kevmac Posted March 12, 2007 Share Posted March 12, 2007 -------------------------------------------------------------------------------- I am trying to find a really bright infra red led. It needs to be arround the 950nm spectrum so it is invisible to the human eye. I need to provide illumination for a black and white ir sensitive camera. It only needs to illuminate a distance of about 1 metre and powered from a 12v dc source. I can only use 1 led. I have tried a few from Maplins electronics with what i think is the right resistor, but i only get a very dull glow. Nowhere near enough to illuminate anything from 1 metre. I have tested the camera using the light from a domestic IR remote control which nearly gives enough light. Can anyone suggest a 3mm or 5mm ir led and the correct resistor ? the camera specs don`t give me the iR frequency response but it does react to a domestic ir remote control. Link to comment Share on other sites More sharing options...
Doktor Jon Posted March 13, 2007 Share Posted March 13, 2007 --------------------------------------------------------------------------------I am trying to find a really bright infra red led. It needs to be arround the 950nm spectrum so it is invisible to the human eye. I need to provide illumination for a black and white ir sensitive camera. It only needs to illuminate a distance of about 1 metre and powered from a 12v dc source. I can only use 1 led. I have tried a few from Maplins electronics with what i think is the right resistor, but i only get a very dull glow. Nowhere near enough to illuminate anything from 1 metre. I have tested the camera using the light from a domestic IR remote control which nearly gives enough light. Can anyone suggest a 3mm or 5mm ir led and the correct resistor ? the camera specs don`t give me the iR frequency response but it does react to a domestic ir remote control. Hi kevmac and welcome, The remote control LED is almost certainly working better, simply because it's light output is at a lower frequency, which is better suited to the cameras imager. With most cameras, by the time you get to 950nM on the spectral response, there isn't that much to talk about (perhaps 5 - 10% sensitivity on average). I haven't used individual LED's in ages, but when I last did, they were TSIP 9600 series (I think...?), with a single device being driven from 12v DC through a fairly chunky ceramic resistor. You should be able to find suitable LED's quite easily, but depending on what your pointing the camera at, you may need to use a few just to increase light output sufficiently to offset the problems of camera insensitivity. If I can find any useful info, I'll post back. Link to comment Share on other sites More sharing options...
kevmac Posted March 13, 2007 Author Share Posted March 13, 2007 Thanks for that. I have found some 850nm leds on the RS website (part no 455-0802) I will give them a go. At what point does the visable light drop out. I thought it was above 850nm ? What is the usual output of a domestic ir control? If you can recommend any high output ir led i would be grateful. Link to comment Share on other sites More sharing options...
Doktor Jon Posted March 13, 2007 Share Posted March 13, 2007 Thanks for that.I have found some 850nm leds on the RS website (part no 455-0802) I will give them a go. At what point does the visable light drop out. I thought it was above 850nm ? What is the usual output of a domestic ir control? If you can recommend any high output ir led i would be grateful. Afternoon kev, You mentioned that you've tried a LED from Maplins ... was it this one ...? http://www.maplin.co.uk/Media/PDFs/yh70m.pdf LED's generally have a very narrow spectral output, so for example, the one above is emitting between 915nM and 965nM, with peak output optimised for 940nM. In answer to your question about light drop out, it isn't the peak IR output you are seeing, but rather the high end (barely) visible red frequencies that are at the lower end of it's spectral emission. So in order to go covert, you have to go up in emitter output frequency to ensure that it's lower limit remains invisible ( that sounds so complicated, I'm beginning to confuse myself now ). Just for future reference, LED's output a much narrower spectral output than 'bulb' based IR illuminators, whose filters can in some cases pass much more than is needed. I don't know what TV manufacturers use in their remote controls, but I would imagine it's somewhere around the 850nM+ output. If you have a link to the RS diodes, it would be interesting to see what they offer these days. D.J. Link to comment Share on other sites More sharing options...
kevmac Posted March 13, 2007 Author Share Posted March 13, 2007 Yes that was one of the leds i tried..........didn`t work very well I am hoping that by dropping down to 850nm i might get a better response these are the spec sheets http://docs-europe.electrocomponents.com/w...66b8025c31a.pdf (rs part no 455-0802) and http://docs-europe.electrocomponents.com/w...66b80325c6e.pdf (rs part no 455-0818) Do you think its worth trying them ? It would be easier if the camera specs told me the frequency response....but it doesn`t. I have used loads of cameras with the built in infra red emmitters but i don`t know which ones they use. Link to comment Share on other sites More sharing options...
