On Friday just gone, I decided to carry out something of an experiment with an old Webcam, a Phillips model where the lens assembly simply unscrews making life a lot easier for my experiment. 

The background - Most digital camera’s have a sensor which is capable of seeing “near” infra-red - however when they are shipped they have a small usually square translucent filter in line with the lens to block this out, as it can impact the quality of the picture when decoded onto the computer - allowing for a more realistic reproduction of the visible light.

The challenge - Basically to reverse the functionality so that it ONLY allows the “near” infra-red portion of light through.

So - anyways, I quickly took the lens assembly apart with the aid of a small screwdriver for leverage and located the offending filter….actually it just fell out :P  In order to block out visible light I took out some old holiday snaps and looked for a bit of underexposed developed film - this is the bit that looks black; and I cut two pieces the same size and shape as my infra-red filter (as these are perfect for blocking visible light whilst still allowing infra-red through) - these got put back in the lens assembly and I pieced my camera back together.

Connected it up and tested it, initially I couldn’t see enything - that is until I fired up a TV remote in front of the camera and it shone like a bright torch!!  I’ll grab a screen shot of this and post it later.

Moral of experiment is, whilst we cannot visibily see “Near” Infra-red with our eyes, and our eyes don’t physically react to it, it is still powerful enough to damage our eyes and can even burn the retina, so once you see the picture result of my little experiment you will hopefully learn that it is dangerous even to look at the end of an ordinary TV remote control!