I had access to all the things I needed - squirrels, tools, wood, web server, ... I looked around the web for design ideas, then set up the following.
And, it only took me two years to get around to publishing this entry. Hope you like it.
Step 1: Design
I went with USB as it was cheap, simple, and quick. The biggest limitation is range. USB-2 has a range of 5 meters. I consider this build a "proof of concept". See future improvements section for alternate camera ideas. You can overcome the 5 meter USB limit with active USB cables or addition of a hub. ( or go with a non usb camera - a wifi enabled camera would be ideal )
Actual house dimensions are pretty flexible as well. My target for the house area was roughly 1'x1' and 18" tall. I used 11.5" pine shelving, and only cut pieces to length.
Tools used - I used all my power and air tools - table saw, nail gun, etc - but this build could easily be done with a hand saw, glue, screws, a drill, and a screwdriver.
Materials - wood $20, lexan $5, camera $15, software $30, screws and stuff were whatever I had around.
see additional information is in image notes in yellow boxes on the pictures.
Step 2: Software
Configurable motion detection and capture
Options for alerting
Archiving and automatic file management
Built in streaming of live video
The web cam software runs on a pc and pushes captured images to the web server over the network. Streaming video requires a live connection to the capture PC.
The web server is an old pc running iis, with some custom aspx scripts for thumbnail generation and image archiving.
Step 3: Deployment
Last year the mom squirrel built a nest in the box so it was pretty difficult to see the babies. She kept them covered. It seemed to be temperature dependent, and the spring was quite cold, so it limited viewing opportunities.
I believe there were three baby squirrels. They moved out around the third week of April. It was quite sudden. They were there one day, and no sign of them after that.
Step 4: Improvements
1) It would be good to have better camera( resolution) and lens( focus) for higher resolution wide angle view with expanded depth of field. Most ccd cameras will work in IR spectrum, though some have IR filters that will need to be removed. ( point your remote control at your favorite digital camera... you will probably see the flashing light )
I considered cameras with pan and zoom, but figure the noise would disturb the occupants.
2) Internet connection that can support the opening up images and video feed beyond F&F.
3) second camera, outside the house, for real color shots during the day.
4) microphone for audio