Hi Sami,

> I want to track a remote controled car attached to the computer.
> The car will be more than 10m away from the PC. Any ideas?

You will need to use some form of non contact transmitter in the
car and place receivers around the area and then triangulate
the position from the time of flight of the pulse or the incident
direction.

Options include Ultrasonic, Radio of InfraRed signals.

If you plan to build your own hardware and have limited
resources you are pretty much limited to Ultrasonic time
of flight of IR position. The radio Time of flight would
be the neatest idea but the only people that I have seen that
could do it on the small scale you want are at Lawrence
Livemore National Laborotories in the US and they are
not into helping little people.  Do a web search on
LLNL and MIR and you should find a very interesting
web page of theirs that has some neat stuff, including
some Radar range finders, intrusion detectors (I tried to
get some information from them on any people using it
but they could not say) as well as liquid level gagues
and some micro power radio receivers.  They also describe
a radio location system that would suit you but it has
not been implemented and the licencing fees are incredibly
high.

With US you place a Ping device on the CAR and then have
3 receivers and time the delay from the time the first
receiver gets the pulse and then add time to all 3 recived
times 0, a, b until circles of radius d, a+d, b+d at the
receiver locations meet at one  point then you have the
location.  Do this as required.

With IR you place a modulated IR beacon on the car and have
some CCD video cameras that have nice wide angle lenses
and IR filters to help them along and use a suitable frame
grabber system to receive the signals and then compare
the video frames at your beacon rate (say 15 Hz) and you should
be able to locate the vehicle.  With some smarts one camera
is sufficient if you have terrain knowledge or you have a
substantially overhead view.  Otherwise 2 cameras are
convenient as you just decompose the two inputs to bearings and
the position in 2D becomes simple.

Other methods will be harder.

If someone finds out about the LLNL MIR technology could they
let me or the list know the details.

Cheers
--
Kalle Pihlajasaari   kalle@ip.co.za   http://www.ip.co.za/ip
Interface Products   P O Box 15775, DOORNFONTEIN, 2028, South Africa
+ 27 (11) 402-7750   Fax: 402-7751    http://www.ip.co.za/people/kalle