In this video I modify a pair of halogen projector fog lights to be infrared illuminators.
The lights use 55w H3 halogen bulbs which are small, cheap and put off quite a lot of visible and IR light.
I had a local shop cut oval shapes out of a small sheet of 3mm acrylic IR pass filter. This filter lets infrared pass through but blocks visible light.
Once the IR pass filter was inserted inside the lights, they were sealed back up. Unfortunately the filter oval needs to be sat in a specific position to create a perfect filter inside the light and on one of them I got this wrong and a little visible light is being emitted. It’s a fairly simple fix, I just need to open the light, turn the filter into the correct position and then seal it back up again.
They put off a fair amount of IR light and cover a very large area. But for my specific requirements, they’re not what I’m looking for.
To the human eye they have a very dim red glow inside. They appear brighter on my camera since it’s a little IR sensitive.