From Unknown PIR to Dual TEC

[GalaxyGuy]

4 minutes ago, RayPooley said:

Thanks again although it's probably the brick I need to detect more so than the glass. What do you think?

 

Detection of a flying brick with a standard PIR, although possible, will not be 100% reliable. PIR's work by detecting differences in heat across planes and zones. Since the brick has no heat, you are relying on it changing the thermal pattern of the room. If the brick is far from the sensor, then it will have less impact on the pattern.  You could always employ all three types of detection as a belt and braces approach.

[RayPooley]

10 minutes ago, MrHappy said:

 

I'm saying you failed to select a competent service provider  

I don't make a habit of interviewing service providers. I don't have the time. I tend to take them at their word or, at least, the words on their advertising.

[RayPooley]

1 minute ago, GalaxyGuy said:

 

Detection of a flying brick with a standard PIR, although possible, will not be 100% reliable. PIR's work by detecting differences in heat across planes and zones. Since the brick has no heat, you are relying on it changing the thermal pattern of the room. If the brick is far from the sensor, then it will have less impact on the pattern.  You could always employ all three types of detection as a belt and braces approach.

Here's the thing. A basic PIR only detects infra read heat. Right? In particular infra red radiation that is above that of the surrounding environment. Furthermore, having tested mine, they only trigger when that "hot spot" is moving. They are basically motion sensors. The same as the technology I have in the toilets that turn the lights on when someone walks in.  And loose bricks tend to be at ambient temperature. So I wouldn't expect a basic PIR to detect a flying brick unless the brick had been basking in the sun so that it was significantly hotter than the space around it. But that's a bit hit and miss. So I am looking for something that doesn't rely on infra red radiation. That's why I have gone for the Dual TEC infra red and microwave technology. 

[james.wilson]

No movement detector will detect a 'flying brick' 

A dualtec needs both technologys to activate not just the mic etc.

If you had a sensor that sensitive it would be going off all the time. That's fine when all its doing is turning a light on, not so much for an intruder alarm.

You need to protect the perimeter as above ie glass break (I hate them) vibration (not advisable on a front high street window, or foil.

 

Id also politely suggest you don't keep saying 'this is simple / plug and play etc' when talking to the people you want advice from and know more than you or you wouldn't be asking.

[MrHappy]

 

1 minute ago, RayPooley said:

Here's the thing. A basic PIR only detects infra read heat. Right? In particular infra red radiation that is above that of the surrounding environment. Furthermore, having tested mine, they only trigger when that "hot spot" is moving. They are basically motion sensors. The same as the technology I have in the toilets that turn the lights on when someone walks in.  And loose bricks tend to be at ambient temperature. So I wouldn't expect a basic PIR to detect a flying brick unless the brick had been basking in the sun so that it was significantly hotter than the space around it. But that's a bit hit and miss. So I am looking for something that doesn't rely on infra red radiation. That's why I have gone for the Dual TEC infra red and microwave technology. 

 

alarm movement detectors are to detect the infra energy of an intruder (ideally human sized moving across a room) they may see flying bricks, house plants falling over, blinds moving but is not really their purpose.

 

A breakglass detector should detect the sound of breaking glass depending on its positioning & type of glass in the pane.

 

They also may detector other sounds like key being jangled or bottles being broken on the street

 

If you want to protect glass buy a shutter 

[RayPooley]

8 minutes ago, james.wilson said:

No movement detector will detect a 'flying brick' 

A dualtec needs both technologys to activate not just the mic etc.

If you had a sensor that sensitive it would be going off all the time. That's fine when all its doing is turning a light on, not so much for an intruder alarm.

You need to protect the perimeter as above ie glass break (I hate them) vibration (not advisable on a front high street window, or foil.

 

Id also politely suggest you don't keep saying 'this is simple / plug and play etc' when talking to the people you want advice from and know more than you or you wouldn't be asking.

Just telling it like it is. You are wiring things together. 

[james.wilson]

excellent, crack on then

[RayPooley]

7 minutes ago, MrHappy said:

 

 

alarm movement detectors are to detect the infra energy of an intruder (ideally human sized moving across a room) they may see flying bricks, house plants falling over, blinds moving but is not really their purpose.

 

A breakglass detector should detect the sound of breaking glass depending on its positioning & type of glass in the pane.

 

They also may detector other sounds like key being jangled or bottles being broken on the street

 

If you want to protect glass buy a shutter 

The local council wouldn't allow shutters on all of the windows. Only the large ones and even then they insisted as a condition of the planning permission that the shutters must be fitted on the INSIDE of the windows. You think I'm kidding don't you? I'm not.  

3 minutes ago, james.wilson said:

excellent, crack on then

Will do. Thanks for your help.

[MrHappy]

Just now, RayPooley said:

The local council wouldn't allow shutters on all of the windows. Only the large ones and even then they insisted as a condition of the planning permission that the shutters must be fitted on the INSIDE of the windows. You think I'm kidding don't you? I'm not.  

 

In addition to being an alarm monkey I was once a shutter monkey....

 

I could have been a c# monkey, but I had more self respect ...

[al-yeti]

43 minutes ago, RayPooley said:

I don't intend to. I can't afford to pay for a force field around the building and NASA won't let me have one for free. So the next best thing is to detect the brick as it enters air space and is flying through the air as it enters the window. It seems reasonable to me that any cold flying objects inside the building during closing hours have come from outside so it's something one should be aware of as soon as possible.

Ok but if you don't want perimeter protection by the way of shocks etc how will be youbdetect a brick before it breaks your windows 

 

Shutter would be good , with the necessary detectors on it 

 

Easy init