Indoor tabletop motion detector???

[Rhiannon Pendragon]

Does anyone sell an inexpensive indoor tabletop motion detector that controls
a lamp?

 

[Luhan Monat]

Does anyone sell an inexpensive indoor tabletop motion detector that controls
a lamp?

I've seen 'wall mount' for replacement of wall swithces. You need to
mount it in a box yourself.

 

[mike]

I've seen 'wall mount' for replacement of wall swithces. You need to
mount it in a box yourself.

There's a battery powered X10 device that can control anything you want.
mike

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[Watson A.Name - \Watt Sun, the Dark Remover\]

Does anyone sell an inexpensive indoor tabletop motion detector that
controls a lamp?

You just buy onw that installs in a wall switch box, and put it on the
table. You buy one of those blue electrical switch boxes for fifty
cents, and mount it in there. Run the wires out to the plug.

<Rant> I hate those things. At work, every time I'm in a room with
one, I'm under the desk hooking up the PC, or sitting there waiting, and
the damn motion sensor switch turns off. I gotta get up and wave the
hands or whateve to get it to go back on. And then a few mins later it
does it again! Grrrr.. >:-( </Rant>

 

[Michael A. Terrell]

You just buy onw that installs in a wall switch box, and put it on the
table. You buy one of those blue electrical switch boxes for fifty
cents, and mount it in there. Run the wires out to the plug.

<Rant> I hate those things. At work, every time I'm in a room with
one, I'm under the desk hooking up the PC, or sitting there waiting, and
the damn motion sensor switch turns off. I gotta get up and wave the
hands or whateve to get it to go back on. And then a few mins later it
does it again! Grrrr.. >:-( </Rant>

Build one of your LED flashlights with infrared LEDs and a
photocell to make it flash when the lights go out, then set it somewhere
aimed at the motion light.

 

[Rich Grise]

You just buy onw that installs in a wall switch box, and put it on the
table. You buy one of those blue electrical switch boxes for fifty
cents, and mount it in there. Run the wires out to the plug.

<Rant> I hate those things. At work, every time I'm in a room with
one, I'm under the desk hooking up the PC, or sitting there waiting, and
the damn motion sensor switch turns off. I gotta get up and wave the
hands or whateve to get it to go back on. And then a few mins later it
does it again! Grrrr.. >:-( </Rant>

I had a back porch motion detector light, and it was "smart" - if it
was switched on, then off, then on in something like a second, it would
latch on and ignore the sensor until the next time it was turned off
and then on.

I have no idea if that's a "standard" feature, but it'd be worth
checking it out if you find yourself stuck one of those things again.

Cheers!
Rich

 

[[email protected]]

Well, it's not that simple. The IR from the LED is short wavelength
IR, about 800 nanometers. The IR that the PIR motion sensor senses is
long wave IR, maybe 7000 to 15000 nanometers. So it's like pointing a
VHF transmitter at an AM radio and expecting it to receive something.
Ain't gonna happen.

However I could put a spark coil in place of the LED and light a gas
jet or something. That should do it. Probably burn the place down
too! :-o

 

[John Woodgate]

I read in sci.electronics.design that [email protected] wrote (in

Well, it's not that simple. The IR from the LED is short wavelength
IR, about 800 nanometers. The IR that the PIR motion sensor senses is
long wave IR, maybe 7000 to 15000 nanometers. So it's like pointing a
VHF transmitter at an AM radio and expecting it to receive something.
Ain't gonna happen.

However I could put a spark coil in place of the LED and light a gas
jet or something. That should do it. Probably burn the place down
too! :-o

Replace the LED with a resistor that gets warm?

(s.e.marketplace removed as irrelevant)

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

I read in sci.electronics.design that [email protected] wrote (in

Replace the LED with a resistor that gets warm?

Yeah, I thought about that, too. One problem here is that the PIR
circuits that I've seen have two things. One is a coupling capacitor
that's between stages. Another is the PIR sensor itself which has two
sensors and the output is the difference of the two. I guess that's to
prevent a parked car's warm hood from swamping the sensor and preventing
it from turning off. A resistor would be much like that, with no
apparent motion. So if you have a _moving_ warm body, it'll trigger the
sensor.

I'm not sure if lighting a small lamp in front of the sensor would do
the trick. If it was sensitive to that, the lamp that it turns on, once
on, would swamp the sensor and it would never turn off.

 

[Mark Zenier]

Well, it's not that simple. The IR from the LED is short wavelength
IR, about 800 nanometers. The IR that the PIR motion sensor senses is
long wave IR, maybe 7000 to 15000 nanometers. So it's like pointing a
VHF transmitter at an AM radio and expecting it to receive something.
Ain't gonna happen.

However I could put a spark coil in place of the LED and light a gas
jet or something. That should do it. Probably burn the place down
too! :-o

How about a nichrome based emitter set at 98.6 deg F, and a slow
moving fan between the heater and the lamp sensor.

Mark Zenier [email protected] Washington State resident

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

How about a nichrome based emitter set at 98.6 deg F, and a slow
moving fan between the heater and the lamp sensor.

I'm not sure what the fan is supposed to do. There are no convection
currents coming off a body that low a temp.

