Behind what materials can a IR emitter transmit? I want to create a plastic casing with one color and want to avoid a black stroke on it. Is that possible somehow? Can it be anything other than those black pieces on remotes?
The “black” pieces you’re referring to are actually clear/translucent material that has been tinted to block visible light, but allow the IR light to pass through.
This is done to visually hide it, but it also helps filter out other light noise that could falsely trigger the IR sensor.
It is possible to shift that color slightly, but black tends to be the best because it hides itself the easiest. For example take a look at the front of a black cell phone and you probably won’t even see the IR emitters (used for proximity detection on calls). If you compare that to a white phone (even the iPhone) you’ll see the tint shift where the transparent areas are.
The surface also needs to be polished generally since any texture or surface flaws would scatter the incoming signal.
Thanks! I was wondering if the translucent part could be a bright red or sky blue. Probably not… Have anybody seen such a product?
There is a little confusion here. Maybe only on my part.
The emitter can be behind any clear/tinted material that does not block the infrared waves. It does not need to be “black”. The “bulb” itself is typically clear. Since it is an emitter, light noise does not matter.
An infrared receiver does typically comes tinted to a specific frequency, reducing light noise false positives as you wrote. I read your post as the emitter also needs a tint when it doesn’t.
Sorry I was referring to the whole thing as an assembly, since usually they are paired one way or another.
Yes, the emitter needs nothing, but can still be behind tinted plastic.
The receiver does not need a coating. A completely packaged receiver already has the tinted coating on the outside of the lens (like you’ve shown) so in that case, you don’t need the coating you just need to NOT block the light you want with your surface pigment. The outer housing tint is purely cosmetic at that point.
Black is usually just the easiest way of getting there and color matching surrounding surfaces.
There’s the confusion. I am currently working on a project where the emitter is in a separate housing from the receiver. Actually, there is one emitter per room and a receiver on each person. A big brother tracking system if you will.