Hi, is there a way an IR motion sensor could act like break beam sensor up to distance of 2 meters?
i don't see why not. if your target plate is 2m away, trigger an event when the device reports any distance less than that.
The IR sensor can be fitted with shutters to shield out all but what is in front.
Weedpharma
weedpharma:
The IR sensor can be fitted with shutters to shield out all but what is in front.Weedpharma
Are these shutters commercially available? I tried to cover the PIR with insulating tape which seemed to do the trick but the greater the distance the bigger the angle of view. Clearly there's some room to improvement.
Fit a piece of tubing to the font of the sensor and cover all around it.
The longer the tube and the smaller the diameter, the narrower the beam.
Test example setup: Place a small carton over the sensor - cut a hole in it for the tube.
luckyx182:
Are these shutters commercially available? I tried to cover the PIR with insulating tape which seemed to do the trick but the greater the distance the bigger the angle of view. Clearly there's some room to improvement.
That makes no sense. The angle cannot change, once established. The area of view is a function of how far it is away from the sensor.
IR is light. Review optics. Stopping down the angle of view will also reduce the amount of IR light seen by the sensor. You may have to increase the intensity of the IR light source.
Paul
How to shrink field of view of IR sensor:
Select IR sensor has small angular response (SD5410):
SD5410 12 degree
SD3410 90 degree
OP refers to IR motion sensor. This suggests burglar alarm style.
Adding something to block the lens from receiving from the sides would seem suitable.
Cover part of the lens or put it in a tube.
Weedpharma
Further to my post #4, u can also remove the freznel lens (which is what I am doing) and place the tube directly around the PIR sensor head.
Paul_KD7HB:
That makes no sense. The angle cannot change, once established. The area of view is a function of how far it is away from the sensor.
Paul
Now I spotted what I wrote. 
You are right, the angle cannot change, what I meant was the area of detection.
sonnyyu:
How to shrink field of view of IR sensor:Select IR sensor has small angular response (SD5410):
SD5410 12 degree
SD3410 90 degree
That helped me quite a lot, thanks.
What does the fresnel lens do exactly? I read that its for capturing more light.
luckyx182:
...
What does the fresnel lens do exactly? I read that its for capturing more light.
Yes.
Fresnel lenses consist of a series of concentric grooves etched into plastic. Their thin, lightweight construction, availability in small as well as large sizes, and excellent light gathering ability make them useful in a variety of applications. Fresnel lenses are most often used in light gathering applications, such as condenser systems or emitter/detector setups. They can also be used as magnifiers or projection lenses in illumination systems, and image formulation.
http://www.edmundoptics.com/technical-resources-center/optics/advantages-of-fresnel-lenses/
luckyx182:
What does the fresnel lens do exactly? I read that its for capturing more light.
In this application its normally to colminate the light.
Same as mounting it at the end of a tube.
If its come out of a pir sensor thats different, its designed to create zones or areas so that crossing a zone creates an output.
These normaly employ pyroelectric detectors which only respond to a step change.
They will not detect a continuous beam of light
in this case leave the lens mounted and just tape over the outer zones.
This will narrow the field of view.
However these things are often designed so animals wont trip them.
Putting it in a tube may lower the sensitivity so it wont work.
The fresnel lens is the bit that makes the whole thing work.
They are often filtered to the human body temperature to reduce false triggers.
This has a wavelength of 10,000 nM, and i know of no ir leds at this wavelength which could be used for a break beam type detector .
I'm wondering if the Fresnel lens can be manufactured so it would capture only tiny angle. I think it would be cheaper to manufacture it than to use ir sensor with small angular response. BTW anyone knows where the suggested sd5410 can be bought?
Boardburner2:
The fresnel lens is the bit that makes the whole thing work.
You are right I tried to put off the lens and it was triggering itself randomly.
luckyx182:
...
BTW anyone knows where the suggested sd5410 can be bought?
...
luckyx182:
I'm wondering if the Fresnel lens can be manufactured so it would capture only tiny angle. I think it would be
yes they can be had from edmund scientific.
put the detector at the focal point and you get a paralell beam the other side (simple lens theory).
Same at emitter end.
A toilet roll tube is the traditional means of experimentation.
A simple lens works perfectly, depends whats cheapest.
Wow, I didn't know it could be done with ordinary lenses. Thanks for suggestions!