FG Looking through his catalog (of photocopies), I don't see your RCA in his list, but there are a number of people like this guy who sell old manuals. Check some amateur radio sites- they're going to be the guys that have them if they are available. I don't know how they deal with the whole copyright issue...
Right out of school, a job in the government is actually pretty good. For most people, after graduating, you have a lot of theoretical knowledge, but little practical, real world knowledge, and this leads to having misconceptions about what the you really want to do with the knowledge you gained in school.
A strange thing about the government is that while they are limited in legislation as to what they can pay their employees, the same legislation gives them budgets that they must spend or get that much less for next year. In my experience, this leads to getting top of the line hardware, stuff that the private sector is drooling over, but is not willing to pay for. You can learn now on what will be the hot technology in the private sector in a few years.
Since the government pays less than the private sector, there is much more internal opportunity since they are chronically understaffed. If you want to work on a wide variety of things, the opportunity is there. My experience with the private sector, especially in big companies, is that once you have shown proficiency in a particular area, such as franistat widgets, you're more likely to be spending the rest of your career in making franistat widgets. Likely you will be very, very good at making the franistat widgets, but you may be left out in the cold once franistats are replaced by harbintrons, where you never had the opportunity to learn them.
Also, I have found that many of the people that are working for the government, especially in research, are very, very, very good at what they do, particularly those that have been at it for 20 or 30 years, and they can be a very good resource for you to learn from. Yes, there are idiots working for the government, because it is hard to fire them. In my experience, those people are easy to spot and to avoid. The people that you want to learn from are there, too. They are the people consumed in/by the technology and not jaded by the pursuit of money, status, or power. In private industry, I've found the latter much harder to find.
On the down side, the pay sucks, and promotion potential is poor. I spent 7 years working for the Federal government, 1 for the state (at a public university), and the last year in private industry. I have gotten to work on a lot of cool things, and I have a wide variety of experience. I can't say I'm completely satisfied, I do believe that I am more satisfied that I would have been if I went into private industry directly after graduation.
Bluetooth has been, and is right now, largely vaporware, though it is slowly gaining ground. The first big hurdle has been cheap, integrated chipsets, and we should have good, mass produced silicon very soon, if it isn't here already (if they are here, they've come in the past 6 months). Once the installed base is here, we'll need the infrastructure to support it, unfortunately, no-one will build the infrastructure, until there is a large installed base. When the larger infrastructure is in place, the demand will rise. Right now, we have no infrastructure, and therefore no demand. This is why the Bluetooth silicon makers have pretty much only talked to the big players in the electronics industry, like Nokia, and the big computer manufacturers. I used to work for a smaller manufacturer of devices, and the Bluetooth silicon vendors didn't want to talk to us when we were talking about paltry volumes of 10-50K units/year.
This is much like what happened with cellular phones- at first a neat gadget, but not very useful due to the lack of coverage, then better coverage, but awfully expensive, and now we are at the point where the coverage is pretty extensive and the costs can rival a landline. The demand for ubiquitous networking is growing- something will fill the gap.
At a place I used to work, used a system developed by MacLeod Technologies, the CONAC System. They used to have a web page, but I can't find it. Very small company, snd I don't know if they are in buisness anymore. Here's a PDF that has a bit of a description. A google search on CONAC gets a few more hits. It is very accurate over a limited area like a yard- it works like this: Spin a laser that has a somewhat fan shaped beam, with the axis of the fan vertical, and sweeping 360 degrees of azimuth. Place (laser) recievers at known, fixed locations around the perimeter of the area. When the laser sweeps over a beacon, record the time. The time betwwen each reciever responding will give you azimuth to each reciver. If you have a reciever on the robot itself, you know which direction your robot is pointing, in relation to the array of recievers. With all this information, you can derive position and azimuth of your robot.
Make sure you have >> 3 recievers so you can have an overdetermined solution, so that if one reciever is blocked by a person, tree, or errant butterfly, you can still determine the position.
This *does* work, as long as you don't get too far from the sensors. The farther the sensor is away, the less accurate the position solution. You might want to implement multiple sorts of sensors, including compass and whatever else you can, and feed them all as inputs to a Kalman filter, which should give you a more robust solution.
