RF Tracking, Interference?

[jeffroot]

Im looking into using RF technology to perform 3d spatial tracking and feedback. Has anyone come across a product/prototype that uses this technology as a scaled down GPS system? If so, would the RF sensors measure range by counting wavelengths? I've been able to find only one product that mentions RF technology as a spatial tracking device, a digital pen -

http://www.itpen.com

It is ambiguous as to how it uses RF to track the motion.

Also, I have been told that RF sensors and transmitters are resistant to electronic noise. Would anyone be able to tell me in practice or in theory if RF sensors and signals would be affected by an arc welding field?

 

[VEBill]

"I have been told that RF sensors and transmitters are resistant to electronic noise."

In general, that is not correct. It might be correct in specific instances where such a requirement is included in the design, but not in general. Especially arc welders at close range.

As a guess, I suspect that the 'itpen' contains a little sharp pulse generator (some might call it UWB). The pulse is perhaps detected by a couple of receivers to determine the 2-D location. Maybe the signal is modulated with some pressure data.

Tracking inside a 0.25mm space is quite a claim, as opposed to tracking to within 0.25mm.

One needs to be skeptical because start-up companies often stretch the truth a bit. It might be worth looking on

http://www.uspto.gov

to see what they're really invented. Look-up the assignee name, inventor name (based on names in their corporate profile), etc.

 

[IRstuff]

You missed the part about the "nonvisible sensors embedded in a complimentary clipboard" Itpen is essentially a digitizing tablet and probably has no direct application to a larger scale environment without serious development money and effort.

You really need to describe exactly what you want to do and not prejudice the outcome by posing hypothetical solutions without stipulating the exact requirements.

TTFN

FAQ731-376

 

[036634732]

no think goog found

 

[gszczesz]

Jeff,

Pulse timing is an old technology dating back to the 70's. Since you detect the edge of a pulse, any electro-magnetic noise (like power lines) can create a false edge. This technology is used mainly in animatronics, etc...

Modern technology could use modulated RF signals so that any other electro-magnetic noise can be filtered out. Instead of a pulse, you would use phase-delay information. This is more robust to noise, but ofcourse requires more advanced circuitry. I'm surprised too that this technology hasn't come around mroe, but the main probablem is probably a chicken-and-egg issue: a market. Creating such a chipset would be a large investment, but there's no established market that could justify the cost.

Well, not until the Wii came along. But even the Wii uses an accelerometer, which they found good enough for most games. Positioning and orientation tracking would be better, but most games don't require it.... yet.