Evansdesigns Motion Detector. Focus the beam?

I would suggest asking Evans directly.    They have tested these things and may have some answers for you.

Just to be clear, you are referring to this Evans product?

Note how they have a version for AC voltage power too.  That's a nice touch for O-gauge train transformers with Accessory output 14-16V AC.

I'm guessing they are integrating a so-called PIR motion sensor module though for whatever reason I could not find the term PIR in the Evans description.

That said, if this is indeed a PIR sensor, as stated it is a MOTION detector.  So if the train comes to a halt right in front of the detector, it will eventually stop the trigger.  This may be fine for your application.  Also, PIR sensors that I'm aware of detect thermal variations within a field-of-view as in human bodies that are just under 100 degrees against typical room temperatures of, say, 70 degrees.  This is so when used in burglar alarms they don't trigger on, say, curtains moving in front of an open window.  So the detector might sense an engine once it has "warmed" up but might not when you first start running an engine.  Then of course what about detecting rolling stock that never warms up.

Again, this is based on my assumption that we are talking generic PIR technology.  I think it would take some experimentation to fine-tune the focus or what I'll call the field-of-view for sensors of this type - with the milky-white multi-faceted lens.

Thanks very much. All I want to do is place a light under each building…I used old light bulbs and antique wired stands that my dad made. Maybe I will just use them with screw in bulbs.

I don't see the PIR motion detector as being all that useful in this application.  Maybe Evan's will clarify what technology this sensor uses?

Wouldn't a transmissive IR detector instead of a reflective be so much easier to use for this application? There is also magnetic detection which works quite well for this function as well.

Just to pick a terminology nit, your suggestion is to collimate the beam, not focus it.

@Bigboyrich posted:

Thanks very much. All I want to do is place a light under each building…I used old light bulbs and antique wired stands that my dad made. Maybe I will just use them with screw in bulbs.

I think you might have posted your response to the wrong thread?  I believe you meant to reply to this thread.

You can delete your above post...and then I will do the same to my post here...in the interest of tidiness.

Geez guys,

Stan has nicely shown the product I am talking about.

All I know is that if this sensor detects motion, it turns the switch on for 15 seconds and then it goes off.  3v to 12 v DC.

So, waive your hand in front of it, it goes on.  No more waiving and it turns off 15 seconds later.

Some users say that it can detect motion up to 3 feet away.

So, assuming it works, I'm not sure that I really need any more info than that.  If a train goes right by it, it should turn "on." :-)

Anybody try to collimate the beam?  Or, am I the lucky guy who has to pay $8 plus shipping to find out.   :-)

(My pile of small electronic stuff that I have bought and doesn't work out is getting kinda big.)

Thanks

Mannyrock

Your hand is organic and warmer than the surrounding objects, that's how a PIR sensor works.  If this is indeed a PIR sensor, it will not detect stuff like rolling stock.  Stan's comments are right on target.

But, . . .who says it is a PIR sensor? 

I sure didn't read that in the ad.   I used the example of waiving my hand only as a motion example.  The ad says that it can detect "motion" up to 3 feet away, not warmth.

Here is what the Ad says:        "Model Train Enthusiasts:  Use this sensor to detect your model train when it passes, to turn on a crossing gate signal further down the track.  The sensor will turn on the crossing signal, then turn off 15 seconds later automatically when the train is no longer triggering it."

How did this thread get off down the road about "warmth"?

Boy am I confused.

Mannyrock

I'll tell you what.  Why don't you buy a few and let us know how they work.

I wanted to do the same thing and found some boards on ebay that would do it just fine. They were called obstacle avoidance sensors - basically IR sensors with xmitt and receiver on the same board with a pot to adjust sensitivity.  Worked great , just needed a 5 volt relay board to to give me the dry contacts to work with.  The sensor boards were only like 20 for $13.00 - cheap.  Do a search - if you cant find them I will get you the number.   JP

Thanks JP, you've given me some other options to think about.

I guess for now, I'll just spend the $8.00 and see what it is.  Maybe the other commentators are right, and it only works off of warmth detection.

Hard for me to believe (but I may well be wrong) that an $8.00 thing that looks like a marble could detect a momentary change of temperature from 3 feet away. 

I'll will check it out and report back.

Thanks for all of the comments from everyone.

Mannyrock

@Mannyrock posted:

Hard for me to believe (but I may well be wrong) that an $8.00 thing that looks like a marble could detect a momentary change of temperature from 3 feet away.

Look around, there are tons if cheap IR sensors for motion detection.  The PIR sensor is just a small part, usually behind a translucent white cover, sound familiar?

Yes. Please report back when you get the module.  If you read the user comments on the Evans site I believe there was one that said it worked to 8 feet or something like that.

After seeing that comment, I'm even more convinced it is using PIR technology.  As shown in above photo, and in photo I posted earlier in thread you can buy bare-bones PIR modules for a couple bucks in small quantity.  And then there are companies that integrate these modules with suitable connectors - about $10 in small quantity.

In the last century when this technology became mainstream in motion detectors, the underlying PIR modules were quite expensive because the technology was new.  I wouldn't be surprised to find out some patents have recently expired or some company developed a highly integrated IC chip that performs all the signal processing and is cranking them out by the zillions.

Anyway, the dead give-away is if the Evans sensor has a milky-white multi-faceted lens.  It's hard to tell in their photo but easy to see in some other photos I've shown above for other motion detector products.  There are dozens of facets on the milky-white lens.  That's the "genius" of whoever invented this.  Just google PIR detector or whatever and it's really fascinating how/why it's done this way and the underlying electronics it takes to do this.  The every-which-way scattering of the incoming thermal or Pyroelectric (that's the "P" in PIR) energy makes it difficult to analyze how collimating, focusing, or whatever you want to call it will affect the detector.

As for train motion sensing, as I stated earlier, I would be fascinated to hear the Evans module can detect motion in objects that are at ambient room temperature even if moving.  Again, I understand that nowhere does it say the Evans device uses PIR technology.

Maybe they use RIR (Reflective Infrared Sensors) to detect the reflected presence of the train.

     Wow, . . . with all of the folks on this Board who laid out $175 just to "test" a new Menard's beta engine, or wouldn't blink at spending $1,200 on a steam loco, I'da thunk that someone by now would have sprung for $8.00 to test and dissect this very curious switch!  :-)

   If Evans had just advertised this as a "beta unit" asking for volunteers to write a review, they would probably have sold out by now.

   Guess I'll go first.

   But this means no lunch money for two days.  :-(

Mannyrock

If the milky-white globe doesn't work out, try Azatrax.

They have a time-adjustable relay module with two IR sensors that can be mounted any way you want, to detect train motion and activate another component. I have one with the sensors imbedded in my foam topper, angled and pointing up to detect when a train passes overhead. 

It triggers a Fastrack switch in the thru position on a 20 second delay (to allow enough time for a long consist to pass by) and trips the switch to divergent so that when the train comes back the other way it takes the divergent route.

Pricier than growing your own on the internet, but works very well.

@Mannyrock posted:

     Wow, . . . with all of the folks on this Board who laid out $175 just to "test" a new Menard's beta engine, or wouldn't blink at spending $1,200 on a steam loco, I'da thunk that someone by now would have sprung for $8.00 to test and dissect this very curious switch!  :-)

We didn't have $8 left over.