how to fool a motion sensing lighting control

[dpetty]

I am in need of a circuit to "fool" a motion sensing lighting control. I have a motion sensing lighting control in my office which unfortunately is behind a bookshelf and so I have to get up every 20-30 minutes and trip it to turn my lights back on. Neither the shelf or the control is likely to be moved. There is no manual over-ride on the control unless you take off the cover and set a DIP switch which I don't want to do for several reasons.

The sensor is not triggered by LEDs or a small flashlight waving near by. Mirrors don't seem to reflect enough IR to get around the bookshelf. I have been able to "fool" the sensor with two 120V night light bulbs mounted about 6" apart and a manual switch to toggle back and forth between the bulbs to similate a moving IR source, but it's very cludgy and cumbersome and uses a lot of energy by itself.

Does anyone have any good ideas for fooling this sensor? Maybe a low power compact circuit or some other trick?

Thanks!


specs for the control are at:
**broken link removed**

 

[Sceadwian]

This hack isn't just ugly it goes against basic engineering, keep it stupid simple =) That being said the appropriate action is to have the sensor removed or bypassed by whomever takes care of the building where you work, it would be a good show of your persistence to find the right person to talk to get what you want done rather than rig a circuit for this. THAT being said =)

Did you use IR leds or regular LEDs? Because regular LEDS won't come even close to IR. IR leds MIGHT be close enough but it depends on the sensors actually response. Why don't you just blink a single night light bulb once every few seconds? There should be no reason to use two, the single pulsing should be recognized as moving. What I mean by that is you would use a simple timer circuit to turn the nightlight bulb on over 1 second every 5 minutes, that should easily keep the light from every going off. Why low power? Night light bulbs aren't exactly power hogs.

Try using a remote control, from ANY type of device. With the window of the IR remote pointed directly at the sensor window wait till the lights go out and without triggering it with your hand push a button with the remote, the pulsing from a close up IR remote will definitely set if off IF it's sensitive to that range. If that works then you have part of the solution, you just need a few IR LED's and low power timer with a switch, blink the LED's briefly every 5-10-15 minutes (whatever keeps the lights from going off) If you chose the proper timer you could probably use a smaller battery pack that would last months, if wall power is available the typical wasted current of a wallwart will likely be higher than the circuit itself.

So, provide some more information and I'd gladly help with it's design and construction.

 

[Externet]

Put a fan nearby the sensor ? Or a mirror to give it 'visual' field ?

 

[Sceadwian]

Externet. These sensors require motion, a signal that was there before that is not now and then comes back again repeated endlessly. Fans will not work the frequency is too high, they have lower limits on the motion sensing to avoid some animals peaking in and out or other false triggers. A mirror will only provide a static reflection.

 

[Mikebits]

I had this same problem in an office I worked in, I would have to do the hokey poky every time my lights would go out (Sure it was fun, but got old). I called maintenance and they fixed the problem. There are settings inside the sensor box you can change.

 

[Sceadwian]

While he didn't list the reasons...

There is no manual over-ride on the control unless you take off the cover and set a DIP switch which I don't want to do for several reasons.

Which is why he should do the same because you already had the folks in charge at your place do what you wanted =)

 

[Externet]

Seems dipswitch #5 enables manual-ON; but will shut-off automatically anyway :-(
Leave a pendulum clock nearby ?

 

[dpetty]

Thanks everyone for your comments, nudges and humor.

Sceadwian: 1) my daughter suggested moving a few books and cutting a hole in the back of the shelf - now that's KISS, but I'm an electronics guy, not a hole saw guy.
2) Regarding reasons: my "extra" bookcase is unauthorized and I don't want to lose it my making waves - I'm chair of the Environmental Committee and disabling the auto shutoff and risking the light being left on by housekeeping is politically unacceptable :>) 3) I'll try the IR LED route, I didn't really consider the wavelength of the LEDs I was testing with. Rather use LEDs so I can just mount a battery powered box on the back of the bookshelf rather than run a cord, use more power, draw more attention to my unauthorized bookshelf :>) 4) even with an incandescent bulb, blinking is not enough with this sensor. It appears to need IR "motion" which seems to be satisfied with two alternating lights. Part of my challenge has been trying to understand the sensor as demonstrated by failure of my early experiments (mirror to reflect my occasionally moving image, inanimate object waving or fluttering, LEDs weak or wrong wavelength, single incandescent bulb, etc.)

