Thanks for the reply Ron. So you're saying that both filters are high pass filters. If the sun doesn't cause much noise in the higher frequencies then I guess that would work. However if it does, I need to design a better circuit, such as a bandpass filter with high Q to isolate my signal. Is this correct?
I did try IR filters. The material I tried is exposed, developed, photgraphic film. From what I've read the transmission of IR is centered right around the 900-1000nm realm but not tightly centered. I'm sending 940nm IR. However, the range was only increased a few feet. I should note however that this was using an incandescent light bulb to simulate sunlight, which seems to duplicate the problem quite well, as we haven't had any strong sunlight here for the last week. It seems plenty of stray IR is still getting in and flooding the IR module. I can't find a comercially available IR filter that is centered tightly on the 940nm. The only thing I've had real success with is using small tubes as recessed cavities for the IR module. The problem is, I need the full field of view of the IR module for my application. That's why I'm looking into inductance type filters to help. Is it possible that the light bulb I'm using for my simulation is causing more problems than the sun itself? If it does, then maybe I would have better success when the sun comes out and I can do some testing.