If you'd like to talk about this, de-obfuscate, and drop me an email. I'd love to have a system like this for my *own* lawn.
Assembly is very much alive and well with microcontrollers, especially the 8 bit micros (PIC, AVR, Scenix/Ubicomm, etc.). C is making inroads, but for any sort of optimization, you still need to be able to look at the code the compiler generates and understand what it is doing. This is very important when you are trying to deal with low latency interrupts, tight timing loops, and small memory sizes.
For the most part, developing in a higher level language is faster, more robust, and a heck of a lot easier. Knowing assembly greatly enhances the understanding of what the computer is actually doing, and how the computer is doing it. If speed and size are important, do assembly. The speed on many applications is strongly limited by I/O- it doesn't make as much sense to use the considerable strength and difficulty for those type of applications, but if you're trying to do real time DSP, the speed of assembly, especially when dealing directly with fast I/O, is very valuable.
It really is a matter of using the most appropriate tool for the job. High level languages do a lot of things very well. Assembly also does many things very well. C can map very closely to assembly in some circumstances. Any sort of programming language is just a layer between your ideas and the op-codes that the computer executes. Assembly is just a bit more precise, like a surgeons scalpel, compared to the dull broadsword that is Visual Basic. Insert your own cutting implement metaphor for your favorite language.
From your comments above, I think you realize that from a purely economic basis, solar, in particular photovoltaics, don't usually make sense. On the other hand if you want to do this project just cuz you want to, have fun, and here's some thoughts.
Efficiency: PV's output DC. Virtually every appliance you have uses AC, but that doesn't mean that they won't necessarily run on DC. Incandescent light bulbs will work on DC just fine- though they are very inefficient. Pumping the output of your PV array into an inverter to generate AC is a guaranteed source of inefficieny. Try to get as much as you can running off of DC- switch to a laptop that you can charge with the PVs, rig up some lighting with efficient bright white LEDs. You'll have to give up anything that uses a transformer- since by definition, they don't work at DC, but with some creativity, you should be able to bypass wall warts and the like with a custom power supply.
DC has some other things to watch out for, especially at higher voltages- it can be more dangerous than AC- an arc has less chance to extinguish itself, so if you are switching high voltage, high current DC, you need special switches that will break an arc that is started on contact opening. Also, DC will cause your plugs and such to corrode faster, which can make high resistance connections, and possibly a fire hazard.
I myself have considered a DC system in my home for reliability reasons- I get lots of short term outages, with the occasional long term outage. With a 12V system that powers my computers, I could battery back it up, and then use a simple generator set-up to take care of the longer outages, using a lawnmower engine and a car alternator. You could use a similar system, using PV's to charge up your batteries, with an AC system to take over charging when there is not enough sunlight to do the job.
I'm an EE, I got my BSEE in '91, and my MSEE in '97 (while I was working full time). When I graduated in '91, the economy was in a downturn that really affected my chances for a job- I had two separate interviews (on-site) that said, "we had jobs when we did the on campus interview, but since then, we don't." I was a good student, good GPA, but I was being picky. I decided to concentrate on doing the things that I enjoyed, those things that I wanted to spend the rest of my life doing. I took a job that was for less pay than many of my peers (at a government research lab), but I had the opportunity to learn much more than I would have if I had gone into private industry right away. Now, I'm in demand. I have a broad set of skills that companies like, and I get to do cool shit.
If you got into engineering for the money, I feel sorry for you, you'll never feel fufilled. I don't know of any engineers that are going hungry, and only anecdotal evidence of a few that drive Ferraris. You may not be able to pull down the big bucks now, but, in truth, straight out of school, most engineers don't know their ass from a hole in the ground, and they shouldn't be making the big bucks until they can prove their worth to their company. When you graduate, you've only completed the basics for an engineering job, it will take you years more effort to become a truly great engineer. Engineering is all about getting things done with the resources available. School gave you the tools to do the job, but only real life experience will give you the practice at using those tools. You will spend the rest of your engineering career honing your skills. Right now is the time to find an experienced engineer (and technician) to work with, so you can learn to use those tools with precision, style, and creativity. There are plenty of those types of jobs available now, though they may not be as glamorous. Don't be cocky, approach every opportunity with an open mind and a willingness to listen and to learn.
