Looks like ex-president Nixon. Good result for a single 2 cents led.
There's no reason you shouldn't use the PC PSU 12V line, with a series parallel configuration. Dimension R so that you have the rated current though (12-3*3.4)/.02=90ohm. Since your leds seem to work at 5x the rated current, even if 2 leds would go short circuit the remaining one would still be safe.
Of course, as every LCD, the ones used in projectors need polarised light to achieve contrast. I just read that newest polarizer films used a tricky design to achieve 1.5x better flux than older ones. They indeed recycle perpendicular light, otherwise lost.
Next step make an array of leds, and beam each to a common circle at the final LCD distance. I have a crazy trick which might help at that stage.
Ozone, have you tried switching the leds without complicating with PICs? All you need is to supply them in sync with the mirrors.
I believe leds working at say 1/3 duty cycle with 3x rated current maintain their lumen flux. So sequential DLP is no longer handicapped. Looks like commercial units already emerged. Samsung also sells a 700Eur 25lm portable led DLP projector, but it's only SVGA. It may be worth investing in a DLP vs 3LCD.
There's no reason you shouldn't use the PC PSU 12V line, with a series parallel configuration. Dimension R so that you have the rated current though (12-3*3.4)/.02=90ohm. Since your leds seem to work at 5x the rated current, even if 2 leds would go short circuit the remaining one would still be safe.
Of course, as every LCD, the ones used in projectors need polarised light to achieve contrast. I just read that newest polarizer films used a tricky design to achieve 1.5x better flux than older ones. They indeed recycle perpendicular light, otherwise lost.
Next step make an array of leds, and beam each to a common circle at the final LCD distance. I have a crazy trick which might help at that stage.
Ozone, have you tried switching the leds without complicating with PICs? All you need is to supply them in sync with the mirrors.
I believe leds working at say 1/3 duty cycle with 3x rated current maintain their lumen flux. So sequential DLP is no longer handicapped. Looks like commercial units already emerged. Samsung also sells a 700Eur 25lm portable led DLP projector, but it's only SVGA. It may be worth investing in a DLP vs 3LCD.
Hi zzonbi,
I'm still a bit confused as to which configuration on LEDs you could use that would protect them if one or more of them decided to short-circuit?
If all the LEDs in a row are in parallel, and one of them shorts out, the whole row would of course be shorted too, and the resistor then takes the load, but.....
If they're in series and some of them short out, the rest of the LEDs in the row receive too much voltage and could be damaged? What's the recommeded method of connection?
With the DLP sequencer board, the idea was to remove the colour wheel altogether. The problem is that the speed variable sent to the motor drive chip over a data bus is what drives the whole sync process.....
There's no simple sync pulse that shows how fast the wheel is needs to rotate, and the PJ also uses the speed control to keep the colour wheel in sync with the incoming frame rate.
You could leave the motor in place (out of the light path), and clock the colour changes from it with extra opto-reflectors, but I'd rather have an elegant solution to the problem, and you'd still need some sort of logic for the switching even then, so you might as well use a PIC chip.
(Well, you could use a simple counter chip, but the goal was also to remove the noise of the colour wheel.)
I think the design would work as it is now with two PIC chips. In fact, it's only the capture of the speed data which I can't test until I build something. The data rate looks pretty fast, but is only 24 bits. (I don't have an oscilloscope to check the actual data rate.)
The first chip (which I call the ClockGen) receives the speed variable from the data bus between the PJ and the motor drive chip, it then generates the clock pulses which drives the rotation of the "virtual colour wheel" (or CSB - Colour Sequencer Board) which is made using the second PIC chip.
This method of using two chips looks like the only simple way of getting accurate timing out of the thing. With only one chip, the aquisition of the speed data caused the timing of the "virtual colour wheel" to play up.
The good thing is, with the CSB, you can progam it to any number of segments on your original colour wheel, and add combinations (like creating a white segment etc.) The top speed is still around 166Hz with the 20MHz PIC chips I'm currently using.
An FPGA would be ideal for this type of thing, but I only have limited programming knowledge of those things.
