Jon, please let us know if the suggestions for ‘Ideal LEDs’ above were made in time.
If they were and you get information on current and future LED specs (datasheets preferably), that would greatly help the community. Thanks again!
They were indeed. I don’t think we can really control the radiant intensity or angle. He said the current angle is 120°, but he can’t really shrink it without introducing cost. He is ordering a batch of 850, and is thinking of switching to it once we get positive results.
Here is one of his emails to me:
All our ribbon is full angle 120. (Of course, since you’re getting technical, I’d have to tell you I’d have to guess that beam edge is 50% of Center Beam Candle Power. Not totally sure, but it seems like most people call the beam edge at 50%.) I have no control over angle, but it’s in your range, so we’re done with that.
Regarding intensity, I have no control. I’ll see if I can find out. Manufacturing at 850 nm will probably be far more important than trying to find brighter LED’s. The wavelength is a lot easier to tweak (I believe-assuming I can find the LED’s) than the intensity. If I used High Brightness LED’s (assuming they actually exist for IR), a) they’d be really expensive, but even worse, b) I don’t think we could get the heat out and they’d fail early.
As for electrical specs, not too important for you guys, I don’t think. It’s more the optical properties. Besides, I don’t have the electrical. I did measure power consumption and read 30 watts per reel for the 940.
These specs have worked well for us so far (at both 940 and visible white)… The strips are basically designed to light up acrylic.
Jon, please let us know if the suggestions for ‘Ideal LEDs’ above were made in time.
If they were and you get information on current and future LED specs (datasheets preferably), that would greatly help the community. Thanks again!
They were indeed. I don’t think we can really control the radiant intensity or angle. He said the current angle is 120°, but he can’t really shrink it without introducing cost. He is ordering a batch of 850, and is thinking of switching to it once we get positive results.
Here is one of his emails to me:
All our ribbon is full angle 120. (Of course, since you’re getting technical, I’d have to tell you I’d have to guess that beam edge is 50% of Center Beam Candle Power. Not totally sure, but it seems like most people call the beam edge at 50%.) I have no control over angle, but it’s in your range, so we’re done with that.
Regarding intensity, I have no control. I’ll see if I can find out. Manufacturing at 850 nm will probably be far more important than trying to find brighter LED’s. The wavelength is a lot easier to tweak (I believe-assuming I can find the LED’s) than the intensity. If I used High Brightness LED’s (assuming they actually exist for IR), a) they’d be really expensive, but even worse, b) I don’t think we could get the heat out and they’d fail early.
As for electrical specs, not too important for you guys, I don’t think. It’s more the optical properties. Besides, I don’t have the electrical. I did measure power consumption and read 30 watts per reel for the 940.
These specs have worked well for us so far (at both 940 and visible white)… The strips are basically designed to light up acrylic.
Sounds good Jon.
Many of use are researchers, electrical engineers or need to make sure we are optimizing our setups. If there’s any datasheets or the electrical specs (that he said we thought we might not need) that you could get, that would be great. For the enthusiast, it’ll be enough to know that ribbons are easy and they work, but for people really wanting to pursue high levels of optimization and research, they’ll need all the information about the parts they are using.
Sorry, if I’m being picky lol. This is all information for the long run. It’s great that the angle and wavelength look to be in the ideal spec. Hopefully we can get measurement or measure ourselves the intensity so we truly can compare these ribbons to other LEDs used on the forum. A low radiant intensity could mean the different between using 1 LED vs. 2 LEDs.
I have a off the wall question. I’ve seen people using large screens in there set up, about how large of a screen can you go and have the middle still be effective? I’m asken because someone offered me a large used LCD monitor for a decent price. If it’s too big to use I rather find out first hand befor I go buy it.
J[e]sus and Shadeling, we put the ribbons on 2 sides (not all 4) in the shape of an “L”. I think the big difference with these strips is the sheer number of LEDs on them. It really does “flood” the acrylic with light. When viewed with the IR camera, you can see a glowing IR rectangle around the entire perimeter, and it doesn’t appear to be significantly lower in intensity (compared to the sides that have the ribbons on them).
I suspect for a super-large display, you may want to wrap the entire perimeter, but I would test it first, it may not be necessary. Buy a length of ribbon suitable to wrap the entire perimeter. Don’t cut it up yet, and just wrap 2 of the 4 sides, holding the ribbon to the acrylic with some bits of tape. Plug in the ribbon to the power supply and test some blobs on the acrylic. See if there are any weak spots in the opposite corner that has no ribbons immediately around it. If it’s fine, you’re probably good with the “L” shape. If not, wrap the rest of the ribbon around the 4 sides and see if it helps (it should).
You can also do this kind of testing with visible light. In fact, I highly recommend getting a length of white light LED ribbon for this purpose. This isn’t the best photo, but it shows how you can quickly wrap a ribbon around the acrylic and see the blobs with your own eyes. Granted, it doesn’t factor in the differences in wavelength and intensity, but I don’t know how significant that is. It certainly helped us test compliant surfaces though.
