In order to get a cheap and small infrared camera, I hacked a regular Webcam.
You can get the same Webcam from Amazon.com or ebay by less than $5.
This Webcam is really nice since the CCD can capture infrared light good at least good enough for our purpose.
Also This Webcam has six built in LEDs.
http://www.practicalarduino.com/projects/ps2-keyboard-or-mouse
Processing speed
PS2 mouse < Arduino < USB mouse
Hacking a mouse
It is interesting idea to hack a mouse to replace red LED to infrared LED.
(Japanese webpage)
http://www.ne.jp/asahi/air/variable/electronics/illuminant_ir_mouse/index.html