However, I think my PWM board design works very well (simulated), and can have many outputs. I don't think anyone would need more than 6 outputs though.
I'm still a bit confused as to which configuration on LEDs you could use that would protect them if one or more of them decided to short-circuit?
If all the LEDs in a row are in parallel, and one of them shorts out, the whole row would of course be shorted too, and the resistor then takes the load, but.....
If they're in series and some of them short out, the rest of the LEDs in the row receive too much voltage and could be damaged? What's the recommeded method of connection?
With the DLP sequencer board, the idea was to remove the colour wheel altogether. The problem is that the speed variable sent to the motor drive chip over a data bus is what drives the whole sync process.....
There's no simple sync pulse that shows how fast the wheel is needs to rotate, and the PJ also uses the speed control to keep the colour wheel in sync with the incoming frame rate.
You could leave the motor in place (out of the light path), and clock the colour changes from it with extra opto-reflectors, but I'd rather have an elegant solution to the problem, and you'd still need some sort of logic for the switching even then, so you might as well use a PIC chip.
(Well, you could use a simple counter chip, but the goal was also to remove the noise of the colour wheel.)
I think the design would work as it is now with two PIC chips. In fact, it's only the capture of the speed data which I can't test until I build something. The data rate looks pretty fast, but is only 24 bits. (I don't have an oscilloscope to check the actual data rate.)
The first chip (which I call the ClockGen) receives the speed variable from the data bus between the PJ and the motor drive chip, it then generates the clock pulses which drives the rotation of the "virtual colour wheel" (or CSB - Colour Sequencer Board) which is made using the second PIC chip.
This method of using two chips looks like the only simple way of getting accurate timing out of the thing. With only one chip, the aquisition of the speed data caused the timing of the "virtual colour wheel" to play up.
The good thing is, with the CSB, you can progam it to any number of segments on your original colour wheel, and add combinations (like creating a white segment etc.) The top speed is still around 166Hz with the 20MHz PIC chips I'm currently using.
An FPGA would be ideal for this type of thing, but I only have limited programming knowledge of those things.
However, I think my PWM board design works very well (simulated), and can have many outputs. I don't think anyone would need more than 6 outputs though.
"One advantage with using lots of LED's is that by wiring them all in series, you can use a higher voltage power supply. The downside of this is that if one LED blows (open circuit), the whole thing will go dark. But if they're all good to begin with and you protect it from overvoltage and surge (a cap and zener diode across the assembly?), it should last a long long long time!"
this is advice from Techfan at projector central
don't know what it means, but it may be the solution to blowing entire arrays
this is advice from Techfan at projector central
don't know what it means, but it may be the solution to blowing entire arrays
I see, so the wheel is actually sync-ed to the vertical refresh rate of the VGA input. If the loop is indeed feed-forward, perhaps the motor locks its phase in the manner of a PLL circuit.
Maybe you can use the vertical sync signal of the VGA line directly. The delays could be trimmed with simpler RC circuits.
I totally agree an elegant solution would do without the mechanical wheel at all (a colour square?).
No led comes directly in parallel to another. They use resistors in between. The resistors and the remaining leds can deal with the increased current (throwit drives them 5x already).
So we have the series element R-L-L-L, and these elements come in parallel, all connected to 12V. Even with 3 leds shorted R is dimensioned to not burn 12*12/90=1.6W
throwit, I was thinking, if you can't get uniform light across the screen from your built led array, perhaps you should spin them, on a PC fan for example. You might get some cooling too, as a colateral bonus.
Maybe you can use the vertical sync signal of the VGA line directly. The delays could be trimmed with simpler RC circuits.
I totally agree an elegant solution would do without the mechanical wheel at all (a colour square?).
No led comes directly in parallel to another. They use resistors in between. The resistors and the remaining leds can deal with the increased current (throwit drives them 5x already).
So we have the series element R-L-L-L, and these elements come in parallel, all connected to 12V. Even with 3 leds shorted R is dimensioned to not burn 12*12/90=1.6W
throwit, I was thinking, if you can't get uniform light across the screen from your built led array, perhaps you should spin them, on a PC fan for example. You might get some cooling too, as a colateral bonus.