There are many, many students out there that have great things on their transcripts, but have no passion for engineering. Find stuff that makes you say "Wow." In that way you will excel. Interviewers notice that, many of them will be engineers that have been on the other side of the table.
As to stability, there is no guarantee of employment with any job. If you develop indespensable skills, you will be less likely to be fired, and better able to get a new position when you want it. Right now RF and analog positions are in demand because most schools are churning out engineers that are heavily digital-oriented, and ignoring the analog portion. ('Cept for DSP.) But speeds are getting so high that analog and digital are blurring into one. There are other examples out there. The best RF engineers I know are all nearing retirement age. When they are gone, so is their knowledge. You have the opportunity to mold yourself into what is in demand, not now, but 10 years from now.
Yeah, its gotta take a lot of effort on the part of the person that needs the help too. But nobody's going to get themselves out of poverty by just waiting around. If the computer can give them the idea that they can improve their lot in life, then it succeeded. A computer in my view is just a tool. Some people know how to use it, some don't, but very few of the people who don't know how to use it can't learn.
I'd rather see them spend that money giving out computers than teaching them how to chop down the rainforest for an unsustainable farm, or to raise more cattle for McD's.
I agree that the internet is no more the answer to poverty than a library card is the answer to illiteracy. But it can help, give incentive to work for the future, rather than perpetuate the status quo. The internet is only part of the answer. Education is another very important part. The internet can give us information, but most importantly it gives us communication. Communication is an empowering technology, it enables people to see beyond their locale.
If a farmer has information about the weather, he can better plan his planting and harvesting. A factory worker can search for a better job. A merchant can search for the best wholesaler for the wares he sells. A craftsman can find out how much the things he creates are actually worth, and price them accordingly, rather than trust the middleman who only has his own bottom line in mind.
If you're going to give the poverty stricken anything, give them opportunity. That's what this cheap internet terminal can give. Viewing a computer as a luxury relegates the computer to the level of television, a one way medium. But the real power of the internet is that even though the bandwidth is largely one way (to the user) there is still a channel out (to the world). You can just spectate, but you have the opportunity to participate, and it is up to the individual to choose.
I guess I can't fully convince you yet, but I do know one thing for sure, the capability to do this has to be built with hardware first, before the software would be able to use it. That hardware is available right now- since wake-on-lan is becoming popular. Manufacturers are building it into products right now. If there was not a demonstrated need, they wouldn't be. As to software that supports that... I dunno, I'm a hardware guy.
History has proven that software will be written that will fill the needs that present themselves. If it isn't available now, it will be.
Energy savings just for the sake of the environment don't take off quickly, but if there is money to be saved, stand back, it's gonna happen.
I guess the real question I've got is this: Why would you want your server to sleep?
Pretty simple, really- lets say you're using load balancing, and to handle your peak load, and you need 20 servers, but at off peak times, you only need 25% of the capacity, 5 servers. If you can shut down the other 15, you would have about a 75% power savings during off-peak times. This is especially the case if the market you are serving is reigonal.
Since we're talking about servers here, anyone who is running a bunch of servers without a KVM (keyboard, video, mouse) switch is pretty foolish. With a KVM you need only one monitor for a whole raft of servers. The technology is improving, there is at least one company that is sending all the KVM info from the servers to the switch via a single dedicated Cat5/RJ45 cable (per machine).
Hooking this up to a flat panel monitor would save power, of course.
The KVM is nice for when you need to have access to the console, but if you can handle a headless server, an xterm is even nicer (as long as you are running a Unix variant).
As to a flat panel being cheaper in the long run... my 21" monitor is rated at about 200W, if a comparable flat panel draws 30% of that, or 60W. I'll assume an (outrageous) rate of $0.50/kWh. It costs about $0.10/hr to run the CRT, and $0.03/hr to run the FPD, a savings of $0.07/hr. Pricewatch gives me about $500 for a cheap 21", and $1300 for a cheap 18" FPD, an $800 price difference. You would have to run your monitors for about 11,500 hours for the price of the FPD to beat the CRT. If you work 10hr/day, 5 days a week,(and turn the monitor off when you're not there) it would take almost 4.5 years for the FPD to pay for itself. I'm not exactly sure of the California electricity rates- I encourage someone who has better numbers to correct mine.
