The LED tracking ball is a very
good alternative to conventional tracking balls and is pretty easy to make.
Start off by cutting the top
of a ping-pong ball ("bad quality" ping-pong balls are better,
the plastic is more rigid)
Get a fluoro red spray can
and paint it - It's better to work in layers leaving a few minutes for each
one to dry
Get a needle and burn it with
a lighter for a few seconds, then make the holes on the back to fit the
switch and the LED on the front
Be careful soldering the wire
to the switch so you don't burn the ping-pong ball
Add some silicone in there
leaving a gap to fit the battery
The idea was to make a tracking
marker where you would have 2 options
If it is a wide shot you can
track the whole ball (like conventional markers)
In a medium or close shot though,
you can track the green LED having the fluoro red in the background which
makes it easier for the tracking software to work out the contrast provided.
Another advantage is that you can
use it at night or with poorly lit scenes. The LED still illuminates an area
of 1-2cm around it.
