Re: Deer camera for cars?

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Nick Hull" <nhull@xxxxxxxxxxxxxxx> wrote in message news:nhull-

 <stuff snipped>

> I probably need a sensor triggered by cars.

I'd go for an IR beam across the roadway about 3' up.  A car passing is
guaranteed to interrupt it.  It will be hard to keep them aligned without
setting posts into the ground.  Again, nose around Smarthome - they sell
sensors that look like PIRs as part of some of their remote driveway kits.

> > Show me where you have the detector set now, with C being where I would
> > place it - it should be close enough that car would fill the entire
> > field-of-view of the sensor.
> >
> > '_' = 10 feet
> >
> >                 C
> > _ _ _ _ _ _ _ _ _ _ _ _ _
> > Roadway
> > _ _ _ _ _ _ _ _ _ _ _ _ _
>
>
>    - - - - - - - - - - - -
>                            |  <- C
>    - - - - - - - - - -     |
>                       |    |
>
> Not good asci art but camera is aimed straight up the road from the
> outside of a curve, less than 10' from the road.  Maybe I should aim it
> more into the curve, with the road at the right edge of the field of
> view?

I would try to place the camera so that the bottom part of the car spends
the longest time possible in front of the sensor.  That's probably looking
at the rear of the car, unfortunately.  I would say the second best spot,
based on how my Hawkeyes detect cars, alongside the road, close by so that
all the exhaust parts pass by the detector.  Probably down at ground level
pointed up.  Another idea is to put it way down the road so that the PIR is
looking at the tailpipe of the car as it the car enters the zone have the
camera.  Or is the camera not separable from the PIR?

> > What's the ambient temperature at the sensor?  Is it possible the deer
> > trigger the unit only after multiple "counts?"  If that's the case, it's
> > going to be difficult to trigger on a car unless it stops to munch on
your
> > shrubs.   You might be able to tell by looking at the existing deer
pictures
> > to see if they are just entering the frame or already dead center when
the
> > camera trips.
>
> There is about a 5 second lag between trip and shoot, that's why I put
> it on a curve.  But it's not that I am getting an empty picture of the
> road after the car passed, the camera is not getting tripped and am
> getting no pictures.  I might have gotten one picture of an MT road when
> I drove by with my window down, I'll have to experiment more.  Ambient
> temp is chilly, that should help.  Turning on the headlights did not
> help.

All I can say at this point is that I know that X-10 Hawkeyes will track
cars with the usual X-10 hit or miss results at 50' and that it was not one,
but two that behaved that way.  IIRC, the X-10 PIRs are way too sensitive
for many applications and don't have any kind of pulse counter to delay
triggering and reduce falsing.

--
Bobby G.