MAKING OWN IR CAMERA

The camera

The camera used for this experiment was a Sweex USB Webcam this camera was chosen for it's price and availability. IE I didn't mind too much if I killed it and it was sat on the desk at the time.

The adverts at the top should show some providers of cheap webcams, and buying from these people will help to pay my hosting costs.

As an added bonus, but nothing to do with this project, this camera works fine under Linux with a 2.6 Kernel (I'm using 2.6.8) using the sonixcam driver from
here
.

Conversion

Step 1 (Sweex specific)

Remove the crappy plastic stand. - try not to lose the little rubber bits from the holes in the camera sides. I think they are supposed to stop it from tilting upwards under the weight of the wire. Shame they don't work really.

Step 2 (possibly also Sweex specific)

Remove the screws. If your chosen
victim
webcam is held together in some other way you'll have to figure it out yourself.

Step 3 (Probably not Sweex specific)

Prize the casing apart.

Step 4 (Kind of Sweex Specific)

If the Lens will not unscrew without removing the PCB (Like on the Sweex) then remove the PCB. It probably only slides in anyway.

Step 5 (Almost certainly not Sweex specific)

Unscrew the lens assembly from it's holder. The focus on most webcams is achieved using the screw thread that is also used to hold the lens in. Turning it enough times will unscrew it completely. All camera's I've ever met won't let you do this without opening the case. The bit that comes out of the sweex looks like this.

Step 6 (Doesn't appear to be Sweex specific)

Looking at the lens assembly in the picture you can see a small square of glass stuck in the back. Though it appears clear in the picture above, it has a red tint to the eye as shown here.






I've looked in a Creative camera and seen the same thing there but theirs is round. This piece of glass is the Infra Red Filter. It stops IR light getting through to the sensor. For our purpose this is bad so remove this piece of glass. Removing a square one like the Sweex is easy but I suspect the creative round one is harder.

Mitch White has this to say on the Alaris weeCam ...the filter is actually "painted" on one of the lenses. At first I thought I wouldn't be able to remove the filter, but I tried scratching at it with my fingernail, and it started to come off! So, after scratching off all the redish stuff, I reassembled the camera and it works perfectly!


Ken R has converted a Creative camera though not the same as mine. Click here for his instructions on adapting the lens assembly.
Newer Sweex models and many others have a lens design with a cross section like this.






On here, the red is the IR filter, the green bit on here is a small plastic collar that holds things together. It looks at first glace like the same piece of plastic as the main lens holder assembly. This can be removed by levering it out with a sharp knife. This collar can be used to hold the new IR pass filter in place later.

Step 7 (Not at all sweex specific)

Now we need to make a new filter only we want one that blocks visible light and only lets IR through.

Dig out your holiday snaps and look at the negatives. NOTE: they must be colour negatives, black and white ones won't work. Find a bit of absolute black, you can usually find a bit before the real photo's start. Make sure it's really black, a part of a normal photo may not be good enough.

Cut two small bits out similar in size to the IR filter that you just removed.

Step 8 (Also not at all sweex specific)

Fit the two bits of film where the old filter was.

Step 9 (No idea if it's Sweex specific)

Do something to hold the bits of film in place. I used a little bit of wire as shown rather blurredly here. If you use superglue for this be careful not to get any on the actual lens or the part of the negatives that the IR light will pass through.

Step 10 (I'm getting fed up of saying whether it's Sweex specific or not.)

Screw the lens back into the camera PCB.

Step 10

Re-assemble the rest of the camera.

Step 11

Make sure you're using real sunlight or tungsten lighting. Those new fangled high efficency bulbs give out very little IR light.