"Neil Williams" wrote in message
...
Mark Brader wrote:

Well, which is supposed to break the beam -- your body or your extended
hand? Where are the lamp and sensor placed in relation to the door?

The sensor is above the door. I suspect it's ultrasonic or passive
infra-red rather than a reflected beam, as there's nothing I can see for
it
to reflect off.

I'm not sure what the intention is - but the design seems to be a poor
one.

Isn't it so the doors open only when someone wants to use them rather than
every time anyone moves in the vacinity? If not, they seem to do that job
quite well by happy coincidence.

Shane