Indoor tabletop motion detector???

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

--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
 Click to see the full signature
Reply to
Luhan Monat
Loading thread data ...

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

Reply to
Rhiannon Pendragon

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

--
Return address is VALID but some sites block emails
with links.  Delete this sig when replying.
 Click to see the full signature
Reply to
mike

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.

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.. >:-(

Reply to
Watson A.Name - "Watt Sun, th

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

Reply to
alondra101

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.

--
Former professional electron wrangler.

Michael A. Terrell
 Click to see the full signature
Reply to
Michael A. Terrell

a

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.

Reply to
Watson A.Name - "Watt Sun, th

I read in sci.electronics.design that snipped-for-privacy@hotmail.com wrote (in ) about 'Indoor tabletop motion detector???', on Fri, 1 Apr 2005:

Replace the LED with a resistor that gets warm?

(s.e.marketplace removed as irrelevant)

--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
 Click to see the full signature
Reply to
John Woodgate

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 snipped-for-privacy@eskimo.com Washington State resident

Reply to
Mark Zenier

a

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.

Reply to
Watson A.Name - "Watt Sun, th

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)

Reply to
Watson A.Name - "Watt Sun, th

I read in sci.electronics.design that "Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote (in ) about 'Indoor tabletop motion detector???', on Sun, 3 Apr 2005:

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!

--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
 Click to see the full signature
Reply to
John Woodgate

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 snipped-for-privacy@eskimo.com Washington State resident

Reply to
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.

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

Reply to
Rhiannon Pendragon

wavelength

is

pointing

something.

a

driven

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.

Reply to
Watson A.Name - "Watt Sun, th

that

the

and

the

it

have

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:

formatting link

home

Reply to
Watson A.Name - "Watt Sun, th

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.

--
Dave Platt                                    AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
 Click to see the full signature
Reply to
Dave Platt

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

Reply to
Rhiannon Pendragon

A quick look in a Home Trends catalog 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 snipped-for-privacy@eskimo.com Washington State resident

Reply to
Mark Zenier

Buy a replacement motion sensor and mount it on a plastic electrical box then use a romex coupling to hold the wires. Cut an extension cord in half to add a power cord and outlet. How hard can it be?

--
Former professional electron wrangler.

Michael A. Terrell
 Click to see the full signature
Reply to
Michael A. Terrell

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.