Re: PIR Options

["psghome2002" <psghome@xxxxxxx>]

I trialled a few different PIR's for the same use (there's been a 
lot of discussion about this on here before). I wanted the 'perfect 
PIR' that had to meet the following criteria:

1) Quick triggering
2) Stable so as not to give false alarms when used as security PIR
3) Looks good
4) Ability to turn On/Off LED
5) Interchangeable Lens for wide/curtain mode detection.

Point 1 is normally part dealt with by user selectable 'pulse count' 
i.e. how many detection pattern 'beams' need to be broken to trigger 
and the internal logic used by the detector (and how quick it is). 
Generally it is best to go for a sensor that allows a pulse count of 
between 1 and 4, although most will start at 2 for stability (low 
false-alarm) reasons.

I must say that I have still not found the ideal sensor - I have a 
combination of:

Alarmcom IR120C - look really good, use great 'black mirror' 
technology (cutting down susceptibility to sunlight and other 
unwanted radiation) and are very stable but a little slow to trigger 
+ they are fairly cheap trade.

Pyronix Magnum Ultra - (existing PIR's in my house) - OKish looking, 
seem quite stable and have selectable 1/2/3 pulse count making it a 
bit quicker to trigger when on 1.

Optex RX-40QZ - Recommended by Comfort but I've not tried this yet - 
only 2/4 pulse count and detection area doesn't look very dense.

I think the detection area density is also important. This is the 
pattern of 'detection beams' that spread out from the sensor and how 
closely they are spaced. The lower the density, the further you will 
have to move to trigger the sensor (depending on pulse count). This 
is especially important if you want to detect occupancy in, say, the 
living room where you may sit on a sofa for longish periods of time. 
A high-density pattern and propper alignment of the PIR will help 
here although you cannot guarantee that the sensor will pick up 
small movements.

Someone mentioned a dual tech sensor on here a while ago. Generally 
these are no good as their trigger time is pretty poor (long). They 
use a combination of IR detection and microwaves. This particular 
sensor gave separate outputs for both sensors, allowing the 
(quicker) microwave technology to be used on it's own. The microwave 
bit can be difficult as it will apparently sense through walls 
(although I've not tried one) - so siteing is important. Anyone use 
these - I'd love to hear if it's successful.

Paul.

--- In ukha_d@y..., "Amar Nagi" <amar@a...> wrote:
> 
> I have homeseer, ocelot and I want to set up sensors around my 
flat to
> indicate when a room is occupied. What are my options ? I get a
bit
> confused
> by the range of different sensors (Pir) 
> 
> Any recommend anything ? I don't really want to go for the RF x10 
route
> 
> Ps sorry I used the wrong subject line b4.

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