Externet: in manual mode the light stays on forever. We've actually resorted to this in some of our classrooms, but then folks forget to turn off the lights. The nicer sensors I've seen in other buildings allow the user to switch to manual mode from a switch on the front "panel". A pendulum clock with a live mouse attached would probably work, but then I'd have to change the mouse every few days.

I'll try the IR LED thing and get back to you all if I need any more help (or sarcasm :>) thanks!

 

[Sceadwian]

dpetty... Think about this for a second... You're going to create this elaborate device that will allow the lights to stay on, which in itself requires a switch to stay on... If you forget to turn the device off when you leave the room the lights are going to stay on anyways, EXACTLY the same as if you'd forgotten to turn the light switch off.. Disable the motion sensor and you've got the solution with the same effect without all the extra hubbub. Automatic lights don't make good environmental sense if the people in the rooms can't function! As far as being environmentally responsible consider the wasted time effort and energy that's already gone into this entire work around plan. I'm sorry but as a logical person I have to say that the current approach doesn't make any kind of sense to me.

 

[dpetty]

still can't trigger the motion sensor

I had a little time to work on this the other day, but haven't made any real progress. Now the challenge of actually making it work is getting to be more important than actually controlling the lights! I tried using two different remote controls to trigger the sensor, with no luck. Fortunately a light on the sensor blinks when it's been triggered so I can tell immediately. I also built up a circuit using a LM556 dual timer and a couple Radio Shack 276-0143 "High-Output 5mm Infrared LED" s, trying various LED currents, timing cycles, distances, spacing between the two LEDs etc, with no luck. I know the LEDs come on because I can see them when viewed thru my digital camera. There must be something about this sensor that "knows" the difference between a moving warm body and a moving or blinking IR LED.

 

[crutschow]

The sensor likely is sensitive to IR much longer in wavelength than the 0.9 micron a typical IR LED generates (they basically sense heat radiation, such as from a warm human body where the radiation peaks at around 10 microns wavelength) so it should be sensitive to an incandescent bulb operating at a low voltage (so the filament is just barely glowing). That would also significantly reduce the power consumption of the bulb. I suspect two such alternating bulbs would trigger the sensor or perhaps just one turning on and off.

 

[daradv]

Buy one of those dancing flowers that are powered by solar. I assume if you have motion lights in an office, you have florescent bulbs which will make the flower go back and forth. Place it in front of the motion detector while you're there and move once you leave. I have the same problem except our motion sensor is on the ceiling with no manual switch at all. I'm behind a cubicle so the lights turn off on me as well. I'm going to try the flower idea too.

 

[rthuey]

2010 thread revival but i'll throw in my .02 cents

oscillating heater. movement and heat.


wonder if OP came up with anything

 

[dpetty]

Thanks everyone for your ideas. I gave up on trying to figure out a compact, low-power circuit, although I think blinking two relatively small incandescent bulbs periodically would do the trick. I went with Sceadwian's suggestion to KISS. Fortunately my book case is actually a 2 shelf unit stacked on top of a 3 shelf unit. Using 12 ft of 2x4, I built an additional "shelf" to insert between the two units, and by leaving a gap in the books, the sensor can now see me at my desk. Haven't had any problems since. A few of my 'pod-mates' have had the facilities department replace their motion sensor with an on/off switch. Given the bureacracy, I think my solution saved time and money overall. three photos attached: how I used to have to wave at the sensor around the bookcase, the 2x4 rise, and the new view of the sensor through the gap between the books.

 

[Ross Craney]

I can't get my head around the "Chair of an Environmental Committee" is not allowed to have an extra bookcase.

 

[Mike odom]

The motion sensor has a lens on front of it that sets up 'fields', and the IR source has to move from one field to the next.

 

[Lolo]

I see you solved your problem but wanted to post this for people searching for solutions, as I was when I came across this post.
I was being driven mad by the motion sensor in the teacher work room at my school. There is a "privacy" wall in between the light switch/sensor and where teachers actually work...groan!! I could have asked for help from maintenance but it probably would never get taken care of or maybe someone would come 2 days before school is out and they wouldn't be able to change it because of some regulation. So I got my screwdriver out, removed the face plate and found the model number and brand of the switch. It took 30 seconds to find the installation instructions online. I changed the settings and voila, problem solved. I anonymously post-it-ed that the motion sensor had been disabled and put reminders on the door to turn off the light when you leave the room. Everyone is happier, no fancy devices required.