Has anyone ever taken apart (or seen the inside) of a big screen TV? Do any of you youngins remember the old big screens from the 70's and early 80's?
The picture display tubes used in typical big screen TV's are in reality nothing more than liquid cooled versions of the tube used in a typical TV. These tubes are liquid cooled (on the front - it is a passive cooling - think of using water as a heat sink, with no pump) because they are driven to insane brightness levels (way brighter than maximum brightness on a normal TV set), to get the picture as clear as possible in the final result. Furthermore, most big screen systems use three tubes, one red, one blue, and one green (they are black and white tubes with filters - not unlike stage gels), each aimed and focused separately to get the highest resolution picture possible (this seperate aiming, etc is one reason why you should have your big-screen adjusted after moving it - even if it is across the room). HDTV sets merely use ultra high-res SVGA tube systems to get the resolution needed.
After that step, it is simple optics - most of the time no more than one or two largish glass lenses (with anti-chomatic aberation built in) and a mirror or two to flip and reverse the image - sometimes the image is projected inverted and reversed and bounced off of one mirror to get the final image. The idea is to get the projection as near parallel with the screen as possible. Where that isn't possible (due to the size of the cabinet), special lenses are added (or it is done electronically) to "keystone" the image in the proper direction so that it comes out "square" in the end.
That is all - amazing, isn't it, that one would pay almost 2000 bucks for a few TV sets, some wood , and some optics? Well, you do get a better quality system, and the optics are top notch, too - plus, the TV sets are anything but normal...
What these 100 inch plans and systems try to do is do all of that on the cheap - a light tight box is built around the TV set, a fresnel lens is added (it is a cheap lens), and you turn the TV set upside down and add a mirror to reverse the image. Typically, you might also crank the brightness up to get a slightly better image for the larger 100 inch displays.
What does this get you? Actually, if you do everything perfectly (and watch out turning that set upside down - sometime the magnetic field of the earth screws things up, and you need to degauss the set to recover in the upside down mode), have it all aligned, use a good fresnel lens, a good lighttight, square, painted black inside box with a nice mirror, and you use a larger set (15-19"), and a good projection surface (not a sheet - not enough reflection - ideally, you want a silver beaded projection screen, for maximum gain - but since it would be stupid to spend $150 on a screen for a $10 big screen, there are alternatives, more on that later) - you can get a reasonable image. You will have to turn out the lights, and let your eyes adjust - but you will get a watchable image. It isn't a scam. The edges will tend to be fuzzy, though, because a fresnel lens isn't a perfect lens, and has focus issues at the edges. Put a black border around your projection surface to mask these off, and things don't look too bad. Also, don't try to go for a 100" display - try a 40" display first, and adject until you are happy with pixel size and clarity. It is possible to make it look damn good, good enough for most entertainment uses.
Now, want to know how to make a better projection TV system (though this time, it will cost a bit - more than $10, but less than $500)?
LCD projection systems are really systems designed to rip the gullible off. At least with CRT projection, the manufacturers have an out with the special CRTs and optics they use. LCD projectors, though, are the simplest of them all (note, DLP projectors are not LCD projectors, so I can forgive their cost) - it is crazy that they sell these ultra expensive projectors that are nothing more that glorified slide projectors...
That's right! Slide projectors! The optics and light system are the same (nearly equal) as to what is in an "old-time" slide projector - the slide now is an LCD panel! This panel is typically rather small for it's resolution - but this doesn't excuse the cost, because LCD production quality is supposed to go up as the size goes down, and the price is supposed to go down as well, right? Well, it hasn't - at least I don't know where I can get a $150.00 800x600 LCD projector yet, which typically uses a smaller LCD display (less than 2" diagonal). Anyhow - all one has to do to build their own LCD projector is to get an LCD about the size of a slide, and drop it in place of the slide in a slide projector (which can be bought cheap off of Ebay). This kind of projector system was first described by Robin Cook in his book "The Virtual Reality Homebrewer's Handbook". One thing he recommended was to use a fan to cool the LCD, because the projection lamp could overheat the LCD, causing it to shut down or burn out. What is used for the LCD? Why, an LCD TV, of course - you take one apart, remove the backlight (because the projection bulb will be your backlight), and put the screen in place of the slide in an old slide projector. You also need to re-route the electronics and cabling, but it can be done. Also, try to use a TV with a TFT display for clearest moving images. It is also possible to scale this up by using larger LCD displays (various electronics surplus dealers sell $99.00 4 inch LCD displays for use in in-car video systems), and a custom lens/projection system. A larger LCD will give a clearer image.
Now, what will be the quality of such a system? All I can compare it to is a device I have, that works the same way, and is how I got my "Big Screen" experience cheap. I own a Fujix P401 LCD projector - cost me $250.00 a few years ago, and gives me an "OK" picture. I can comfortably display X on it if I use a 640x480 setting - some things are readable - but mostly I watch VCDs on it (using mtvp - anyone know of an equal Free replacement to mtvp?). Higher res images can be displayed, but they are fuzzy, at best. I would imagine a homebrew system to be comparable to this, possibly better.
Now, would it be possible to reproduce a three tube CRT system? Of course! You could build three of the 100" systems, but use black and white sets with colored pieces of plexiglas (or stage gels) in front of them. It would be a little bulky, though. I could imagine gutting some small (9" or smaller) portables to do this, and building a custom cabinet. Another possibility is to get (through various electronics surplus retailers on the net) surplus big-screen optics (which shouldn't cost more than $25.00/ea), and put them in front of the CRTs you are using. This would result in a more compact system (especially if you removed the casing of the TVs - be careful of the high-voltage inside, though - one hand in pocket when poking around inside those sets!!!).
