Hi all , I found some IR LEDs and it seems like the company has stopped manufacturing this model , it is everlight IR333-6c , I googled it and I found some similar models from the same company , however mine wasn’t there , I observed that many of their LEDs are of the same specifications , so this is one of them http://kr.ic-on-line.cn/IOL/viewpdf/IR333C-6-A_586780.htm , please I wanna know if this is good for FTIR.

As they mention “Peak Wavelength” is 940nm...is that you want? 940nm?

hi papakion , I don’t think it will make a big difference - or does it ? - , so lets say it is ok , but I’m talking about the viewing angle , the electricity stuff(current , voltage etc ..) , I wanna power it with a PC Power Supply , I just want to make sure it will work fine before buying.

hey Mrme

The viewing angle as I see is small , only 20 degrees. The voltage they need is 5V and they are driven by 100mA current. I was talking for the wave length cause if you have already purchased i.e. band bass filter for you camera on 850nm, then these won’t fit you.
In my opinion, these are not good LEDS for your table

thanks for the reply papakion , well to put you in the picture ,it is very hard to find IR LEDs in my country regardless of their wavelength , thanks to god finally I found those , band pass filter is a dream for me,so I’m gonna use an exposed film , 20 degree is small right ? , what about decreasing the distance between the LEDs ? like every 1 Inch would it be a good workaround , my main question , would these LEDs somehow work for me ?.

I hope others can say their opinion before you buy them. If I were you, I wouldn’t buy them

Hi mate glad to see you decided to work after thinking
The main characteristic for LED is its viewing angle and power dissipation and mostly its radiant intensity. I think radiant intensity parameter is good (85 mw/Sr in 100mA) power dissipation is 150 mW is good but viewing angle is low (I think it is full angle not half angle) if you read Sfh 485 datasheet it’s viewing angle is 20 but there , 20 degree is it’s half viewing angle and in total it is 40 and it is ideal for FTIR but I couldn’t find right proof for your LEDs full viewing description.
You know Mrme we have same problems It took 1.5 month for me to find proper LED in my country and for finding that I even traveled to two other city and after digging and searching a lot I found it in my city (they are Sfh 485p).so don’t be disappointed you can find Leds better than these. If you couldn’t then you have no choice. These leds are good but I doubt a little to their viewing angle.  how much does it cost for you ?
Why band pass filter is your dream? Is this because of constraints or your badge?
If it is because of budge why you don’t bulid a LCD-FTIR one?
Over all I am ready to help you more because we have common pains
Good luck

thanks vahid for the reply , well I did find another LEDs , but the problem is the specifications , they all just throw the specification paper or the box the LEDs come in and just the keep plain LEDs , Budget is not really an issue yet , and for the LEDs cost , it is about 30$ for 100 LED , I will keep you updated , thanks again

I would not use a piece of film to filter 940nm LEDs

you can see from this thread that it will cut out about 65% your light . 
http://nuigroup.com/forums/viewthread/6458/

Negative film is better for 850 and 880nm LEDs]

Here is a pretty picture of what I’m talking about:

Firstly let me correct someone that posted here
These are NOT 5V LEDs (that is peak tolerability there isn’t such thing as a 5V LED - look here for the myth of the 5V LED : http://led.linear1.org/myth-of-the-5-volt-led/

This is a 20 degree angle 1.2V 20mA LED

The angle is bad, I am not sure if you can angle them 20 degrees to get what you want…

Also, combine this with the fact that your camera probably isn’t going to see 940nm light very well anyway.  There are many posts about this.

Once you take this into consideration you will realize that ONE 850nm LED will be brighter than TEN 940 nM LEDs with a piece of negative as your filter.

Since you wouldn’t build your setup with 3 LEDs per meter, I don’ think this would work either.

Don’t use these LEDs they are a waste of your time and your money.  Do you really want to set up a table with no light, but all the work?

Thanks for the feed back , I’m really “totally frustrated internally “ , the main problem is that I’m not even sure if those were the right specifications ! , I guess I should experiment with a little piece of Acrylic - already exist - before buying for the big piece. thanks again

You should be able to angle the LEDs 50 degrees and that would work.  I just don’ think 940nm wavelentth LEDs are the way to go. your camera sees 880 or 850 or 830 much better.

Mrme, I have stock of 850nm LED strip in Europe. The cost is £25 per 50cm. I also have the flexible connectors for the corners of the acrylic, and fused connectors to attach to the power supply. 3 flexible connectors and one fused terminator costs £10 so 2 metres of LED, enough for a 22” surface will cost £110 plus shipping to your country.

Thanks

blu