What you need:
A webcam. Some exposed and
developed film negative (the black part at the end of a roll of film), the inner bit of a floppy disk or some unexposed, but developed colour slide film.
Doing it:
Very carefully unscrew the screws holding the plastic casing together and take it apart cautiously. Well done, you have just voided the warranty on your webcam, so no going back now. Different webcams are put together differently, but the idea here is to remove the casing holding the lens in place. Once this is done you’ll be able to see the CMOS sensor. Whatever you do, do not touch it.
Now dismantle the lens casing and find the IR filter. If you hold the lens assembly up to the light it will have a slight red tinge to it. The filter may be a separate component, in which case you can simply remove it, or it might, as with mine, be
integrated into the lens assembly. You can still remove it, but you will have to break it out. Be careful when doing this, otherwise you will end up sticking a screwdriver or similar pointy object through the lens.
Now all you need is an IR pass filter. It will not be a perfect filter, but for our purpose, it will do. To construct the filter, mount a piece of film or floppy disk so you can put it in front of the lens. I used an old slide holder I dug out of a cupboard.
Now just plug in your camera and, once you have a source to illuminate objects with (such as your TV remote), you can look at the effects with your new IR webcam. As all objects that emit heat also emit IR light, your IR camera will pick up the IR from hot objects, like a soldering iron.
Some types of ink will not show up under IR light, like the red on this playing card. It is the seven of hearts, but under IR light the card appears blank.