But you have a good point. Some of the motion sensors use ultrasonic
doppler to sense the motion. They have a transducer driven at a freq
controlled by a ceramic resonator. Any returning echoes are compared to
this reference, so movement is sensed, even if it's the air moving. And
it says in the sheet packed with the sensor that the sensor should be
installed at least 6 feet from any air duct. The contractor dorks who
installed them in our bldg installed the one in my room about 3 feet
from the air duct. And yeah, it would never turn off.

But these are not PIR motion sensors.

 

[John Woodgate]

I read in sci.electronics.design that "Watson A.Name - \"Watt Sun, the

I'm not sure what the fan is supposed to do. There are no convection
currents coming off a body that low a temp.

If there weren't, it wouldn't cool down. There is even a (very small)
amount of radiation, which is actually what the PIR is supposed to
detect!

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

I read in sci.electronics.design that "Watson A.Name - \"Watt Sun, the


If there weren't, it wouldn't cool down. There is even a (very small)
amount of radiation, which is actually what the PIR is supposed to
detect!

AFAIK, the PIR detectors don't detect the presence or absence of IR,
because they have a pair of sensors that only detect the difference
between the two, so if both change equally, there is no difference. If
they detected the absolute presence, then the first ray of sun coming in
the window and warming the wall would set it off forever.

Or at least 'til sunset. ;o)

 

[Mark Zenier]

I'm not sure what the fan is supposed to do. There are no convection
currents coming off a body that low a temp.

PIR sensors are AC coupled. They get their AC by the way the lens is
molded and the motion of the subject. They have a sensitivity pattern
that looks like a fingers of a splayed out hand, (or, I think, a two
element sensor with interleaved patterns, hooked up as a differential
sensor). But you can get the same effect with varying IR. There was a
project in Electronics Now for a long range PIR that used a motor driven
chopper with a single sensor.

Mark Zenier [email protected] Washington State resident

 

[Rhiannon Pendragon]

You just buy onw that installs in a wall switch box, and put it on the
table. You buy one of those blue electrical switch boxes for fifty
cents, and mount it in there. Run the wires out to the plug.

<Rant> I hate those things. At work, every time I'm in a room with
one, I'm under the desk hooking up the PC, or sitting there waiting, and
the damn motion sensor switch turns off. I gotta get up and wave the
hands or whateve to get it to go back on. And then a few mins later it
does it again! Grrrr.. >:-( </Rant>

I understand, but I just want this as a little light to come on when I
enter a dark area of the house, to light my way until I can get to a
switch.

You'd think some smart guys would have already come up with a little
tabletop box motion controller with an outlet for a lamp. They already have
almost everything else.

As far as the X-10 option, I'm not interested in having to buy a whole home
control system just to do this.

 

[Dave Platt]

You'd think some smart guys would have already come up with a little
tabletop box motion controller with an outlet for a lamp. They already have
almost everything else.

They do (or did) exist. I bought one at a surplus store a decade or
so ago which had a tabletop sensor, and a one-piece plug-and-outlet
dongle connected to the sensor via a 6' cord. It was just what you
want, I think.

Haven't seen one since.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

Watson A.Name - \"Watt Sun, the Dark Remover\"

PIR sensors are AC coupled. They get their AC by the way the lens is
molded and the motion of the subject. They have a sensitivity pattern
that looks like a fingers of a splayed out hand, (or, I think, a two
element sensor with interleaved patterns, hooked up as a differential
sensor). But you can get the same effect with varying IR. There was a
project in Electronics Now for a long range PIR that used a motor driven
chopper with a single sensor.

Ah, now I see what you want the fan to do. Modulate the Ir from the
emitter with the fan blades. That'll work only if the fan causes a
difference between the pair of PIR sensors. If the fan affects both
sensors equally then they would cancel out.

Another point is that the fan blade speed would have to be slow. The
PIR circuits that I've seen use an LM324 opamp with a cap between O
and -I so that it's a low pass filter. If the fan's IR flicker rate is
above maybe 5 to 10 Hz, it wouldn't get thru the LPF.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

"Watson A.Name - \"Watt Sun, the Dark Remover\""

wrote :


I understand, but I just want this as a little light to come on when I
enter a dark area of the house, to light my way until I can get to a
switch.

You'd think some smart guys would have already come up with a little
tabletop box motion controller with an outlet for a lamp. They already have
almost everything else.

I'm not sure why you're saying this. I did a google search for portable
motion sensor light and came up with 830,000 hits, among them this one:
http://www.safetycentral.com/safetycentral/baopmoacseli.html

 

[Mark Zenier]

I understand, but I just want this as a little light to come on when I
enter a dark area of the house, to light my way until I can get to a
switch.

You'd think some smart guys would have already come up with a little
tabletop box motion controller with an outlet for a lamp. They already have
almost everything else.

A quick look in a Home Trends catalog <http://www.shophometrends.com>
shows two types. One is a wall wart that plugs into a wall socket with
a controlled outlet, and another is a extension for a screw base light
bulb socket.

About 15 years ago, I just took the sensor head off a Heath brand
motion sensor dual floodlight fixture and put it on a table lamp.
The sensor head is self-contained.

Mark Zenier [email protected] Washington State resident

 

[Rhiannon Pendragon]

I'm not sure why you're saying this. I did a google search for portable
motion sensor light and came up with 830,000 hits, among them this one:
http://www.safetycentral.com/safetycentral/baopmoacseli.html

That's battery operated, I've been talking about a 120VAC desktop unit that
you could plug a lamp into.