PIR Sensor that can 'see through walls' legal?

[333rocky333]

You say it was fitted recently, see if the council can give you details of the sensor they use as its likely to be used throughout the borough, then google it or post back here with details, they may be even able to put you on to there contractors, round here they use Morrisons, they will send an engineer with Id and they will assist you.

 

[AnnaBee]

Well Annabee its got me puzzled.
I think I can say with certainty that an infrared sensor cannot see through walls.
Yes microvave can penetrate possibly a timber door but hardly a concrete wall and then pick up your movement on the other side. Microwave is akin to Radar. Although I have been around to long to rule anything out, but I would warn you to expect, scepticism if you go to the council.

It does seem to only see me once I reach the point in the hallway where it could be seeing me through the door. Looking through it diagonally though as I don't need to be right in front of it.

http://img31.imageshack.us/img31/113/29472688.png

 

[ianblue]

The level of microwave that a sensor of that type sends out would not be harmful

 

[RF Lighting]

I've fitted plenty of microwave lighting detectors and never had any that can see through walls.

I've also got dual tech detectors on my burglar alarm, and neither the PIR or the microwave detection is triggered through glass or stud work walls.

 

[OwainDIYer]

it might be a microwave detector, which can sometimes be activated through walls (more likely through the wooden door). They may be specified for local authority contacts because the sensor can be concealed making them less vulnerable to vandalism than a PIR

http://www.elkay.co.uk/product.asp?id=52&catid=1[/QUOTE]
That was my thought when the symptoms were described. Doubt it would work through a wall (except a thin stud wall), but I wouldn't be at all surprised if it worked through a wooden door.

If the council won't fix it, then time to line the door with aluminium foil or paint it with nickel based (conductive) paint I think.

So would that not react to the broom being waved around (see post above this one)? That is horrible, I hate the council. Talk about big brother. If that is the problem can they 'turn it down' make it less sensitive?

Depending on the detector it might be adjustable for range or sensitivity. It would react (a bit like radar) to large objects moving but not ones that create a small disturbance like a broom.

However, the only people who will know the light is coming on is anyone who happens to be looking out of their spyhole at that moment and seens the light comes on - and they'll probably think "oh, the light comes on on its own". They're extremely unlikely to connect it to your bathroom habits.

It might be wise to ask the Council" what type/model of movement or other sensors are fitted to the lights at xxxxx" without saying why, then they have no excuse to be obstructive. Not that councils need excuse, but don't give then one.

 

[Mrdjc]

I think it's time to bust out the camera and take some pictures of your hallway and the common area and the device..

Annabee, this is a public forum so dont post too much information, the light or sensor is all were concerned in

Right, because we are all serial killers slash rapists who will know EXACTLY which building it will be and which apartment, because of three pictures:

1. The hallway facing towards the door with the wall between the hall and the common area.

2. The wall between the hall and the common area taken from the common area.

3. The device that supposedly triggers.



Reason I asked for pictures, there is probably something everyone is overlooking, but has not been mentioned.

 

[bernardgreen]

Micro-wave sensors can sense motion behind a wooden door or a plaster board stud wall close to them if they are high power devices.

I think one can dismiss IR motion sensing in this case. It is possible for a heat source behind a breeze block wall to be detected by a sophisticated PIR sensor but that type of sensor is not going to be used in a communnal stairway lighting scheme. Far too expensive.

It certainly is worth mentioning this to the council and if it is a microwave effect then they can reduce the emmittted power which will prolong the life of their sensor.

The micro-wave power emmitted from the sensor is not a health risk.

That said it might be that the council are intentionally using high sensitive micro-wave devices to specifically turn on the lights as tenants move to open their front door so callers can be seen before the door is open. A caller with dubious intent could stand motionless until the lights time out before ringing the door bell.

Personally I would see the effect as a beneficial effect.

 

[viewer]

From your drawing it looks like there is another flat opposite. Do they have the same effect. You'd have to agree movements and use your camera to check.

 

[AnnaBee]

it might be a microwave detector, which can sometimes be activated through walls (more likely through the wooden door). They may be specified for local authority contacts because the sensor can be concealed making them less vulnerable to vandalism than a PIR

http://www.elkay.co.uk/product.asp?id=52&catid=1[/QUOTE]
That was my thought when the symptoms were described. Doubt it would work through a wall (except a thin stud wall), but I wouldn't be at all surprised if it worked through a wooden door.

If the council won't fix it, then time to line the door with aluminium foil or paint it with nickel based (conductive) paint I think.

So would that not react to the broom being waved around (see post above this one)? That is horrible, I hate the council. Talk about big brother. If that is the problem can they 'turn it down' make it less sensitive?

Depending on the detector it might be adjustable for range or sensitivity. It would react (a bit like radar) to large objects moving but not ones that create a small disturbance like a broom.

However, the only people who will know the light is coming on is anyone who happens to be looking out of their spyhole at that moment and seens the light comes on - and they'll probably think "oh, the light comes on on its own". They're extremely unlikely to connect it to your bathroom habits.

It might be wise to ask the Council" what type/model of movement or other sensors are fitted to the lights at xxxxx" without saying why, then they have no excuse to be obstructive. Not that councils need excuse, but don't give then one.

Micro-wave sensors can sense motion behind a wooden door or a plaster board stud wall close to them if they are high power devices.

I think one can dismiss IR motion sensing in this case. It is possible for a heat source behind a breeze block wall to be detected by a sophisticated PIR sensor but that type of sensor is not going to be used in a communnal stairway lighting scheme. Far too expensive.

It certainly is worth mentioning this to the council and if it is a microwave effect then they can reduce the emmittted power which will prolong the life of their sensor.

The micro-wave power emmitted from the sensor is not a health risk.

That said it might be that the council are intentionally using high sensitive micro-wave devices to specifically turn on the lights as tenants move to open their front door so callers can be seen before the door is open. A caller with dubious intent could stand motionless until the lights time out before ringing the door bell.

Personally I would see the effect as a beneficial effect.

Thanks guys what you have written is extremely helpful. So it would seem it is either microwave or voodoo. At least I understand why it is happening now. I'm going to speak to them and see if they will turn it down (the sensitivity on the sensor).

To everyone who has taken the time to riddle this out for me thank you very much I really appreciate your kindness and expertise.

 

[ban-all-sheds]

Please let us know what happens - what the problem turns out to be, and what they do about it.

 

[RedHerring2]

So it would seem it is either microwave or voodoo.

Nice to see someone maintaining their sense of humour too.

 

[OwainDIYer]

That said it might be that the council are intentionally using high sensitive micro-wave devices to specifically turn on the lights as tenants move to open their front door so callers can be seen before the door is open. A caller with dubious intent could stand motionless until the lights time out before ringing the door bell.

Personally I would see the effect as a beneficial effect.

I'm not sure a council would be that clued up, but I would agree about the usefulness of the effect.

Some door entry systems have a button on the flat phones to turn the close lights on from inside the flat, for the same reason.

 

[misterhelpful]

Pressure sensor under your floor that turns light on as you approach the front door and lights the communal area in case you are going out?

I know, I know, highly unlikely but there must be an answer somewhere!

 

[Alarm]

I go with Bernard. Microwave turned up a bit high. A PIR will not do this.

Will we get a picture or any further replies ?

 

[kirkgas]

maybe there is a cat sleeping in the communal area and when you walk through the hall you wake it up and it moves and sets the light off,