http://www.free-track.net/english/Everything I learned I got from the site or by pming someone who had built one.
This thread from The Fugitive got me into it:
http://bbs.hitechcreations.com/smf/index.php/topic,223422.0.html_______________________
Cost: Webcam (Ebay) - $20
LEDs and resistors - $6-7
Battery: $4 for Lithium, $.85 for an Alkaline
Everything else was scavenged.
Items Used:
1 x Baseball cap
1 x Metal Coat Hanger
1 x Lithium 9v (you can use Alkaline)
1 x On/Off Dip Switch (from a hair dryer)
2 x 100 ohm 1/8 watt resistors
3 x 1.2v IR LEDs
2 x 30" of wire
Tape
Solder & Soldering Iron
Velcro
1 x Microsoft VX-1000 Webcam
1 x Floppy disk (used to replace the removed IR Filter on the Webcam - blocks out visible light) - see website for details on this
A 3 point cap setup. The frame is made out of the coat hanger. Used a little Solder to hold it together.
Lithium 9V power supply. A ON/OFF switch from a hair dryer. A resistors in-line on the positive cable.
Probably the weakest point of the design, the LEDs are held in place by a double sided tape and packing tape.
Microsoft VX-1000 Webcam mounted upside down on my desk, right about the monitor.