When an Infrared (IR) remote sends its signal across the room, you can’t see it with your naked eye. Nor can you see when an unlabeled fiber optic cable is live. And testers are unpleasantly expensive.
That’s what this article will solve Fear not. You might be sitting on the answer right now. Because the answer is the camera on your smartphone. Most smartphone cameras can “see” IR and other wavelengths our eyes cannot see.
In order to do that, Just aim your smartphone camera at the IR emitter on a
remote and press the button. If it’s working, you will see the emitter flashing on the phone’s display.
And To find an un-labeled fiber optic pair attached to a device, aim the camera at the other end of the cable. You should be able to see the laser signal from the device at the end of the cable on the camera’s display. Never attempt this with your unprotected eye, as lasers can harm your eye.
If you try this, please comment how it solve your problems down below.