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Decent Motion Sensing Lights?
Above asks: "At my previous house I purchased a number of motion sensor lights to replace the standard flood lights. I simply went to the nearest Home Depot and bought a mid range model, and they worked great. Since then I've moved, and in the new house I did the same, and got some Heath-Zenith units from Home Depot. They were junk (came on all the time for no reason). I adjusted two different units to no end, they simply didn't work. Since that was basically all Home Depot carried, I went to Lowes, and got a Regent Lighting unit. It was better, but not by much. I want my back yard to be relatively sensitive, triggered by the dogs when we let them out, but the front yard to be insensitive, triggered only by a car or the close approach of a person. Where can I get a good quality, motion sensor flood light? What are the secrets to aiming and adjusting them so they work right?"
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Remember who paid for all those annoying pop-up and pop-under ads when they first came out? X10 are the primary reason all browsers come with popup blockers these days. Their internet marketing tactics stink.
I won't support them. And I urge others to do the same.
the growth in cynicism and rebellion has not been without cause
Most of the sensors have a plastic "light guide" in front of them that breaks the sensed area into zones. It is the changing difference between the zones that triggers the sensor. Try taking one of them apart and you'll see either variations in the lens plastic, or even a set of physical baffles between the outer filter and the sensor itself.
(You can actually walk by most IR sensors without setting them off if you move VERY slowly, which is why better quality alarm systems use radar or specific thermal level monitoring rather than just a change).
Which brings us to aiming. Most of the time the zones are arranged to be more sensitive to side-to-side motion than up/down. So if you have one oriented 90deg out of "true" then it'll be rather insensitive except in a narrow band. (This is a good way to limit the area of coverage of a sensor without having to break out the masking tape).
Speaking of which, the height and angle of the sensor makes a big difference for the same reason.
So I would recommend taking one apart, figuring out the zone layout and adjusting accordingly. (Heck, you can even just set one on a table and see what area it "sees" and how sensitive it is to motion in that area, then turn it 90deg and try again).
First off, I have to say I agree with the original poster... I too tried to use the Zenith stuff from Home Depot when replacing lights for a friend and the stuff simply doesn't work. Pretty disappointing since there isn't much to this stuff. When I started looking into doing lights for my home I also looked at the X10 stuff but finally decided to build my own infrastructure. Not that there is anything wrong with the X10 stuff... it's affordable, easy to use, and has lots of software support. However, I'm building some custom home automation stuff anyways (such as asterisk integration and a cross platform graphical data-flow language for microcontrollers so you can embed control logic onto a cheap controller board instead of using a dedicated pc without needing to know how to write code) so I figured I'd customize the motion stuff as well. I found some GE motion sensors for about $10 that work great (and actually come with docs covering sensetivity, range, effective angles, etc... which you don't normally get in a packaged unit). I modified them a bit to add tamper detection but otherwise they work great out of the box. These feed back into a controller board which can also control the flood lights (which are just standard floods controlled by relays). And yes, I'm sure all this can be done with X10, I just prefer to build my own stuff (http://www.kondra.com/circuit/circuit.html).
Please don't comment on stories in which you have no interest.
Most of the sensors have a plastic "light guide" in front of them that breaks the sensed area into zones.
Its not a light guide its a plastic fresnel lens with multiple elements which focuses light (actually heat) from various "zones" onto the sensor.
It is the changing difference between the zones that triggers the sensor.
Nope. The sensor is made from two seperate pyroelectric elements which are mounted side by side. It is differences between these two elements which triggers the device. This could be from the same zone or different zones. Sun light and other ambient light (heat) changes will affect both elements equally (you hope) so that they don't trigger the device.
Try taking one of them apart and you'll see either variations in the lens plastic, or even a set of physical baffles between the outer filter and the sensor itself.
(You can actually walk by most IR sensors without setting them off if you move VERY slowly, which is why better quality alarm systems use radar or specific thermal level monitoring rather than just a change).
Which brings us to aiming. Most of the time the zones are arranged to be more sensitive to side-to-side motion than up/down.
The are all like this due to them being two element devices.
So if you have one oriented 90deg out of "true" then it'll be rather insensitive except in a narrow band. (This is a good way to limit the area of coverage of a sensor without having to break out the masking tape).
True.
Speaking of which, the height and angle of the sensor makes a big difference for the same reason.
So I would recommend taking one apart, figuring out the zone layout and adjusting accordingly. (Heck, you can even just set one on a table and see what area it "sees" and how sensitive it is to motion in that area, then turn it 90deg and try again).
The biggest difference between the systems you can buy is the shape of the fresnel lens. You can have just one main zone or lots of sub zones or a combination of both. Most good systems will give you a diagram of the size and position of the zones which you can use to choose and position them.
wot no sig
I ended up giving up on backyard astronomy because I kept trigger neigbors' security lights. Nothing like spending half an hour getting dark adapted and being hit in the face with a pair of 150 watt spot lights.
One of my neighbors has a burglar alarm which he only sets when he goes on vacation. It has internal motion sensors that are triggered if a passing wind rattles one of his windows. This means we are treated to a 120db external siren on almost a daily basis.
Blackouts are an inconvenience, but we used to make them fun by lighting a fire in the fireplace, cooking over a camp stove, and lighthing candles and lanterns and maybe reading stories to the kids. But a couple of years a go a vogue went around the neighborhood for buying gasoline powered emergency generators. Since noise from these things apparently isn't regulated, lamplight reading is out because the neighborhood sounds like a motor speedway.
I'm all for collecting geeky stuff, but it's one thing to have an attic electronics lab, it's another to deny a neighbor the right to be in his back yard in the dark. There's a growing and unhealthy obsession with extending and expanding our personal space, whether it's building houses as close to the property line as allowed, shining lights into neighbors' yards and windows, or driving an absurdly large SUV.
The Stoic philosophers reasoned this way about happiness: if happiness is having all your wnats satisfied, the surest way to happiness is to self-regulate your wants. Epictetus once told the story of placing an iron lamp on the outside of his house; he heard an odd noise outside his door he went out to find that a thief had stolen the lamp. "Tommorow, my friend," said Epictetus, "you will find a clay lamp; a man can only lose what he has."
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
I had the same issues Home Depot & Lowes both stock crap. Go to an electrical supply house and get RAB lights. They simply work. http://www.rabweb.com/product_line_detail.php?prod line=STL360
I'm extremely please with the results.
I'm not associated with RAB, etc.
Steve
Regards, Steve