Re: Cheap and small Break Beam circuit ?

["Frank Mc Alinden" <frankmc@xxxxxxxxxxxxxxxx>]

Hi Marcus

If the break beams involve  having the tx and rx on opposite sides of the
door then maybe consider this little ultrasonic device........not as cheap
as a beam break but  onlt required on side of the door plus a serial
interface.......
http://www.maxbotix.com/

Gerry Duprey is currently developing a pic micro interface which will
handle
up to 12 of these and will do an xPL Plugin for it...........Im going to
use
2 of these to monitor my pond water level and also a water tank (when i get
one)..
HTH
Frank


----- Original Message -----
From: "Marcus Warrington" <marcus.warrington@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Wednesday, July 12, 2006 11:37 PM
Subject: [ukha_d] Cheap and small Break Beam circuit ?


> Having now got all the lights (except the kitchen/Utility) on X10
> circuits I've now started to think about how to implement occupancy
> detection. Originally I was going to use ceiling mounted 360 degree
PIRs
> but having trailed them I find that they're sensitivity isn't up to
> detecting someone walk into a space in time to get the light on (not
> helped by the X10 comms latency). The only way I can get anywhere near
> is to mount them directly over the entranceway since they appear to be
> more sensitive directly underneath the sensor. So, next thought was to
> mount them centrally in the room but then use a break beam across the
> entranceway (door jam) as a primary trigger. So does anyone know a
small
> simple break beam device or circuit that I could install across a
> doorway. Needs to be small and sit relatively flush with the surface
> (the door jams are wood so I can rebate a little bit) and be easily
> connected to HomeVision.
>
> Marcus
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>