It could be called a PLL method in a way, as this is how the motor drive chip compares the speed of the motor to the programmed speed.
The problem with using the input refresh rate or vertical sync would be how the DLP chipset delays these frames. Not to mention the fact that there's generally more than one input to content with.
It might be possibly to take the sync output from the video decoder chip. In the case of this Proxima, the video decoder handles the TV format inputs (composite and s-video). I can't be sure it handles the VGA input too though.
And this is where the main purpose of the CSB comes into play: The idea being to make it as generic as possible, so everyone with a DLP projector who wants to fit LED lamps could benefit without too much hassle.
Using simple RC circuit or logic might be possible, but then you have the problem that the delays change as the "wheel" spins faster or slower.
Yet another factor is the motor drive chip needs the feedback pulse via the opto-reflector to tell when the wheel is spinning at the correct speed, as well as if it's in phase with the sync or not.
Zener diodes would be a good idea. I don't know how you would arrange them? If you put one across your voltage source (after the resistors) to limit the voltage, you'd need a different Zener voltage rating for everyone's input voltage? (does that make sense!?)
I thought that if too many LEDs short-circuit in a series, the rest of the LEDs would receive too much voltage? Regardless of how much extra power the resistor dissipates? I'm not sure on this stuff, so please don't flame me!
The problem with using the input refresh rate or vertical sync would be how the DLP chipset delays these frames. Not to mention the fact that there's generally more than one input to content with.
It might be possibly to take the sync output from the video decoder chip. In the case of this Proxima, the video decoder handles the TV format inputs (composite and s-video). I can't be sure it handles the VGA input too though.
And this is where the main purpose of the CSB comes into play: The idea being to make it as generic as possible, so everyone with a DLP projector who wants to fit LED lamps could benefit without too much hassle.
Using simple RC circuit or logic might be possible, but then you have the problem that the delays change as the "wheel" spins faster or slower.
Yet another factor is the motor drive chip needs the feedback pulse via the opto-reflector to tell when the wheel is spinning at the correct speed, as well as if it's in phase with the sync or not.
Zener diodes would be a good idea. I don't know how you would arrange them? If you put one across your voltage source (after the resistors) to limit the voltage, you'd need a different Zener voltage rating for everyone's input voltage? (does that make sense!?)
I thought that if too many LEDs short-circuit in a series, the rest of the LEDs would receive too much voltage? Regardless of how much extra power the resistor dissipates? I'm not sure on this stuff, so please don't flame me!
nice idea with spinning the leds zzonbi, and it would surely work (though you may be overestimating my skills !)...i was genuinely shocked by how much integrity the displayed image had - i was really not expecting the light to be so balanced (with the corners fully lit), as it turned out to be
most likely a result of the distance between the led and the lcds, probably a total distance of around 200mm to 300mm (taking circuitous route into consideration)
most likely a result of the distance between the led and the lcds, probably a total distance of around 200mm to 300mm (taking circuitous route into consideration)
200-300mm? With a 26 degree angle you lose a lot of light sideways. C'mon, try an R, G and B led closer to each panel, with no mirrors, and post a pic.
But for a given refresh rate the wheel speed is not supposed to change. Without synching the wheel phase would shift in time, but the leds would be forever synched, better said switched, each period, precisely at the right moment. There is no drift now.
Can't you test if the wheel is required at all for the DLP chip to work?
With the leds the problem is more limiting their current. The greater the R the better you stabilise it, but at the cost of higher Joule losses. I assume the supply voltage is already stabilised, so why use Zener diodes? BTW, phone cell chargers are sometimes constant current generators. Those can be used with no resistors at all.
But for a given refresh rate the wheel speed is not supposed to change. Without synching the wheel phase would shift in time, but the leds would be forever synched, better said switched, each period, precisely at the right moment. There is no drift now.
Can't you test if the wheel is required at all for the DLP chip to work?
With the leds the problem is more limiting their current. The greater the R the better you stabilise it, but at the cost of higher Joule losses. I assume the supply voltage is already stabilised, so why use Zener diodes? BTW, phone cell chargers are sometimes constant current generators. Those can be used with no resistors at all.