Hi Jon thanks for all your efforts in ascertaining the correct IR ribbon for FTIR… i saw this picture on your website
it looks like the manufacturer is using a regular SMT packaged LED… Currently in my setup im using OSRAM SHF485 they have the following specifications
Half Angle +-20degree
Radiant intensity 160mW/sr @100mA
In the search of a comparable SMT packaged LED i found these Osram SHF4259
these are the basic specs
Half Angle +-25degree
Radiant intensity 80mW/sr @100mA
Link Data Sheet
I also found Osram SHF4650
Half angle +-20degrees
Radiant intensity 125mw/sr @ 100mA
Link Data Sheet
2 works great for us… but I don’t see any reason you couldn’t do 3. If you did 4, then it might make the frame harder to disassemble for cleaning and repair and such.
Many of use are researchers, electrical engineers or need to make sure we are optimizing our setups. If there’s any datasheets or the electrical specs (that he said we thought we might not need) that you could get, that would be great. For the enthusiast, it’ll be enough to know that ribbons are easy and they work, but for people really wanting to pursue high levels of optimization and research, they’ll need all the information about the parts they are using.
Sorry, if I’m being picky lol. This is all information for the long run. It’s great that the angle and wavelength look to be in the ideal spec. Hopefully we can get measurement or measure ourselves the intensity so we truly can compare these ribbons to other LEDs used on the forum. A low radiant intensity could mean the different between using 1 LED vs. 2 LEDs.
Thanks again for your patience and helpfulness!
Yeah, we are researchers as well… but we are researching interaction models, so we just need a setup that just works, and is easily configurable. I could see where you would need more control though. I would recommend contacting Greg yourself and explaining your situation… he has been very open and helpful to us.
Oh, I believe you asked about syncing the IR to the camera earlier. I notice about a 2-3 second delay from when we plug in the strips to when they light up… but I believe that is do to our power supply. Greg did mention that if we wanted true dimming, we needed to use one of his supplies that turned the lights off and on for fractions of a second (the same way choosing the power setting on a microwave works). This makes me believe that it is possible to turn the LEDs on and off at a high rate of speed… though you would need a custom controller for that (shouldn’t be too hard to build).
I have a quick question myself, do you know who is writing the new MacTracker? I would like to share code with them if possible. It is apparent that the current software isn’t up to par, and we have 3 different ideas for how to deal with this… if someone else is working on the same thing it would be good not to reinvent the wheel. I plan to start working on it as soon as I get my iPhone app out the door.
Thanks Jim, But lookes like I wont be able to get it. I was a 60"+ LCD screen that installed into a table with black smoke glass over it in a confrence room. They were replacing it because the back light went out on them. But someone had butter fingers whey were un-installing it. :(
Great news from Greg at EnvironmentalLights.com. He’ll be carrying two IR LED ribbon products, an 850nm and a 940nm version. He’s expecting inventory on both of these by September 4. Right now, since there were a bunch of orders placed, I think he just has a bunch of 940nm samples (up to a foot or two in length).
You can also find waterproof versions of all the above products. The waterproof version has a thin rubber sheath around them, which allows them to be used outdoors for security lighting.
He linked to our videos on the product pages, which is pretty cool
Bila, the acrylic we used was 24” x 18” x 3/8” thick. If you use the aluminum channels and LED ribbons from EnvironmentalLights.com, that is the perfect thickness. It pairs well, and has just enough space for a layer of Sulky Solvy, and a layer of Rosco, with some double-sided tape in between each. The frame fits pretty snug around the “sandwich”, but isn’t so tight that it’s hard to slide things in and out.
Yeah, we are researchers as well… but we are researching interaction models, so we just need a setup that just works, and is easily configurable. I could see where you would need more control though. I would recommend contacting Greg yourself and explaining your situation… he has been very open and helpful to us.
Oh, I believe you asked about syncing the IR to the camera earlier. I notice about a 2-3 second delay from when we plug in the strips to when they light up… but I believe that is do to our power supply. Greg did mention that if we wanted true dimming, we needed to use one of his supplies that turned the lights off and on for fractions of a second (the same way choosing the power setting on a microwave works). This makes me believe that it is possible to turn the LEDs on and off at a high rate of speed… though you would need a custom controller for that (shouldn’t be too hard to build).
I have a quick question myself, do you know who is writing the new MacTracker? I would like to share code with them if possible. It is apparent that the current software isn’t up to par, and we have 3 different ideas for how to deal with this… if someone else is working on the same thing it would be good not to reinvent the wheel. I plan to start working on it as soon as I get my iPhone app out the door.
Yeah, I meant researchers in the hardware department specifically in that reply . We have all types of researchers on the forum. While many are software researchers, others are hardware researchers. There’s really some math and calculations to building the optimal FTIR display and knowing numbers can really affect the outcome. I appreciate how attentive you’ve been. =)
Thanks for the pulsing info. =)
As for a MacTracker, you’ll have to be more specific. Recently we’ve seen a boom in new trackers for multitouch. There’s BBtouch, and the new release (a couple days old) called Touche. Both of these are mac only trackers. We’ll also have a new tracker (featured on the main page of nuigroup) that will be cross platform (win/mac/linux) and be the new core tracker of the community (hopefully). Which one would you be referring to?