Now, what to use for the projection screen - well, since you are doing this on the cheap, you can't very well buy a nice screen - they can be expensive. However, sometimes you can get a used silver projection screen fairly cheap (under $50.00 sometimes on Ebay, less at garage sales) - but make sure it is good quality. Most of these are tripod style, and don't have a ratchet mechanism to allow a "pull-down-from-ceiling" setup, that is much more enjoyable. To solve this, use what I used: A pure-white blackout shade. These can be found at Home Depot, and they can be had for ultra-cheap prices (less than $30.00 for the largest size). You can build mounts by using some bolts and a couple of bookshelf brackets, with careful setup, a pull down system is easy (I had mine together in an hour). These shades are smooth, have a high reflectivity, and are very inexpensive. Another alternative is high reflectivity white paint on a board. You can also use a white vinyl shower curtain, stretched tight. There are numerous options. Just look around and imagine.
Finally, I want to tell you what I used to display X under Linux on a TV (or projection system with composite input, like these homebrew projectors use). There is a device called the Averkey iMicro that is a true plug-and-play system. Pop it into your VGA port, load up X, and it will recognize the settings - no need to mess around with your XF86config settings (unless you need a certain res) - high-res, low-res - don't matter - it can recognise it. And it gives a great image, and it is cheap (around $100). I highly recommend this product.
OK - now you know the scoop. I hope this long, long comment will help someone. Realize that you won't get the be-all and end-all of projection images with these systems. However, I don't think they are a scam - in reality, they are selling the lens and some plans, and true, as good or better plans could be found on-line. But people are lazy, so I tend to think that they are selling a lens, some plans, and the cost of research - for $10.00 or less in many cases, that isn't a bad deal. I tend to wonder if I compiled all the info I had onto a CD, and sold that with a lens, if I could make some cash - but I am lazy, so if someone else wants to take a stab at it, go for it!!!
While I find it hard to imagine someone actually doing this, the idea of building a fishtank-style clean-room and actually using it for this sort of operation does appeal to me.
I can imagine doing it completely off-the-shelf, by building a working envelope with plexiglas and silicone sealant, hooking up two over-large dish gloves (or surgical gloves) with extended cuffs for mobility, and a HEPA filtration system providing a positive pressure feed. Most of the components could be purchased at Walmart.
Actually using it would be interesting for crazy operations like you outline - last resort efforts of the Nth kind. Makes me wonder if any person or group has actually done such a thing...
OK, here is an idea on how to "build" electric boots. I am giving it away free, to the public domain. Hell, it might already be patented, I don't know...
Build a boot with a fairly rigid upper, or with a frame around the upper, in such a manner that there is a semi-flexible pivot and a fully flexible pivot around the ankle (in other words, make it flexible in the full range of motion of the ankle, but try to keep it mostly flexible in the "normal" direction of motion, in line with the rest of the leg.
Around this pivot you would need a gear system, with maybe a ratchet and small flywheel system (like the baycomm radio), so that as the ankle flexes, the flywheel is spun at a high rate of speed. Perhaps even make it spring loaded, so that when standing still, or during mid-stride, the flywheel continues to run for a short while.
Attach a small generator (one of those cheesy 3V motors would be perfect if made a bit more robust), and tap the power.
Feasible? Sounds reasonable to me, though perhaps a little bulky - but I bet with good design, it could be slimmed down and made to work rather well...
Finally, Handspring has done it before everyone else
A coworker of mine currently has (and has had for over a month) a combo cell-phone and Palm III PDA after he got tired of his separate cell-phone and Palm V.
He said he got it from AT&T, I believe - I don't know if it has the whole POP3 email thing, but it is a combo unit.
The Palm forms part of the screen, and the microphone flips down revealing the full thing, and I think a keypad underneath for dialing. It actually isn't a bad integration, though it is a little wide.
I checked on AT&T's website for it though, no dice - maybe it is discontinued?
I sent the following email to one of my senators, John Kyl:
Dear John,
Thank you for passing today an act (USA Act) that helps destroy our fourth amendment - an amendment to the very Constitution you swore to uphold when you took office.
Why must the rights of American citizens be violated for our so-called "safety"?
I am not a senator, something which I would like to think takes great logic and analytical skills, as well as strong morals. But this does not seem to be the case, as you apparently do not understand that SAFETY IS AN ILLUSION. Laws exist to help keep that illusion in place, but once
again, laws themselves are illusions.
The government can not protect me. I do not harbor such illusions. I, myself only, am the only one capable of providing for MY protection.
As a constituent, I look forward to your running for office again.
So I CAN VOTE YOU OUT.
Sincerely,
I sent it using the address "info@kyl.senate.gov", which I found in the FORM code in the page source at http://www.senate.gov/~kyl/con_form.htm
I sent it via normal email, because I also cc'ed the email to our other John, John McCain, so I didn't use the form.
Fat lot of good it would have done me anyway, because here is the form response I got back:
Thank you for writing to me at info@kyl.senate.gov. In an effort to respond as quickly and thoroughly as possible, I am no longer receiving e-mail at this address. I have chosen instead to use a new web-based system that allows me to quickly review the thousands of e-mails I receive and give priority to those from my constituents in Arizona.
There is more, but it is long - suffice to say that the reply went on to note that I should go to the site and the reply form that I had went to originally to get the address!
This is utter bull! I used the address used in the form, and it is an invalid address! So even if I used the reply form, it wouldn't go to him! Am I right on this, or wrong? This is the way it seems. I suppose the CGI could email it elsewhere, but why is the mailto var set to that email address?
True - but as others have pointed out, these dates have the ability to be renewed. Other posters have pointed out that Britain has had "temporary" anti-terrorism laws on the books for over 20 years, simply because the "sunshine clause" keeps getting moved further back.
What is the point of "sunshine clauses" if the sun never rises?
The sphere is connected to the driveshaft. The sphere therefore rotates. If the wobbly plate was attached to the sphere, it would have to rotate as well. However, the metal vane is stationary (held in place by a slot in the two cones), and the wobbly plate is flat against that vane, so it can't rotate, and would therefore not be attached to the sphere.
This is what the animations seem to show.
The only other possible explanation would be that the shaft passes through the sphere, and is connected to the conical ends only, and the the sphere is "free-floating" to an extent, and that the wobbly plate and the vane rotate around everything. However, the animations do not show this, but instead shows the cones (which hold the glow plugs, etc) and the vane to be stationary.