I tried the Proxima without the colour wheel plugged in before, but no image appears (with the wheel stuck on red) as the DLP engine requries the timing pulses from the opto-reflector before it will display anything. (The rotation of the colour wheel "drives" the sequencing of the RGB frames.)
You would need to fake the opto-reflector signal on the original colour wheel to get the DLP to display the frames.
Also, the colour wheel does actually change speed on the Proxima DS1 in relation to the incoming vertical sync. This also happened on my InFocus X1, so it's not just a 1st generation DLP attribute.
The delays between the switching of the colours will of course get shorter as the wheel (virtual, or real) spins faster.
The strange quirk of the Proxima is that it doesn't shut down if the wheel motor isn't plugged in. Most DLP projectors will most certainly shut down in this case.
The use of zener diodes would be for across the array. This should protect the other diodes in a series array from when the voltage goes too high if some of the other LEDs in the row were to short-circuit? The power source would be assumed to be properly regulated I hope! 😉
You would need to fake the opto-reflector signal on the original colour wheel to get the DLP to display the frames.
Also, the colour wheel does actually change speed on the Proxima DS1 in relation to the incoming vertical sync. This also happened on my InFocus X1, so it's not just a 1st generation DLP attribute.
The delays between the switching of the colours will of course get shorter as the wheel (virtual, or real) spins faster.
The strange quirk of the Proxima is that it doesn't shut down if the wheel motor isn't plugged in. Most DLP projectors will most certainly shut down in this case.
The use of zener diodes would be for across the array. This should protect the other diodes in a series array from when the voltage goes too high if some of the other LEDs in the row were to short-circuit? The power source would be assumed to be properly regulated I hope! 😉
Hmm, so the frame rate doesn't need to be a multiple of the wheel speed, and not even synched. Maybe then the DLP is piloted by the spoke events instead. I'll leave it here, since I only have suppositions.
A Zener in series would only cut off a slice of the supply voltage, just like using a lower voltage supply, but the real issue is limiting led current. A resistor is much better, a Zener is not needed at all IMO. That's because I varies greatly with V for a given led, and varies from one led to another, even if of the same type, for the same V. Possibly varies also with changing operating conditions, as temperature, wear??
A Zener in series would only cut off a slice of the supply voltage, just like using a lower voltage supply, but the real issue is limiting led current. A resistor is much better, a Zener is not needed at all IMO. That's because I varies greatly with V for a given led, and varies from one led to another, even if of the same type, for the same V. Possibly varies also with changing operating conditions, as temperature, wear??
Hi,
Yes, the frame rate is the same as the wheel speed on my Proxima. The wheel speeds up to match the incoming vertical sync.....
ie. PAL video input = 50hz, colour wheel = 50RPS (revolutions per second)
VGA input = 75hz, colour wheel = 75RPS etc,
This must be a 1X speed wheel PJ then (1st generation). The colour wheel only has one point where the opto-reflector is pulsed (has a silver sticker on the wheel) so the DLP engine only receives one pulse per revolution.
zzonbi, your suggestions are always welcome! Anything is helpful, as I still need ideas to have a chance of getting this thing working.
Yes, the frame rate is the same as the wheel speed on my Proxima. The wheel speeds up to match the incoming vertical sync.....
ie. PAL video input = 50hz, colour wheel = 50RPS (revolutions per second)
VGA input = 75hz, colour wheel = 75RPS etc,
This must be a 1X speed wheel PJ then (1st generation). The colour wheel only has one point where the opto-reflector is pulsed (has a silver sticker on the wheel) so the DLP engine only receives one pulse per revolution.
zzonbi, your suggestions are always welcome! Anything is helpful, as I still need ideas to have a chance of getting this thing working.