Doktor Jon Posted March 13, 2007 Share Posted March 13, 2007 The OPE 5587 has half the width coverage of the other LED, so in theory if they both output the same amount of energy, the 5587 should work better, although depending on the lens fitted, you may see a brighter lit area in the middle of the picture. The camera would almost certainly be more efficient at 850nM than 940nM, so given the same energy output from the light source, the picture should look brighter. Getting the resistor value just right is quite important; too low and the light output will fall off significantly, too high and you will probably kill the LED (even 0.1 volts difference can be noticeable). These devices are usually designed for pulsed operation, which allows a higher light output without cooking the device, but to be honest, given that they really only cost next to nothing, you might just as well have a play around and see what works for you. Have fun, and let us know how you get on Link to comment Share on other sites More sharing options...
silicon skum Posted March 14, 2007 Share Posted March 14, 2007 Most common CMOS and CCD based cameras have a higher sensitivity to IR at around 845 - 850nm, unless they are designed to work deeper into the IR range. If you want to optimize the IR sensitivity of your camera, you should try to find out what image sensor it uses and look up the spec sheets for the sensor (available from either the part manufacturers website or a number of other websites that deal with parts or list specs sheets). A quick Google search should give you all the info you need. Also you might find the IR LEDs on this webite of use (includes spec sheets). : http://www.roithner-laser.com/LED_HP_multi_chip.html These are multi chip packages, VERY bright (not a good idea to look directly into...) SS Link to comment Share on other sites More sharing options...
Allan Posted March 14, 2007 Share Posted March 14, 2007 --------------------------------------------------------------------------------I am trying to find a really bright infra red led. It needs to be arround the 950nm spectrum so it is invisible to the human eye. I need to provide illumination for a black and white ir sensitive camera. It only needs to illuminate a distance of about 1 metre and powered from a 12v dc source. I can only use 1 led. I have tried a few from Maplins electronics with what i think is the right resistor, but i only get a very dull glow. Nowhere near enough to illuminate anything from 1 metre. I have tested the camera using the light from a domestic IR remote control which nearly gives enough light. Can anyone suggest a 3mm or 5mm ir led and the correct resistor ? the camera specs don`t give me the iR frequency response but it does react to a domestic ir remote control. Hi Kev There is a guy on Ebay that sells an IR Floodlight that is invisible to the human eye (Not the usual Glowing Red ones) and if you ask him he will send you a picture of the light in action here is the link http://cgi.ebay.co.uk/140-led-IR-Illuminat...1QQcmdZViewItem Regards Allan Link to comment Share on other sites More sharing options...
Doktor Jon Posted March 14, 2007 Share Posted March 14, 2007 Interesting links chaps Link to comment Share on other sites More sharing options...
kevmac Posted March 15, 2007 Author Share Posted March 15, 2007 I have tried the 850 and 880nm LEDs. They are brighter but still no where near as bright as the light given off by my IR remote control. which is in the invisible ir range. So there has to be a LED out there that will do it but i just can`t find it I may resort to ripping my remote control to bits ! and using that....but how would i know what resister to use, if i dont know the specs for the led. the camera is this one Order Code: 4142913 FARNELL Manufacturer: HERO Manufacturer Part Number: MO-S412-3C http://www.farnell.com/datasheets/38010.pdf http://uk.farnell.com/jsp/endecaSearch/par...jsp?SKU=4142913 I can`t find any info for its frequency response Does anyone know of another uk supplier for this camera as farnell are discontinuing it !! Link to comment Share on other sites More sharing options...
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