I hope that clears up my explanation. Please remember, though, that I could be wrong in all or part of it. I am merely basing my explanation on a couple of gif animations and a few explanations from the article and website...
Many posters are stating that they either don't hear from their representatives, or they get back form letters - which basically is an acknowledgment of them receiving your letter, but not whether it was read or cared about.
Very few posters have stated they have gotten real non-form letters back. I know on occasion I have gotten ones back, but it has been a rare occasion.
If our representatives are not listening, then do we truely have representation? We are still being taxed, I see that every day. But we seem to have no representation.
I seem to recall something from my history books about a war being fought a while back over "taxation without representation" - or maybe I am mistaken...
I sent an email yesterday to Feingold in WI. I live in Arizona. The email I sent him was a "good job" type email, and wishing he worked here, and thanking him for his work on behalf of American citizens everywhere.
I included my address, though I doubt I will get any response back (not that I am looking for one).
By your statements, my email got tossed - even though it wasn't a complaint!
Why are our representatives so backward about this stuff. This isn't the future we are talking about, this is the present! It would be like ignoring telephones or faxes (which they apparently still do on the latter).
If they have expirations, they better be hard and fast expirations, and not something along the lines of "When the war is over" or similar.
Note: we are not officially at War! Congress has not declared War!
BTW, if they word it to expire when "the terrorist threat is mitigated" (or some other similar wording) - how do you decide that? Terrorism is not something that will "magically" go away. It has been with human society since the first stick or rock was brandished as a weapon!!! Such wording will do nothing as a "sunshine clause"!
This "war" is as much a "war" as the "war" on (some) drugs is a "war".
Congress has yet to declare War. I do not consider the United States at War until Congress declares war. The President does not, and has never, had this power - only Congress has this power. As of yet they have not exercised it. Yet they are rapidly declaring that the Constitution needs to be shredded (which you understand is happening). Such radical changes to the Constitution means something is falling apart - something is happening - and it must be real, capital "W" - WAR!
Why hasn't Congress declared War? Could it be that such acts as the USA Act would require a sunshine clause should War be declared - that is, that such acts would have to be rolled back once the War was over? Could it be that this so-called "war" can't be really won, and thus it can't be legitimately called a War? Thus, a sunshine clause would not help, since there would be no end? Or that if it can't be won, then a declaration of War would be a declaration of a perpetual War? Could it be that if we declare War, then the USA would be bound by various conventions (Geneva, etc) regarding War and POWs, etc?
WTF is going on - this is crazy - why isn't anyone outside of/. giving a flying fuck? Hell, the various news sources are reporting it, yet none of them are discussing it - I would be up in arms, so to speak, if I had to report this on camera and in the paper or on the net.
I fear the day is dark, and getting darker by the minute. True, the sun still shines, but it means nothing if these shackles are being secured to my body...
I agree - there should be video out, if for nothing more than to bring up the playlist, etc on your TV (which will probably be near your stereo), as well as to add some visualization eye candy for the next party you throw...
I have read a lot of posts here regarding this engine, and I am not absolutely certain that everybody understands how this engine is supposed to work. To be honest, I am not completely certain on how it works, but from looking at the animations and descriptions, I want to attempt to explain it, in the interest of furthering discussion.
I have to admit, the fascinating thing is the fact that it is so simple - so simple that it looks like it could almost be homebrewed in a garage, provided the builder has sufficient machining skills and tools (ie, a metal lathe and mill would be an absolute necessity, as well as a wire-feed welder, among other tools).
Anyway, here is my explanation:
1. The engine is composed primarily of 6 parts: A shaft (1) which is fitted through a sphere (2) and two opposing, on either sides of the sphere, conical ends (3,4), a metal vane (5) which is slotted between the cones, and thus doesn't move - parallel to the shaft/sphere assembly, and perpendicular to the metal vane. Finally, there is the wobbly plate (6), which is fitted around the sphere, and has flattened ends that are up against the metal vane. This plate bisects the sphere, forming two independent combustion chambers. However, it is not attached to the sphere, it does not rotate, and it is not attached to the vane. It merely "slides" against these parts.
2. Now, imagine the metal vane lying at an angle. At the point where one end is touching the cone, and the vane, there is a fuel inlet and a glow plug. Fuel is admitted, and the glow-plug ignites the fuel.
3. As the fuel combusts, it expands, pushing against the plate and the vane, as it races around the chamber, which looks like a expanding wrapped wedge around the sphere. This expansion causes the plate the nutate (wobble) - but not rotate - around ("around" is not a good word, as it implies that the plate is rotating - I must stress that it does not rotate) the sphere. This opens up the chamber, and as the plate slides around the sphere (*), it rotates the sphere 180 degrees, which is connected to the shaft, which turns the shaft 180 degrees.
4. Once the combustion is started, of course the fuel inlet is closed. When the combustion is completed, the plate is now lying at the opposite angle. An exhaust port is opened (I would imagine the opening and closing of exhaust and inlet ports to be accomplished by solenoid valves of some sort), and the inlet port on the other side is opened to cause the other side to fire, to rotate the shaft 180 degrees more, while simultaneously pushing the exhaust out (by action of the plate) on the opposite side.
5. The cycle repeats.
(*) - Notice how many parts are sliding against each other? I can't understand how this thing is supposed to run dry - ie, no lubricant - unless the fuel is to provide the lubrication of some sort. All that friction will get it damn hot if it isn't lubricated and cooled in some manner.
Furthermore, I am not certain how the plate, rubbing up and acting on the sphere (nutating "around") spins the sphere, unless is it by some strange vector motions being imparted by friction.
The interesting thing about this, though - is if that is the case, if the motor shaft is somehow stalled for whatever reason, the engine shouldn't die - it should only become hotter than normal, which may or may not be a good feature.
---
I hope this explanation helps - I hope it is right, I am pretty certain it is. Please discuss below, and comment on it - I would be pleased to know what others think...