At a more typical rate of $0.10/kWh, it costs $0.02/hr for the CRT and $0.006/hr for the FPD, it would take 57,000 hours, or almost 22 years for the FPD to pay for itself.
Flat panels are nice, but, I think you're going to need another arguement to convince your boss.
As previously reported, what's going to happen to the broadband adapter now that they're clearing out inventory? Looking at the Sega store listing, it is classified as backordered. Will they be filling those orders? Will it be available somewhere else (other than ebay)?
Sadly but ture, the faster and faster processors that we get, the lazier and lazier the coders get
Absolutely. Those are the hacks of the programming world, but there will always be a small subset of people who will create tight efficient code. Many programmers opt to make sloppy, inefficient code because they can get it out quickly without a heck of a lot of theory. Those that do will continue to make mediocre code. But that will be for mundane tasks. There is plenty of mundane code that needs to be written. I, for one, would prefer to have the best of the best programmers working on the tough problems, not relegated to the run-of-the-mill problems because nobody else can produce something workable.
There are plenty of applications that require more computing power than we have commonly available now- like real time image recognition, real time speech (as spoken) recognition, photorealistic image rendering. This type of problem is where our best programmers should be working.
Heck, the advent of Linux showed us that we could still do great things with a 386 when the 486 was all the rage. As we get more computing power, the realm of the possible will continue to expand.
...the more we keep discussing this, the more we agree...
There is one point where we disagree-- What I would like to see, which would be a huge change in the way we think about our private data, is that, by default, all private information is private. If there is any personally identifiable information (name, address, SSN, etc.), it would automatically be deemed private. It could be collected without explicit permissions of the "owner" of the data, but it could not be distributed without the permission of the "owner." If you can't gain the permission of the owner? You can't distribute it.
I have some difficulty with the panhandler analogy: once I give money away, really, I have no say. I would like to know that my money is going to food and shelter rather than Maddog and Marlboros, but I have no say. Enough pennies will make a million dollars... This data can be aggregated to something much more valuable. It is about data security- when I used to work with classified data, we got annual briefings on OPSEC -Operational Security- which basically meant, keep everything to yourself, because you want to deny "the enemy" any sort of information advantage. Something you may think is trivial may be the key to tying together a whole raft of data. Enough generic demographic data can zoom right in on an individual. I want to be able to trust who I give my information to, and make sure they don't use it against my wishes. There does need to be some higher controlling authority- and in this case it is the government.
Can it happen? I don't know. Making and enforcing these provisions would be daunting, but I think it is the direction we ought to go towards, less will be equivalent to no privacy at all. Data storage and processing power keeps getting cheaper, without some restriction on the collection and sharing of personally identifiable information, there eventually will be no such thing as privacy.
(Whoowhee, I'm sounding like a real zealot. Guess I ought to go back to my cabin and finish my manifesto.)
My major peeve, as stated above, is that we're setting the fox to guard the henhouse. We should at least hobble the fox first.
Absolutely. As a citizen of a country, we have a right to at least try to affect the policies of the government. Unless you're a shareholder in a company, you don't have any grounds to ask a company to restrain itself. If you're not, you can ask, but they have every right to ignore you.
Or, consider this it boils down to who "owns" that information- My private information is mine- I should retain ownership, and from that, control. If I give it to you, you can use it, but you should have no right to distribute it further, unless I grant you that right.
But this makes me wonder, What are the negative results of restricting my private information? I might miss some direct mail, I might miss out on some unsolicited credit card offers. What else? Has this been touched on elsewhere in this article's discussion?
Note that the examples you've listed are all examples of governmental agencies selling your info.
True, but the companies to keep our eyes on are the private corporations buying that information and selling the data about us. They can aggregate it, correlate different information and come to their own conclusions. This aggregation is what "data mining" is all about. What if the database is screwed up? Will you be able to find out before it screws up your life? You miss out on a job? You miss out on a home loan? There are mechanisms to correct mistakes, but they are universally slow.
