On 28/10/2010 13:28, Olin Lathrop wrote:
> Oli Glaser wrote:
>> I haven't been following this thread too well (so ignore this if it's
>> already been ruled out for some reason), but from what I have seen I
>> can't help thinking something like the "clickety click" detector
>> (Ithink) Joe suggested would be the simplest way of doing this,
>> hardware and software wise. If you can place a cheap mic (preferably
>> with a filter) reasonably near the joins in the track then it should
>> be no problem. and pretty accurate - I imagine the mic would not even
>> have to be very near as long as it was directional.
> This has two main problems:
>
> 1 - There will be a great deal of noise on the clicks.  Our human brains =
are
> very good at extracting such patterns from noise, but electronics or DSP
> algorithms may not be so easy or effective.

Possibly, but I don't think it would be that difficult to do. It depends=20
on the setup/situation.

> 2 - You still rely on knowing parameters of the train, which in this case=
 is
> the spacing between wheels.
>

Of course, but I thought that part was rther obvious.. :-)
Note the "something like" in my post - it depends a lot on what=20
information is available, and the situation (which I am mostly in the=20
dark about)
For instance, if all trains are a standard length, then it could be as=20
simple as timing the duration of the noise.
Sensing the wheels would probably work okay too, plenty of ways to do this.=
..



--=20
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