It uses a steel belt, composed of what appears to be a lot of parts (supposedly high-strength parts). In a go-cart, similar systems are used, but use a funky shaped "v" belt (it isn't a true V shape).
I do have to say if that belt did break, it would probably be a mess...
The wobbly plate does not spin - there is a stationary vane on one side fitted into slots on the cones. The plate appears to wobble because it is fired on one side of where the plate and the cone and the stationary vane come together. As the explosion expands and progresses, it causes the plate to move and wobble. I am not sure how this gets the sphere spinning, though, unless just by frictional contact and through various motion vectors the sphere moves.
I would still think all of this would need severe lubrication and tight tolerances...
Are you speaking of the McMaster engine, or the quasi-turbine (they are two separate designs)? If it is the former, please provide a link - if it is the latter, then I am wondering this too, but I have to investigate further...
BTW - wasn't the Wankle engine's combustion chamber cardoid shaped, not peanut shaped?
Take a piece of plywood. Cut a hole, mount a speaker on the front. Now, build a plastic/rubber bladder/balloon to attach to the sides, so that your now have a "box shape" - optionally with side "arms" to hold the edges forming the sides ridged. Add a valve and pump it up.
In other words, the bladder forms the structure to hold the speaker up, and the plywood panel serves to have a place to mount the speaker.
Bet I know what it sounds like, too - CRAP! This is basically a "boxless" or "baffless" design - where the panel is just a speaker mounting point, not much else (keeps a little sound from radiating forward). Grab a speaker design book from the 50s, early 60s, and you will see this design. Even then it sucked, just not as bad because speakers in general weren't that great.
These "blow-up" speakers might be OK if the bladder is of a sufficiently thick material, and it is kept at a high pressure level, but they won't be "great"...
I stopped playing with it a couple of years back. The things I keep waiting for is:
Trees Sunlight thru clouds
One other thing I would love to see (any possibility of?) is a Linux/X port. Basically, since you have the C++ stuff taken care of, most of it would be a UI interface, right (using GTK or some similar lib for that would work)?
Build a large steel cabinet, using.25 inch steel plate. Add ventilation holes. Put the computer inside, maybe with a UPS as well. Run cables out of it via romex sheathing to power and monitor, and weld the romex to the box. DO NOT hook up any printer or modem - or if you do, place it in the box with the computer.
Create a wireless IR keyboard interface, with one of those mini keyboards - plus possibly custom software drivers and/or hardware interfaces for it. Provide a hole so that the IR x/r unit can "see" out of the box to the keyboard.
Lock the box up in some manner - tack welding might be preferable. Add a power switch to the outside of the box, maybe a few status LEDs.
Take the keyboard with you whenever you are not with the machine. Perhaps sleep with it under your pillow, or put it in a safe under your bed or something. Follow the rule about using epoxy on the screws. Maybe put seals over the welds, or take pictures of the welds to compare with every now and then (say once a week). You might even want to place the monitor in a copper wire mesh bag or Faraday cage, propely sealed and grounded for stray RF emmisions. Maybe not even provide a modem, only a floppy drive of some sort - and do all decryption of that secured machine. Won't stop "them" from tracking who/when you comm with other parties (ie, traffic analysis), but will keep them from logging you.
If you are truely needing this, you will see that what I suggest is actually worthwhile...
Generating a simple fractal landscape is both an easy and a difficult process. The algorithm is relatively easy - it is the implementation that can be difficult.
It is possible to implement a fractal landscape generation system on using only 2D graphics, which produce an image that looks amazingly 3D in scope, but isn't. Of course, it is possible to do the same algorithm in a 3D coordinate system.
I came across the 2D method first in an old Creative Computing article from around 1983 (the issue was the "graphics" issue, and in addition to the fractal mountain code done in BASIC for a couple of systems, there was an article that detailed making photo masks and combining computer graphics and real photo techniques to produce cool effects for the time - today, photoshop works wonders). The BASIC code was for a PCjr (IIRC) and an Apple IIe, but I converted it to my TRS-80 Color Computer - and it ran fine (though very slowly).
Essentially, the process is:
1. Select three random (X,Y) points on the screen - these form the "base" triangle. 2. Find the midpoints of each side of the base triangle. Split each side in half (subdivide it), and move the midpoint up/down by a small random amount (in the Y direction on screen), and join the points - the deformed triangle should now be composed of 4 sub-triangles. 3. Repeat the process on each of the resulting sub-triangles n-times.
Of course, n tends to be a small number - around 7-10, depending on the resolution of your output device. There is also a way to add "water" by deciding on an certain "Y" level to disallow drawing of "land", instead showing "water" (where "land" is green, brown, or grey, and "water" is blue).
That's the basic algorithm, and the hard part is keeping all the sub-triangle's vertices joined, so that when one is shifted up, the adjoining triangle's vertex shifts up as well. In the Creative Computing article, this was accomplished with arrays and really complex code that wasn't explained too well. Today, you would probably use a combination of linked-lists of objects (where each object represents a vertex), and of course a recursive function system. It would end up being more of a memory hog, but it would be easier to code as well.
Taking the algorithm into the 3rd dimension would be easy, since you would plot the base triangle on the X/Z (or X/Y) plane, then as you went through the subdivision process, you would simply change the height of each vertex in the Y (or Z) plane respectively.
I have to agree with you AC, that Terragen is very impressive.
Want to know what is more impressive about it?
It is written mostly in Visual Basic (don't believe me? Email the author. I found out after having a conversation with him about using VB for 3D stuff like this a few years ago, because I noticed it installing the VB runtime during setup).
Slashdot Mirror
Not sure if it will help - you may have already seen it (watch, it will be your site):
k s/
http://www.seanet.com/dsl/Covad/EfficientNetwor
Has anyone ever taken apart (or seen the inside) of a big screen TV? Do any of you youngins remember the old big screens from the 70's and early 80's?