Once it leaves the government's hands, they have lost all control. All government agencies are accountable, for the most part, (ultimately) to the citizens of that country. (Yes, I know there are major exceptions.) If there is enough uproar (as there was a few years back about driver's license records, which enabled a stalker to find, and ultimately murder, a sit-com actress) the government will change its laws.
A company is only accountable to its shareholders. If the company runs afoul of the law, and is punished, ultimately the shareholders pay the cost. That company has no obligation to the public, other than to obey the law.
Right now, privacy is being treated as an opt-out process- I would prefer if it was, by default, opt-in. Since we don't necessarily know all the data that is collected about us, I want all information about me to be considered private, and let me decide what is to be made public.
If a private company wants to distribute it, they should have to tell me what information they are selling and to whom. I would prefer it if my state would not distribute this information, but ultimately, it will have to be a federal action that forces privacy. As it stands now, if it is not expressly prohibited, it is permitted.
(to be truthful, it appears that for the most part, we agree, unless, I'm being particularly dense and failing to catch on to your irony)
If you don't give your info out, people don't have it. If you don't specify that it be kept confidential, it won't be, nor should it be.
Much easier said than done. Some things can't be kept out of the public record- such as deed information- I've bought 2 houses, and I have no choice but to have that information available. I don't mind if the local public utility uses it to send me a letter informing me of something they have to do in the right-of-way. On the other hand, this same database is *SOLD* by the state (I'm in the USA) to direct mailers, Mortgage companies, and so on. My vehicle registration information has been sold. I've asked for them not to, but the lists go out immediately after the registration, but the "opt-out" takes up to 8 weeks, and I have to opt out of each individual VIN registered to me, I'm given no option to blanket-deny any requests under my name.
You don't have to give your information out, but life can be pretty hard if you don't. Depending on your state, you could: not hold a driver's license; not hold real property; not have a bank account; not have a credit card.
If you ever get a chance to use Lexis-Nexis, look up information on yourself. It is pretty scary what can be found. There *should* be controls on who and how they can access my private information, and the information kept on me should be available *to me* so that I can review it. Unless there are laws for this, none of the data-aggregation companies will be accountable for the information they gather.
what with fiber-optic to the home, and things like that. I mean, why bother timing how long it takes light to travel the forty-thousand miles along optic fiber?
40000 mi * 5280 ft/mi * 1.5ns/ft (approx speed of light in fiber) * 1 s/ 1e9ns * 2 = 0.63 s (round trip ping time).
You can't beat the laws of physics. (You may try to change the laws though.)
There is a metal called Nitinol, which is known as a shape memory alloy, commonly known as "muscle wires" that contract when heated. They are also low resistance conductors, so they will contract when you put current through them (and heat them up). Here's some more information. They call it "Flexinol" though. You can get small actuators, but it has limitations in that these muscles are slow, and can only "pull", they must cool down to go to their extended state, which can take some time. Also, they require a lot of current (at low voltages).
I have seen some work done with pneumatic bladders in a mesh sleeve, when they are inflated, the sleeve causes the pneumatic muscle to contract. It is called a "McKibben Actuator", here's some more information.
As the article points out, they are pretty expensive to install and you need a *large* open space to put it in. Most of these schemes exploit the fact that the earth is a pretty good heat sink and stays at a remarkably constant temperature. To maintain this, you have to have a "low impedance" path to send your heat away- which is why you need lots of land. A traditional air conditioner uses a "higher impedance" path to get rid of the excess heat, by blowing it into the atmosphere.
In some areas (like central Texas, where I live) it would be especially expensive to put in one of these systems because about 6 inches below the topsoil is limestone, which you would have to grind through and many $/foot. I'm guessing that a geothermal field like this would have to be maintained clear, like a septic field, since the roots of the plants could wreak havoc with your heat exchanger, and finding the leak would be particularly hard if the field is spread out over an acre or so. Drilling straight down can be similarly expensive.
Some areas have natural hot springs that they exploit for heat and power generation, but there aren't too many places like that.
If you can afford it, and you live in the right location, it can be great. Looking at it from a purely economic standpoint, your money is probably better spent with more traditional measures, like good insulation, high efficiency A/C, thermal windows, etc. Geothermal systems are the path of the person with a lot of money that wants to make less of an impact on the environment. But if you do this, please don't take the money you save and buy an SUV.