Question About The Led Lighting On A Pir

[kenniewaters]

I am using a Pyronix KX15DT PIR.

When it detects motion it lights up a narrow strip of 'glass' on the front. (I know this feature can be disabled).

But the colour of the light changes!

Sometimes it's green, sometimes it's red/orange and mostly it's blue.

I can't figure out the significance of the colours.

The leaflet with the unit makes no mention of it.

What is going on? What do they indicate?

Ken

[antinode]

It is in the manual somewhere, but:

Green: PIR activation

Orange: Microwave activation

Blue: Both PIR and Microwave activated (alarm)

[kenniewaters]

It is in the manual somewhere, but:

Green: PIR activation

Orange: Microwave activation

Blue: Both PIR and Microwave activated (alarm)

Please can you clarify?

[There is no manual - just a single spec sheet in the PIR box. No mention of any colour lights or their meaning ]

What type of activity might cause Green or Orange and still not cause an alarm?

Ken

[james.wilson]

as its a DAUL tec it has 2 technologies. WHen both alarm then the sensor will alarm. If either one does then it wont.

PIR's are more sensitive to movement accross the zones, whereas as a microwave being a doppler shift device can only detect movement to and from it. Obviously the walls provide the reflections to allow the sensor to be quicker at detecting movement accross the detector

[kka]

Motion sensors detect based on two primary technologies:

1. Infrared where it looks for a heat pattern that moved from one "grid" to another. If you walk into the room, you'll notice how your movement activates the PIR. You should also notice that if you walk in and stand still, they PIR will ultimately return to a normal state. This is because you are no longer actively "moving" and it recognizes that that heat signature is stationary and to be expected. An intruder doesn't get beam into the protected area and suddenly materialize; they had to move into the protected area resulting in a change in IR energy across the grids.

2. Microwave is basically a radar gun looking for any movement of a mass in that area. All you need is a physical disruption of the microwave for it to trigger. Like the IR, a burglar has to physically enter an area as they don't magically appear. Also like the IR, if you were moving and stopped, the microwave would ultimately settle into a normal state because you physically stopped moving.

On DT's, they combine them both to eliminate false alarms. Since an intruder has to physically move in order to enter the area and they have an IR signature, the presence of both triggers the alarm.

[kenniewaters]

Thank you for those explanations. All is clear.

BTW - I went looking for the LEDs that produce all this light and could find none!

Then I found that there is a sort of plastic light diffuser that points to a small piece of electronics on the board.

This component looks like it generates point size light sources which are simply amplified by the plastic diffuser.

That sound right?

Ken.

[lawandorder]

Thank you for those explanations. All is clear.

BTW - I went looking for the LEDs that produce all this light and could find none!

Then I found that there is a sort of plastic light diffuser that points to a small piece of electronics on the board.

This component looks like it generates point size light sources which are simply amplified by the plastic diffuser.

That sound right?

Ken.

Yes that sounds about right. In days gone by discrete LEDs wer used but everything is surface mount nowdays and the diffuser you describe is a "light pipe", it works like a crude fibre optic cable and conducts light to the outer case.