IR (infrared) LEDs: please explain these to me.

I've seen infrared LEDs such as the osrams, and I don't have any idea how they work. Do you need special goggles or glasses to view them? Is this expensive equipment?

I just need a basic rundown of how these LEDs work.

You will either need a camera that can see IR or some sort of IR sensitive night vision gear. I have typically used IR as an illumination source for modified IR still cameras.

I have not built my own illumination array yet, I would assume that using similar drivers as flashlights they would work fine. You would likely also want to remove any visible residual red glow with a proper bandpass filter that will only allow the wavelength you want out of you source light.

Matt

I’ve got an infrared dropin for SolarForce and using it in conjunction with my cell phone it’s my cheap night vision. I find that over half of the cell phone will display the infrared. You can test those phones with any TV remote. If the camera picks up then it’s a go.

they are just as any other type of led you know, just emitting electromagnetic waives that are just behind the normal spectrum of electromagnetic waives the human eye can detect.

basically every type of driver suitable for ordinary led will work for IR led too. look at them as an ordinary led an apply to them all you know on other led if you plan to build something.

Is there some kind of relatively inexpensive glasses I could use with these?

Our eyes are only sensitive to a small part of the IR band and low band IR extends from around 740nm to around 1000nm and well beyond. Some people can see into the very low 730nm range ov near IR. The best ways to “see” are to use a “CMOS” or other MOS technology cell to see it and convert it to something our eyes can see. This can be done with some cell phones, point them at your TV IR remote and activate the remote, you may see it blink out codes. Also the are crude mods to digital cameras that will allow it to be seen and there are high end mods that still allow the camera to focus and see less normal light. IR has a shifted focal point compared to the visible spectrum. And then there is full on IR night vision, this operates at very specific frequencies and works as a mated transceiver pair.

IR spectrum

Dash-cams, even the cheap ones, have an “IR-cut” filter in them, usually a coating on the innermost part of the lens. Remove the coating and you’ve got an IR cam. Look for a cam which does at least 720P (not 720PI or Pi). Ten minutes work, $30 cost and the visual end is in business leaving you $$$ to make the illuminator. Some guys have used a pair of dash-cams carefully mounted ala “google cardboard” style for binocular viewing to make night vision goggles on the cheap. It’s on my project list :slight_smile:

Phil

They emit Infra-red light wavelength that is outside what our eyes can see, but many cameras can see that range quite well. ( IR on the opposite side of the visible light spectrum as UV is, closer to the radio wave side.
(dashcams, some video cams, security cameras, etc. Also they are used in TV remote controls, security zone sensors, Wildlife tree-cameras, the list goes on.

one in a flashlight will emit a very, very faint barely visible red glow, but turn that flashlight on in front of most video cameras and security cameras and it looks like a regular flashlight to them.

Hmmm. I wonder how an iPad camera would do. They don’t come with a flash, so they’re designed to work well in low lighting.