The picture display tubes used in typical big screen TV's are in reality nothing more than liquid cooled versions of the tube used in a typical TV. These tubes are liquid cooled (on the front - it is a passive cooling - think of using water as a heat sink, with no pump) because they are driven to insane brightness levels (way brighter than maximum brightness on a normal TV set), to get the picture as clear as possible in the final result. Furthermore, most big screen systems use three tubes, one red, one blue, and one green (they are black and white tubes with filters - not unlike stage gels), each aimed and focused separately to get the highest resolution picture possible (this seperate aiming, etc is one reason why you should have your big-screen adjusted after moving it - even if it is across the room). HDTV sets merely use ultra high-res SVGA tube systems to get the resolution needed.
After that step, it is simple optics - most of the time no more than one or two largish glass lenses (with anti-chomatic aberation built in) and a mirror or two to flip and reverse the image - sometimes the image is projected inverted and reversed and bounced off of one mirror to get the final image. The idea is to get the projection as near parallel with the screen as possible. Where that isn't possible (due to the size of the cabinet), special lenses are added (or it is done electronically) to "keystone" the image in the proper direction so that it comes out "square" in the end.
That is all - amazing, isn't it, that one would pay almost 2000 bucks for a few TV sets, some wood , and some optics? Well, you do get a better quality system, and the optics are top notch, too - plus, the TV sets are anything but normal...
What these 100 inch plans and systems try to do is do all of that on the cheap - a light tight box is built around the TV set, a fresnel lens is added (it is a cheap lens), and you turn the TV set upside down and add a mirror to reverse the image. Typically, you might also crank the brightness up to get a slightly better image for the larger 100 inch displays.
What does this get you? Actually, if you do everything perfectly (and watch out turning that set upside down - sometime the magnetic field of the earth screws things up, and you need to degauss the set to recover in the upside down mode), have it all aligned, use a good fresnel lens, a good lighttight, square, painted black inside box with a nice mirror, and you use a larger set (15-19"), and a good projection surface (not a sheet - not enough reflection - ideally, you want a silver beaded projection screen, for maximum gain - but since it would be stupid to spend $150 on a screen for a $10 big screen, there are alternatives, more on that later) - you can get a reasonable image. You will have to turn out the lights, and let your eyes adjust - but you will get a watchable image. It isn't a scam. The edges will tend to be fuzzy, though, because a fresnel lens isn't a perfect lens, and has focus issues at the edges. Put a black border around your projection surface to mask these off, and things don't look too bad. Also, don't try to go for a 100" display - try a 40" display first, and adject until you are happy with pixel size and clarity. It is possible to make it look damn good, good enough for most entertainment uses.
Now, want to know how to make a better projection TV system (though this time, it will cost a bit - more than $10, but less than $500)?
LCD projection systems are really systems designed to rip the gullible off. At least with CRT projection, the manufacturers have an out with the special CRTs and optics they use. LCD projectors, though, are the simplest of them all (note, DLP projectors are not LCD projectors, so I can forgive their cost) - it is crazy that they sell these ultra expensive projectors that are nothing more that glorified slide projectors...
That's right! Slide projectors! The optics and light system are the same (nearly equal) as to what is in an "old-time" slide projector - the slide now is an LCD panel! This panel is typically rather small for it's resolution - but this doesn't excuse the cost, because LCD production quality is supposed to go up as the size goes down, and the price is supposed to go down as well, right? Well, it hasn't - at least I don't know where I can get a $150.00 800x600 LCD projector yet, which typically uses a smaller LCD display (less than 2" diagonal). Anyhow - all one has to do to build their own LCD projector is to get an LCD about the size of a slide, and drop it in place of the slide in a slide projector (which can be bought cheap off of Ebay). This kind of projector system was first described by Robin Cook in his book "The Virtual Reality Homebrewer's Handbook". One thing he recommended was to use a fan to cool the LCD, because the projection lamp could overheat the LCD, causing it to shut down or burn out. What is used for the LCD? Why, an LCD TV, of course - you take one apart, remove the backlight (because the projection bulb will be your backlight), and put the screen in place of the slide in an old slide projector. You also need to re-route the electronics and cabling, but it can be done. Also, try to use a TV with a TFT display for clearest moving images. It is also possible to scale this up by using larger LCD displays (various electronics surplus dealers sell $99.00 4 inch LCD displays for use in in-car video systems), and a custom lens/projection system. A larger LCD will give a clearer image.
Now, what will be the quality of such a system? All I can compare it to is a device I have, that works the same way, and is how I got my "Big Screen" experience cheap. I own a Fujix P401 LCD projector - cost me $250.00 a few years ago, and gives me an "OK" picture. I can comfortably display X on it if I use a 640x480 setting - some things are readable - but mostly I watch VCDs on it (using mtvp - anyone know of an equal Free replacement to mtvp?). Higher res images can be displayed, but they are fuzzy, at best. I would imagine a homebrew system to be comparable to this, possibly better.
Now, would it be possible to reproduce a three tube CRT system? Of course! You could build three of the 100" systems, but use black and white sets with colored pieces of plexiglas (or stage gels) in front of them. It would be a little bulky, though. I could imagine gutting some small (9" or smaller) portables to do this, and building a custom cabinet. Another possibility is to get (through various electronics surplus retailers on the net) surplus big-screen optics (which shouldn't cost more than $25.00/ea), and put them in front of the CRTs you are using. This would result in a more compact system (especially if you removed the casing of the TVs - be careful of the high-voltage inside, though - one hand in pocket when poking around inside those sets!!!).
Now, what to use for the projection screen - well, since you are doing this on the cheap, you can't very well buy a nice screen - they can be expensive. However, sometimes you can get a used silver projection screen fairly cheap (under $50.00 sometimes on Ebay, less at garage sales) - but make sure it is good quality. Most of these are tripod style, and don't have a ratchet mechanism to allow a "pull-down-from-ceiling" setup, that is much more enjoyable. To solve this, use what I used: A pure-white blackout shade. These can be found at Home Depot, and they can be had for ultra-cheap prices (less than $30.00 for the largest size). You can build mounts by using some bolts and a couple of bookshelf brackets, with careful setup, a pull down system is easy (I had mine together in an hour). These shades are smooth, have a high reflectivity, and are very inexpensive. Another alternative is high reflectivity white paint on a board. You can also use a white vinyl shower curtain, stretched tight. There are numerous options. Just look around and imagine.
