bluetooth proximity

AVee openmoko-comunity at
Mon Jun 16 16:59:20 CEST 2008

On Monday 16 June 2008 14:40, David Kepplinger wrote:
> Hi,
> I don't think that's feasible. To measure (with 2 devices) you need
> two very synchronous clocks and a very exact measurement. Because the
> signal travels with approximately the speed of light (about 300.000
> km/s), an error of 1µs is an error of 300m. There are a lot of reasons
> why this is not feasible. Sorry.

I tend to agree, however, things might change if you add gps. You'd might just 
transmit your own speed and location, although you will probably hate the 
precision of that without DGPS (which may never work on the Freerunner) and 
if may not work al that well indoors. 
But GPS could also solve the first problem you mentioned, it can provide the 
same clock to the two device. That leaves only the 'exact measurement' to be 

It might work, but the precision will probably still be far to low to be 
useable for anything.


Everything should be made as simple as possible, but not simpler.
  -- Albert Einstein

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