"C'mon, try an R, G and B led closer to each panel, with no mirrors, and post a pic"
lol give me a chance !
i understand that the leds i used are less than 15 degree angle, plus there are lenses and other means to ensure a tight beam, something i will no doubt make use of as the leds draw nearer
i have ideas and too little money, if i had the money i'd most certainly have done that by now
lol give me a chance !
i understand that the leds i used are less than 15 degree angle, plus there are lenses and other means to ensure a tight beam, something i will no doubt make use of as the leds draw nearer
i have ideas and too little money, if i had the money i'd most certainly have done that by now
Oops, guess I missread this phrase: "Also, the colour wheel does actually change speed on the Proxima DS1 in relation to the incoming vertical sync". So the wheel is locked to the vertical frame rate after all. Good luck with the PIC programming then, it seems indeed more flexible when dealing with unequal colour sectors/different frame rates than simpler circuitry.
The specs page on e-bay mentioned a 13 degree half angle. It's easy to measure the actual value though.
One thing though, if I was to buy more 50 led packs at once, would the shipping remain the same as for one pack? If yes, I'd rather buy 1000leds for 36.8$ instead of 50leds for 17.99$.
http://cgi.ebay.co.uk/NEW-50X-10MM-...2118717QQihZ016QQcategoryZ66952QQcmdZViewItem
There are also these leds:
http://cgi.ebay.com/4CHIP-POWER-LED...620985444QQcategoryZ66952QQrdZ1QQcmdZViewItem
higher flux but looser beam and lower lm/W. If they use the "4 chip" technology and not phosphor for obtaining white, they're okay for projection.
The specs page on e-bay mentioned a 13 degree half angle. It's easy to measure the actual value though.
One thing though, if I was to buy more 50 led packs at once, would the shipping remain the same as for one pack? If yes, I'd rather buy 1000leds for 36.8$ instead of 50leds for 17.99$.
http://cgi.ebay.co.uk/NEW-50X-10MM-...2118717QQihZ016QQcategoryZ66952QQcmdZViewItem
There are also these leds:
http://cgi.ebay.com/4CHIP-POWER-LED...620985444QQcategoryZ66952QQrdZ1QQcmdZViewItem
higher flux but looser beam and lower lm/W. If they use the "4 chip" technology and not phosphor for obtaining white, they're okay for projection.
no, i think the shipping remains pretty well the same for both types...$1 off for each extra set ! 😀
Hi,
I discovered last night that me saying the colour wheel speed is the same as the incoming vertical sync is inaccurate.....
I hooked up the vertical sync output of the video decoder chip, plus the optoreflector pulse output to my PC's sound card (cheapo o'scope), and on a 50Hz PAL video input, the colour wheel speed was actually 66.6666Hz!! (1.3:1)
The pulses were actually in sync as they followed a repeating pattern every four pulses. This means that there's probably a minimum wheel speed, and the projector does some clever magic to keep the wheel speed up with lower input frame rates. I haven't tried this with an NTSC input signal or VGA input yet, but I'm guessing the colour wheel would be the same speed as the VGA vertical refresh rate above say 60Hz??
I had heard of this spooky colour wheel behaviour before on reviews of other DLP projectors. So, this looks like yet another good reason to take the speed data from the motor drive chip instead.
Early tests of the ClockGen software on a PIC look promising. The PIC chip I'm using is on it's last legs (excuse the pun), so keeps loosing it's programming data, but it did actually respond to the data input from the colour wheel motor chip and send out some clock pulses.
The clock pulses didn't change with the colour wheel speed as yet, but this is probably because I need to use a 20MHz crystal instead of the 10MHz I had lying around. I'll order some new chips soon and build something properly.
What I really need is a cheap logic analyser for around 10MHz - Any suggestions?
As long as I can get the ClockGen PIC working properly, it looks like the CSB will work very well for switching your RGB LED array after we can figure out the LED lamp stuff.
The PWM board should also work fine for dimming your LED arrays. I think a board with 4 to 6 PWM outputs should be more than adaquate for most people. I'll also get and build one of those in the new few weeks.
I discovered last night that me saying the colour wheel speed is the same as the incoming vertical sync is inaccurate.....
