Recommend a beam sensor?

[picta]

I am looking for a beam/curtain style motion sensor that has the smallest angle. I would like to be able to detect when our toddler wanders into mechanical room when the door is open. I am thinking that if I could find a sensor with a narrow beam I could place one at the low height and the second one at the 5', so that it can distinguish between the little guy and an adult walking through. Is this a the best way to solve this problem and could you recommend a suitable sensor? Thanks for any suggestions!

 

[BraveSirRobbin]

I'm usually not an alarmist, but these beam sensors have some type of IR emission I believe that I would not be comfortable with at a low height, especially in an area that is frequented often.  I am a bit worried about direct exposure to the eyes, especially to a young one.
 
Now, I have no scientific information to back this mind you, just voicing my concern.

 

[jpmargis]

I've used these for detecting over longer distances.  Works well, but it's probably overkill for you.
 
http://www.gatecrafters.com/product_detail_10999.aspx

 

[picta]

I was thinking more along the line of garage opener safety beam sensors. Since they are widely used, I hope they have been tested against harmful effects? I have a pair at the garage door now, will have to do more research on the type of beam they are using....

 

[jpmargis]

It's just an infrared LED - harmless.
 
The detectors that use a retroreflector are easier to install since the wiring is all on one side.

 

[Del91574]

I believe Amseco has a very small flush mount unit with separate analyzer/electronics, but may be an issue depending on mobility of the child....
 
I'd go another route before this personally.

 

[picta]

I believe Amseco has a very small flush mount unit with separate analyzer/electronics, but may be an issue depending on mobility of the child....
 
I'd go another route before this personally.

 
Is there another way to approach this? The only alternative I could think of is to use some kind of RFID tag, but that idea does not sit well with anyone

 

[potts.mike]

Could one of the ultrasound range finders from maxbotix be made to work? maybe one mounted above the door, assuming it samples fast enough to catch a toddler darting through the door.

 

[Del91574]

I don't know, but maybe something like a REX PIR above the door or the small pattern units like those Optex offers if it's critical, but based on typical PE beam patterns and what I know of toddlers, I don't think you're going to get reliable capture performance of the little person once they go from crawl to walk to whatever... They can be scary smart compared to most adults.

 

[picta]

I don't know, but maybe something like a REX PIR above the door or the small pattern units like those Optex offers if it's critical, but based on typical PE beam patterns and what I know of toddlers, I don't think you're going to get reliable capture performance of the little person once they go from crawl to walk to whatever... They can be scary smart compared to most adults.

You are so right about smart toddlers What type of Optex unit are you referencing? I am thinking perhaps to do it in a different way: install some kind of sensor that will be triggered only by adults (place it at some height, and be able to adjust the beam not to capture the youngster). Then have a quad PIR without pet-immune that will always trigger on motion, and if the "adult" sensor did not go off with it, we have a toddler alarm. Dose that sound like a good idea?

 

[Del91574]

A REX PIR, like a Bosch DS150 or 160I is relatively cheap and easily adjustable to cover a small area.
 
You could also do the old "pet alley" PIR trick and mount a PIR in the room at 3-4' to catch someone at chest height, but ignore the toddler.

 

[picta]

Thanks. I like the pet valley suggestion, I'll see if I could make it work.