# Is there a "filter" that will make an infrared light source visible? **URL:** \ **Category:** Factual Questions\ **Created:** [June 3, 2004, 3:18pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458 "2004-06-03T15:18:25Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![aaelghat](https://avatars.discourse-cdn.com/v4/letter/a/c5a1d2/32.png) [@aaelghat](https://boards.straightdope.com/u/aaelghat)\ **Post date:** [June 3, 2004, 3:18pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458/1 "2004-06-03T15:18:25Z")
My goal is to be able to see the infrared light source on a lost remote control. A button is stuck on the remote, and it’s causing interference with one of my components, but for the life of me I don’t know where the remote control is. I don’t have access to night goggles or a camera that will capture infrared, so I want to do this on the cheap. I do have access to a digital camera however. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [June 3, 2004, 3:27pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458/2 "2004-06-03T15:27:01Z")
Your digital camera or camcorder will see it. Use the LCD monitor on the back of your camera. If you point it at a remote control with the button pressed down, you will see the infrared signal as a pulsating white light. Try it on one of your existing remotes. Thing is, you have to point it at the front of the remote. It’s not like you can see the “rays” of infrared or anything. So, chances are, you’ll find it in plain sight before using this method. ---
**Author:** ![dwc1970](https://avatars.discourse-cdn.com/v4/letter/d/a183cd/32.png) [@dwc1970](https://boards.straightdope.com/u/dwc1970)\ **Post date:** [June 3, 2004, 3:27pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458/3 "2004-06-03T15:27:56Z")
You don’t need a special camera to see the infrared emitted from a remote control. Any video camera (at least the ones I have used) will pick up the light from an infrared remote control, so if you have a regular video camera then this might work. The light from an infrared remote control appears on a video camera as a blueish white light. You will have to be in front of the remote sensor to pick up the light, and the room would have to be dark, too. Since you mentioned the button on this remote is stuck then the battery will likely run out of power before too long anyway. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 3, 2004, 4:10pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458/4 "2004-06-03T16:10:16Z")
Your remote probably uses an IR LED, and those typically emit below 1 micron, so, yeah, a lot of video cameras will see there. Longer wave IR gets more difficult – you can’t pull the same trick you can with UV light, where you make something fluoresce, since the IR light photons have _less_ energy than visibvle photons. Some interesting dodges are to use a UV source to illuminate a screen, which the IR light can add enough to just kick things over the edge. We had an IR spectrometer that worked like that. Other ideas are to use heat-sensitive material to pick up the heat from the IR source. Those liquid crystal thermometer sheets that Edmunds sells are great for that. Edmunds also sells a couple of IR viewers, one of which goes much farther into the IR than you’d want. ---
**Author:** ![GreyWanderer](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@GreyWanderer](https://boards.straightdope.com/u/GreyWanderer)\ **Post date:** [June 3, 2004, 4:51pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458/5 "2004-06-03T16:51:47Z")
> [@pulykamell](#): > > Thing is, you have to point it at the front of the remote. It’s not like you can see the “rays” of infrared or anything. So, chances are, you’ll find it in plain sight before using this method. Unless you turn off all the lights and fill the room with lots of smoke (; ---
**Author:** ![FX45\_4Ever](https://avatars.discourse-cdn.com/v4/letter/f/4bbf92/32.png) [@FX45\_4Ever](https://boards.straightdope.com/u/FX45_4Ever)\ **Post date:** [June 3, 2004, 5:19pm UTC](https://boards.straightdope.com/t/is-there-a-filter-that-will-make-an-infrared-light-source-visible/248458/6 "2004-06-03T17:19:12Z")
I’ve heard couch cushions have been able to press buttons when people sit ontop of remotes lost in the couch.