I hooked up the vertical sync output of the video decoder chip, plus the optoreflector pulse output to my PC's sound card (cheapo o'scope), and on a 50Hz PAL video input, the colour wheel speed was actually 66.6666Hz!! (1.3:1)
The pulses were actually in sync as they followed a repeating pattern every four pulses. This means that there's probably a minimum wheel speed, and the projector does some clever magic to keep the wheel speed up with lower input frame rates. I haven't tried this with an NTSC input signal or VGA input yet, but I'm guessing the colour wheel would be the same speed as the VGA vertical refresh rate above say 60Hz??
I had heard of this spooky colour wheel behaviour before on reviews of other DLP projectors. So, this looks like yet another good reason to take the speed data from the motor drive chip instead.
Early tests of the ClockGen software on a PIC look promising. The PIC chip I'm using is on it's last legs (excuse the pun), so keeps loosing it's programming data, but it did actually respond to the data input from the colour wheel motor chip and send out some clock pulses.
The clock pulses didn't change with the colour wheel speed as yet, but this is probably because I need to use a 20MHz crystal instead of the 10MHz I had lying around. I'll order some new chips soon and build something properly.
What I really need is a cheap logic analyser for around 10MHz - Any suggestions?
As long as I can get the ClockGen PIC working properly, it looks like the CSB will work very well for switching your RGB LED array after we can figure out the LED lamp stuff.
The PWM board should also work fine for dimming your LED arrays. I think a board with 4 to 6 PWM outputs should be more than adaquate for most people. I'll also get and build one of those in the new few weeks.
The formula I wrote on post 109 is incorrect, sin b must be erased.
I correct also post 135, as this means the online calculator uses the same corrected formula.
Unfortunately it's unlikely the 4 chip leds have indeed 32lm, or the jumbo 10mm white leds 20lm. The specs are probably pumped up. There is some confusion about the beam angle too.
Yep, they want 300$ for 1000leds, so it looks like the shipping price does not reflect reality.
You can vary the V frequency very finely using a program called powerstrip.
On a second thought I don't see why the V refresh and DLP RGB refresh wouldn't be independant, particularly if the DLP chip can update all its micromirrors very quick.
I correct also post 135, as this means the online calculator uses the same corrected formula.
Unfortunately it's unlikely the 4 chip leds have indeed 32lm, or the jumbo 10mm white leds 20lm. The specs are probably pumped up. There is some confusion about the beam angle too.
Yep, they want 300$ for 1000leds, so it looks like the shipping price does not reflect reality.
You can vary the V frequency very finely using a program called powerstrip.
On a second thought I don't see why the V refresh and DLP RGB refresh wouldn't be independant, particularly if the DLP chip can update all its micromirrors very quick.
okay... i've been following the LED pj scene from lumenlab forums and found those chinese guys' LED board to have acceptable results. i'm now looking into lamina's 3000 series LED arrays (using a 2x2 grid of them for a small lcd projector should yield 2100lm before optics). now i have nowhere near the level of technical understanding that you guys do so i want to ask...
is the $90+ cost of a single lamina array is justified in it's output over using standard "super bright" LEDs self soldered onto a grid of the same size? can i achieve comparable results? sorry for hijacking the thread but it seems to have moved into fitting a commercial projector with LEDs. great step towards a solution but doesn't seem to help me getting a DIY projector done.
is the $90+ cost of a single lamina array is justified in it's output over using standard "super bright" LEDs self soldered onto a grid of the same size? can i achieve comparable results? sorry for hijacking the thread but it seems to have moved into fitting a commercial projector with LEDs. great step towards a solution but doesn't seem to help me getting a DIY projector done.
hi killerofangels
we've all hijacked it !...you're putting it back how it should be
i have a clear conscience about my hijacking to commercial projectors (as you say), because some of the issues and solutions may overlap
broadly speaking i think it is more effective in terms of brightness and cost, to use individual leds built up into an arraY
we've all hijacked it !...you're putting it back how it should be
i have a clear conscience about my hijacking to commercial projectors (as you say), because some of the issues and solutions may overlap
broadly speaking i think it is more effective in terms of brightness and cost, to use individual leds built up into an arraY
Hi,
Does anyone know what the guys and girls at the Chinese forum consider to be the best LEDs at the moment (bang for buck)?