Finally, I want to tell you what I used to display X under Linux on a TV (or projection system with composite input, like these homebrew projectors use). There is a device called the Averkey iMicro that is a true plug-and-play system. Pop it into your VGA port, load up X, and it will recognize the settings - no need to mess around with your XF86config settings (unless you need a certain res) - high-res, low-res - don't matter - it can recognise it. And it gives a great image, and it is cheap (around $100). I highly recommend this product.
OK - now you know the scoop. I hope this long, long comment will help someone. Realize that you won't get the be-all and end-all of projection images with these systems. However, I don't think they are a scam - in reality, they are selling the lens and some plans, and true, as good or better plans could be found on-line. But people are lazy, so I tend to think that they are selling a lens, some plans, and the cost of research - for $10.00 or less in many cases, that isn't a bad deal. I tend to wonder if I compiled all the info I had onto a CD, and sold that with a lens, if I could make some cash - but I am lazy, so if someone else wants to take a stab at it, go for it!!!
Have fun, my friends!
Dig up an old 486 or old P90, drop in a couple of NICs and set up FreeSCO...
Easy, painless, secure, and best of all...Free (as in speech and beer).
While I find it hard to imagine someone actually doing this, the idea of building a fishtank-style clean-room and actually using it for this sort of operation does appeal to me.
I can imagine doing it completely off-the-shelf, by building a working envelope with plexiglas and silicone sealant, hooking up two over-large dish gloves (or surgical gloves) with extended cuffs for mobility, and a HEPA filtration system providing a positive pressure feed. Most of the components could be purchased at Walmart.
Actually using it would be interesting for crazy operations like you outline - last resort efforts of the Nth kind. Makes me wonder if any person or group has actually done such a thing...
OK, here is an idea on how to "build" electric boots. I am giving it away free, to the public domain. Hell, it might already be patented, I don't know...
Build a boot with a fairly rigid upper, or with a frame around the upper, in such a manner that there is a semi-flexible pivot and a fully flexible pivot around the ankle (in other words, make it flexible in the full range of motion of the ankle, but try to keep it mostly flexible in the "normal" direction of motion, in line with the rest of the leg.
Around this pivot you would need a gear system, with maybe a ratchet and small flywheel system (like the baycomm radio), so that as the ankle flexes, the flywheel is spun at a high rate of speed. Perhaps even make it spring loaded, so that when standing still, or during mid-stride, the flywheel continues to run for a short while.
Attach a small generator (one of those cheesy 3V motors would be perfect if made a bit more robust), and tap the power.
Feasible? Sounds reasonable to me, though perhaps a little bulky - but I bet with good design, it could be slimmed down and made to work rather well...
Finally, Handspring has done it before everyone else
A coworker of mine currently has (and has had for over a month) a combo cell-phone and Palm III PDA after he got tired of his separate cell-phone and Palm V.
He said he got it from AT&T, I believe - I don't know if it has the whole POP3 email thing, but it is a combo unit.
The Palm forms part of the screen, and the microphone flips down revealing the full thing, and I think a keypad underneath for dialing. It actually isn't a bad integration, though it is a little wide.
I checked on AT&T's website for it though, no dice - maybe it is discontinued?
I sent the following email to one of my senators, John Kyl:
Dear John,
Thank you for passing today an act (USA Act) that helps destroy our fourth amendment - an amendment to the very Constitution you swore to uphold when you took office.
Why must the rights of American citizens be violated for our so-called "safety"?
I am not a senator, something which I would like to think takes great logic and analytical skills, as well as strong morals. But this does not seem to be the case, as you apparently do not understand that SAFETY IS AN ILLUSION. Laws exist to help keep that illusion in place, but once
again, laws themselves are illusions.
The government can not protect me. I do not harbor such illusions. I, myself only, am the only one capable of providing for MY protection.
As a constituent, I look forward to your running for office again.
So I CAN VOTE YOU OUT.
Sincerely,
I sent it using the address "info@kyl.senate.gov", which I found in the FORM code in the page source at http://www.senate.gov/~kyl/con_form.htm
I sent it via normal email, because I also cc'ed the email to our other John, John McCain, so I didn't use the form.
Fat lot of good it would have done me anyway, because here is the form response I got back:
Thank you for writing to me at info@kyl.senate.gov. In an effort to respond as quickly and thoroughly as possible, I am no longer receiving e-mail at this address. I have chosen instead to use a new web-based system that allows me to quickly review the thousands of e-mails I receive and give priority to those from my constituents in Arizona.
There is more, but it is long - suffice to say that the reply went on to note that I should go to the site and the reply form that I had went to originally to get the address!
This is utter bull! I used the address used in the form, and it is an invalid address! So even if I used the reply form, it wouldn't go to him! Am I right on this, or wrong? This is the way it seems. I suppose the CGI could email it elsewhere, but why is the mailto var set to that email address?
ARGH!!!!
True - but as others have pointed out, these dates have the ability to be renewed. Other posters have pointed out that Britain has had "temporary" anti-terrorism laws on the books for over 20 years, simply because the "sunshine clause" keeps getting moved further back.
What is the point of "sunshine clauses" if the sun never rises?
The sphere is connected to the driveshaft. The sphere therefore rotates. If the wobbly plate was attached to the sphere, it would have to rotate as well. However, the metal vane is stationary (held in place by a slot in the two cones), and the wobbly plate is flat against that vane, so it can't rotate, and would therefore not be attached to the sphere.
This is what the animations seem to show.
The only other possible explanation would be that the shaft passes through the sphere, and is connected to the conical ends only, and the the sphere is "free-floating" to an extent, and that the wobbly plate and the vane rotate around everything. However, the animations do not show this, but instead shows the cones (which hold the glow plugs, etc) and the vane to be stationary.