I'm finding the babelfish translation of the Chinese forum very slow. It does have some very amusing translations though. Surely the following sentence can't have the original meaning!?.....
"LED which previous two days attained which the eldest child to have provided 3.0 worns out fur woman with no pubic hair use, own raised a rumpus has made a worn out fur woman with no pubic hair, and changed in the power supply" 😀
Anyway, I've found a few sites which might prove useful for us. Here's the BLTDirect site. They sell Luxeon's and other LED lamps, but they also sell fairly cheap power supplies....
http://www.bltdirect.co.uk/cat564_1.htm
Their colour changer controllers are quite expensive at £50 (including VAT). I'm sure I could easily compete with that, and I could add computer control and PWM dimming!....
http://www.bltdirect.com/product.php?pid=7696&cat=745&nm=
This next site has been around for a while, but what is slightly annoying is that it concentrates on the LED efficiency and it's hard to find the actual light output of many of the examples.....
http://members.misty.com/don/led.html
There are some good links on that site though. The Cree company is a new one to me, and they seem to be making some of the brightest LEDs around atm. (Well, at least some of the most efficient, I'm not sure if that translates to the highest output too?).....
http://www.cree.com/press/press_detail.asp?i=1150834953712
The lighting page of the Sandia institue is also an excellent page for the latest in LED technology.....
http://lighting.sandia.gov/Xlightingnewsheadline.htm
(I must keep in mind that Osram = Siemens and Luxeon = Philips)
Another great site, LEDs Magazine....
http://www.ledsmagazine.com/press/8698
These very high power LED emitters from Edison Opto look fantastic, but I'd hate to think how much they'd cost....
http://www.edison-opto.com.tw/product_lighting_detail4.asp?cno=1
....They only measure from 8.4mm to 14.5mm square, and have up to 700 lumens of light output! That's an incredible amount of power output for that size, and the highest I've seen so far. They even make RGB versions!
The datasheets for the Edison LEDs are great - They show in a simple way how to power their LEDs and which resistor to use. The angle of light output is around 120 degrees apparently?
Another seller of bright LEDs....
http://www.ledsupply.com
These are just a few of the sites I found on the news pages of LED Magazine, and on the LED museum site. I haven't spent much time on these pages yet, but it looks very promising. I was starting to think that the idea of using LEDs in projectors wasn't going to happen any time soon, but it seems they will indeed have LEDs that will be cheap and bright enough in the very near future.
I found this site about replacement lamps too. I should really post it in the lamp thread, but it looks like it might be very useful.....
http://www.lampbank.nl/kk_3900005.html
I've discovered that there are quite a few errors in the "manufacturers replacement datasheet" from the diypro site. For example, it states different wattages for projectors, and sometimes even says AC for one PJ and DC for another when both PJs are suppose you use the same lamp!?
Does anyone know what the guys and girls at the Chinese forum consider to be the best LEDs at the moment (bang for buck)?
I'm finding the babelfish translation of the Chinese forum very slow. It does have some very amusing translations though. Surely the following sentence can't have the original meaning!?.....
"LED which previous two days attained which the eldest child to have provided 3.0 worns out fur woman with no pubic hair use, own raised a rumpus has made a worn out fur woman with no pubic hair, and changed in the power supply" 😀
Anyway, I've found a few sites which might prove useful for us. Here's the BLTDirect site. They sell Luxeon's and other LED lamps, but they also sell fairly cheap power supplies....
http://www.bltdirect.co.uk/cat564_1.htm
Their colour changer controllers are quite expensive at £50 (including VAT). I'm sure I could easily compete with that, and I could add computer control and PWM dimming!....
http://www.bltdirect.com/product.php?pid=7696&cat=745&nm=
This next site has been around for a while, but what is slightly annoying is that it concentrates on the LED efficiency and it's hard to find the actual light output of many of the examples.....
http://members.misty.com/don/led.html
There are some good links on that site though. The Cree company is a new one to me, and they seem to be making some of the brightest LEDs around atm. (Well, at least some of the most efficient, I'm not sure if that translates to the highest output too?).....