I hope that clears up my explanation. Please remember, though, that I could be wrong in all or part of it. I am merely basing my explanation on a couple of gif animations and a few explanations from the article and website...
Many posters are stating that they either don't hear from their representatives, or they get back form letters - which basically is an acknowledgment of them receiving your letter, but not whether it was read or cared about.
Very few posters have stated they have gotten real non-form letters back. I know on occasion I have gotten ones back, but it has been a rare occasion.
If our representatives are not listening, then do we truely have representation? We are still being taxed, I see that every day. But we seem to have no representation.
I seem to recall something from my history books about a war being fought a while back over "taxation without representation" - or maybe I am mistaken...
That's got to be it - I must be mistaken...
Yeah...
*sob*
What happens if the email is a "praise" email?
Example:
I sent an email yesterday to Feingold in WI. I live in Arizona. The email I sent him was a "good job" type email, and wishing he worked here, and thanking him for his work on behalf of American citizens everywhere.
I included my address, though I doubt I will get any response back (not that I am looking for one).
By your statements, my email got tossed - even though it wasn't a complaint!
Why are our representatives so backward about this stuff. This isn't the future we are talking about, this is the present! It would be like ignoring telephones or faxes (which they apparently still do on the latter).
If they have expirations, they better be hard and fast expirations, and not something along the lines of "When the war is over" or similar.
Note: we are not officially at War! Congress has not declared War!
BTW, if they word it to expire when "the terrorist threat is mitigated" (or some other similar wording) - how do you decide that? Terrorism is not something that will "magically" go away. It has been with human society since the first stick or rock was brandished as a weapon!!! Such wording will do nothing as a "sunshine clause"!
We are not at War, War has not been declared.
/. giving a flying fuck? Hell, the various news sources are reporting it, yet none of them are discussing it - I would be up in arms, so to speak, if I had to report this on camera and in the paper or on the net.
This "war" is as much a "war" as the "war" on (some) drugs is a "war".
Congress has yet to declare War. I do not consider the United States at War until Congress declares war. The President does not, and has never, had this power - only Congress has this power. As of yet they have not exercised it. Yet they are rapidly declaring that the Constitution needs to be shredded (which you understand is happening). Such radical changes to the Constitution means something is falling apart - something is happening - and it must be real, capital "W" - WAR!
Why hasn't Congress declared War? Could it be that such acts as the USA Act would require a sunshine clause should War be declared - that is, that such acts would have to be rolled back once the War was over? Could it be that this so-called "war" can't be really won, and thus it can't be legitimately called a War? Thus, a sunshine clause would not help, since there would be no end? Or that if it can't be won, then a declaration of War would be a declaration of a perpetual War? Could it be that if we declare War, then the USA would be bound by various conventions (Geneva, etc) regarding War and POWs, etc?
WTF is going on - this is crazy - why isn't anyone outside of
I fear the day is dark, and getting darker by the minute. True, the sun still shines, but it means nothing if these shackles are being secured to my body...
I agree - there should be video out, if for nothing more than to bring up the playlist, etc on your TV (which will probably be near your stereo), as well as to add some visualization eye candy for the next party you throw...
I have read a lot of posts here regarding this engine, and I am not absolutely certain that everybody understands how this engine is supposed to work. To be honest, I am not completely certain on how it works, but from looking at the animations and descriptions, I want to attempt to explain it, in the interest of furthering discussion.
I have to admit, the fascinating thing is the fact that it is so simple - so simple that it looks like it could almost be homebrewed in a garage, provided the builder has sufficient machining skills and tools (ie, a metal lathe and mill would be an absolute necessity, as well as a wire-feed welder, among other tools).
Anyway, here is my explanation:
1. The engine is composed primarily of 6 parts: A shaft (1) which is fitted through a sphere (2) and two opposing, on either sides of the sphere, conical ends (3,4), a metal vane (5) which is slotted between the cones, and thus doesn't move - parallel to the shaft/sphere assembly, and perpendicular to the metal vane. Finally, there is the wobbly plate (6), which is fitted around the sphere, and has flattened ends that are up against the metal vane. This plate bisects the sphere, forming two independent combustion chambers. However, it is not attached to the sphere, it does not rotate, and it is not attached to the vane. It merely "slides" against these parts.
2. Now, imagine the metal vane lying at an angle. At the point where one end is touching the cone, and the vane, there is a fuel inlet and a glow plug. Fuel is admitted, and the glow-plug ignites the fuel.
3. As the fuel combusts, it expands, pushing against the plate and the vane, as it races around the chamber, which looks like a expanding wrapped wedge around the sphere. This expansion causes the plate the nutate (wobble) - but not rotate - around ("around" is not a good word, as it implies that the plate is rotating - I must stress that it does not rotate) the sphere. This opens up the chamber, and as the plate slides around the sphere (*), it rotates the sphere 180 degrees, which is connected to the shaft, which turns the shaft 180 degrees.
4. Once the combustion is started, of course the fuel inlet is closed. When the combustion is completed, the plate is now lying at the opposite angle. An exhaust port is opened (I would imagine the opening and closing of exhaust and inlet ports to be accomplished by solenoid valves of some sort), and the inlet port on the other side is opened to cause the other side to fire, to rotate the shaft 180 degrees more, while simultaneously pushing the exhaust out (by action of the plate) on the opposite side.
5. The cycle repeats.
(*) - Notice how many parts are sliding against each other? I can't understand how this thing is supposed to run dry - ie, no lubricant - unless the fuel is to provide the lubrication of some sort. All that friction will get it damn hot if it isn't lubricated and cooled in some manner.
Furthermore, I am not certain how the plate, rubbing up and acting on the sphere (nutating "around") spins the sphere, unless is it by some strange vector motions being imparted by friction.
The interesting thing about this, though - is if that is the case, if the motor shaft is somehow stalled for whatever reason, the engine shouldn't die - it should only become hotter than normal, which may or may not be a good feature.
---
I hope this explanation helps - I hope it is right, I am pretty certain it is. Please discuss below, and comment on it - I would be pleased to know what others think...
It uses a steel belt, composed of what appears to be a lot of parts (supposedly high-strength parts). In a go-cart, similar systems are used, but use a funky shaped "v" belt (it isn't a true V shape).
I do have to say if that belt did break, it would probably be a mess...
Forget what I posted - I found the site.
The wobbly plate does not spin - there is a stationary vane on one side fitted into slots on the cones. The plate appears to wobble because it is fired on one side of where the plate and the cone and the stationary vane come together. As the explosion expands and progresses, it causes the plate to move and wobble. I am not sure how this gets the sphere spinning, though, unless just by frictional contact and through various motion vectors the sphere moves.
I would still think all of this would need severe lubrication and tight tolerances...
Are you speaking of the McMaster engine, or the quasi-turbine (they are two separate designs)? If it is the former, please provide a link - if it is the latter, then I am wondering this too, but I have to investigate further...
BTW - wasn't the Wankle engine's combustion chamber cardoid shaped, not peanut shaped?
Explanation for those who don't speak patent-ese:
Take a piece of plywood. Cut a hole, mount a speaker on the front. Now, build a plastic/rubber bladder/balloon to attach to the sides, so that your now have a "box shape" - optionally with side "arms" to hold the edges forming the sides ridged. Add a valve and pump it up.
In other words, the bladder forms the structure to hold the speaker up, and the plywood panel serves to have a place to mount the speaker.
Bet I know what it sounds like, too - CRAP! This is basically a "boxless" or "baffless" design - where the panel is just a speaker mounting point, not much else (keeps a little sound from radiating forward). Grab a speaker design book from the 50s, early 60s, and you will see this design. Even then it sucked, just not as bad because speakers in general weren't that great.
These "blow-up" speakers might be OK if the bladder is of a sufficiently thick material, and it is kept at a high pressure level, but they won't be "great"...
I might have to check it out again, then.
I stopped playing with it a couple of years back. The things I keep waiting for is:
Trees
Sunlight thru clouds
One other thing I would love to see (any possibility of?) is a Linux/X port. Basically, since you have the C++ stuff taken care of, most of it would be a UI interface, right (using GTK or some similar lib for that would work)?
Very true...
Good point, AC - got any ideas on getting around this?
I am thinking fiber link of some type - not sure if that would be the best answer, though...
If you want to be REAL paranoid...
.25 inch steel plate. Add ventilation holes. Put the computer inside, maybe with a UPS as well. Run cables out of it via romex sheathing to power and monitor, and weld the romex to the box. DO NOT hook up any printer or modem - or if you do, place it in the box with the computer.
Build a large steel cabinet, using
Create a wireless IR keyboard interface, with one of those mini keyboards - plus possibly custom software drivers and/or hardware interfaces for it. Provide a hole so that the IR x/r unit can "see" out of the box to the keyboard.
Lock the box up in some manner - tack welding might be preferable. Add a power switch to the outside of the box, maybe a few status LEDs.
Take the keyboard with you whenever you are not with the machine. Perhaps sleep with it under your pillow, or put it in a safe under your bed or something. Follow the rule about using epoxy on the screws. Maybe put seals over the welds, or take pictures of the welds to compare with every now and then (say once a week). You might even want to place the monitor in a copper wire mesh bag or Faraday cage, propely sealed and grounded for stray RF emmisions. Maybe not even provide a modem, only a floppy drive of some sort - and do all decryption of that secured machine. Won't stop "them" from tracking who/when you comm with other parties (ie, traffic analysis), but will keep them from logging you.
If you are truely needing this, you will see that what I suggest is actually worthwhile...
Generating a simple fractal landscape is both an easy and a difficult process. The algorithm is relatively easy - it is the implementation that can be difficult.
It is possible to implement a fractal landscape generation system on using only 2D graphics, which produce an image that looks amazingly 3D in scope, but isn't. Of course, it is possible to do the same algorithm in a 3D coordinate system.
I came across the 2D method first in an old Creative Computing article from around 1983 (the issue was the "graphics" issue, and in addition to the fractal mountain code done in BASIC for a couple of systems, there was an article that detailed making photo masks and combining computer graphics and real photo techniques to produce cool effects for the time - today, photoshop works wonders). The BASIC code was for a PCjr (IIRC) and an Apple IIe, but I converted it to my TRS-80 Color Computer - and it ran fine (though very slowly).
Essentially, the process is:
1. Select three random (X,Y) points on the screen - these form the "base" triangle.
2. Find the midpoints of each side of the base triangle. Split each side in half (subdivide it), and move the midpoint up/down by a small random amount (in the Y direction on screen), and join the points - the deformed triangle should now be composed of 4 sub-triangles.
3. Repeat the process on each of the resulting sub-triangles n-times.
Of course, n tends to be a small number - around 7-10, depending on the resolution of your output device. There is also a way to add "water" by deciding on an certain "Y" level to disallow drawing of "land", instead showing "water" (where "land" is green, brown, or grey, and "water" is blue).
That's the basic algorithm, and the hard part is keeping all the sub-triangle's vertices joined, so that when one is shifted up, the adjoining triangle's vertex shifts up as well. In the Creative Computing article, this was accomplished with arrays and really complex code that wasn't explained too well. Today, you would probably use a combination of linked-lists of objects (where each object represents a vertex), and of course a recursive function system. It would end up being more of a memory hog, but it would be easier to code as well.
Taking the algorithm into the 3rd dimension would be easy, since you would plot the base triangle on the X/Z (or X/Y) plane, then as you went through the subdivision process, you would simply change the height of each vertex in the Y (or Z) plane respectively.
I have to agree with you AC, that Terragen is very impressive.
Want to know what is more impressive about it?
It is written mostly in Visual Basic (don't believe me? Email the author. I found out after having a conversation with him about using VB for 3D stuff like this a few years ago, because I noticed it installing the VB runtime during setup).