http://www.cree.com/press/press_detail.asp?i=1150834953712
The lighting page of the Sandia institue is also an excellent page for the latest in LED technology.....
http://lighting.sandia.gov/Xlightingnewsheadline.htm
(I must keep in mind that Osram = Siemens and Luxeon = Philips)
Another great site, LEDs Magazine....
http://www.ledsmagazine.com/press/8698
These very high power LED emitters from Edison Opto look fantastic, but I'd hate to think how much they'd cost....
http://www.edison-opto.com.tw/product_lighting_detail4.asp?cno=1
....They only measure from 8.4mm to 14.5mm square, and have up to 700 lumens of light output! That's an incredible amount of power output for that size, and the highest I've seen so far. They even make RGB versions!
The datasheets for the Edison LEDs are great - They show in a simple way how to power their LEDs and which resistor to use. The angle of light output is around 120 degrees apparently?
Another seller of bright LEDs....
http://www.ledsupply.com
These are just a few of the sites I found on the news pages of LED Magazine, and on the LED museum site. I haven't spent much time on these pages yet, but it looks very promising. I was starting to think that the idea of using LEDs in projectors wasn't going to happen any time soon, but it seems they will indeed have LEDs that will be cheap and bright enough in the very near future.
I found this site about replacement lamps too. I should really post it in the lamp thread, but it looks like it might be very useful.....
http://www.lampbank.nl/kk_3900005.html
I've discovered that there are quite a few errors in the "manufacturers replacement datasheet" from the diypro site. For example, it states different wattages for projectors, and sometimes even says AC for one PJ and DC for another when both PJs are suppose you use the same lamp!?
Hi everyone,
I received the jumbo (10mm) LEDs today and I tried some of them in the Proxima DLP projector.....
The results were slightly disappointing, but I suppose this is an early test, and I'm not using a lens or anything yet. We also know now that we need at least 600 lumens to achieve anything approaching a watchable image.
I've only tried five of the 10mm LEDs so far (not very many!). They were running at about 70mA, but anything higher than that didn't seem to increase the brightness by a huge amount.
The image was mostly unwatchable on dark scenes in a dark room. In brighter scenes, you could see the bright parts of the image, but not very well. It's nowhere near as good as the 50Watt halogen, but that's to be expected.
So, unless you want to use a large LED array for the bigger LCD panels, or unless we can find a fairly cheap super-high brightness LED module, I don't think you can use these "simple" LED solutions for commercial projectors very easily at all. Of course, people have had success with using huge LED arrays on 7 inch screens though.
Oh well, it's early days for me yet and I'm still looking for other LED candidates for modding commercial projectors with. LED technology is getting better every month, so it won't be long before the prices start coming down and the LED modules get small and bright enough.
The high-power LED modules from Edison Opto look very promising. I just need to e-mail them now to see if they'll give me a price on them. 😉
I received the jumbo (10mm) LEDs today and I tried some of them in the Proxima DLP projector.....
The results were slightly disappointing, but I suppose this is an early test, and I'm not using a lens or anything yet. We also know now that we need at least 600 lumens to achieve anything approaching a watchable image.
I've only tried five of the 10mm LEDs so far (not very many!). They were running at about 70mA, but anything higher than that didn't seem to increase the brightness by a huge amount.
The image was mostly unwatchable on dark scenes in a dark room. In brighter scenes, you could see the bright parts of the image, but not very well. It's nowhere near as good as the 50Watt halogen, but that's to be expected.
So, unless you want to use a large LED array for the bigger LCD panels, or unless we can find a fairly cheap super-high brightness LED module, I don't think you can use these "simple" LED solutions for commercial projectors very easily at all. Of course, people have had success with using huge LED arrays on 7 inch screens though.
Oh well, it's early days for me yet and I'm still looking for other LED candidates for modding commercial projectors with. LED technology is getting better every month, so it won't be long before the prices start coming down and the LED modules get small and bright enough.
The high-power LED modules from Edison Opto look very promising. I just need to e-mail them now to see if they'll give me a price on them. 😉
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