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 Infrared Block detection circuits
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Author Previous Topic: Magnetic Strips -Will They Affect A Decoder Topic Next Topic: HELP WITH PBL SOUND
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David J Buchholz
Crew Chief

Posted - 12/09/2018 :  08:02:45 AM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
I have been unsuccessful in finding a source of kits, parts, plans, or information on SIMPLE infrared block detectors.

Simple. That they don't have to run crossing lights or other circuits, they just need to light up a control panel LED.

There will be a few truely hidden passing tracks on my North Coast Railroad that I would like to be revealed on the control panel as to whether there is a train in the block and whether it has cleared fouling points beyond the turnouts.

Since theses areas are accessible only from under the bench work, I cannot count on ambient light, and therefore must consider paired infrared emitters and receivers as my best bet.

Any info, links, diagrams and points of discussion are welcome.

Did I mention that I am a cheap bastard? Yeah, they gotta be cheap.

Dave "The cheap bastard" Buchholz

(If you don't believe me, just ask my wife)
Home of the North Coast Railroad.

Country: | Posts: 766

Bernd
Fireman



Posted - 12/09/2018 :  08:53:34 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
Ok Dave, I'm going to send you into brain over-load here.

Here's some info on infrared sensors and cheap by the way, just the way you like 'em.

First read this thread:
http://cs.trains.com/mrr/f/88/t/273355.aspx

Here's where to buy those detectors.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=IR Infrared Obstacle Avoidance Sensor Module for Arduino&_sacat=0

And some instructions on IR detectors from Dave Bodnar.
http://www.trainelectronics.com/IR_Train_Detector_5-2007/index.htm

That should keep you busy for a while. Now I need to read up on them so I can answer your questions.

Bernd



Country: USA | Posts: 3145 Go to Top of Page

Bernd
Fireman



Posted - 12/09/2018 :  09:20:32 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
More info. I labeled what the different LED's do on the circuit.



And the vendor on E-bay that Mel on MRR ordered his detectors from.

https://www.ebay.com/itm/IR-Infrared-Obstacle-Avoidance-Sensor-Module-for-Arduino-Smart-Car-Robot-3-wire/273397209398?epid=7022385474&hash=item3fa7be5936:g:Z~wAAOSwOvRba6Dc

All this circuit would need is a power supply and an LED for your control panel.

BTW, the bills in the mail for all this consulting on electrical circuits.

Bernd



Country: USA | Posts: 3145 Go to Top of Page

David J Buchholz
Crew Chief

Posted - 12/09/2018 :  10:59:51 AM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
Looks like I would need to invert the signal on the reflective sensor units that you have listed above. I can get 20 for $9. But must come up with the materials to power everything from the chip to the board.

Maybe I'm wrong. My impression is that the reflective version would turn on a LED when a detector gets a reflection into it off the bottom of a passing car above it.

Better for my purpose would be separating the emitter collector pair at an angle, so when something blocks the beam, the panel LED would turn on.

I could use one at fouling points on hidden sidings. The fouling point pair would be almost straight across the track. I say "almost" because if it is a right angle, you could conceivably be shooting between two cars, and not really clear of the fouling point, given a false clear lamp on the control panel. A slight angle would more likely catch a car body inbetween.

A block "occupancy" version would be even less perpenticular, shooting down a longer length of the siding to show the train is between properly beyond fouling points within the siding.



Home of the North Coast Railroad.

Edited by - David J Buchholz on 12/28/2018 10:50:09 PM

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Bernd
Fireman



Posted - 12/09/2018 :  12:55:19 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
quote:
Originally posted by David J Buchholz

Looks luke i would need to invert the signal on the reflective arduino style unites. I can get 20 for $9. But must cone up eith the materials to power everything and ful the signsl



I put in an order so I can play with them also. Going to need some on the future NY,V & N Rwy. anyway. Might as well start now.

Bernd



Country: USA | Posts: 3145 Go to Top of Page

potsy
Crew Chief

Premium Member

Posted - 12/09/2018 :  3:17:55 PM  Show Profile  Reply with Quote
Dave you need to talk to desert drover about this he seems to be the electrical GURU on the forum??


Mark



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David J Buchholz
Crew Chief

Posted - 12/09/2018 :  8:37:45 PM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
http://www.azatrax.com/two-ir-sensors.html

About half way down this page there is a section dealing with two sensors on the same path.there us a circuit diagram shown. It uses the same board and same sensors for both reflective and across the track. The connections to the circuit board are different.

The thing I note is, that of the four circuit board solders points, two of them seem to get swapped when changing from "across the track" mode to "reflective" mode.


Seems like this would flip the hot when on vs when off with out the need if additional parts to flip it back from the factory intended mode to the needed mode.

Anyone else seeing this? Is it REALLY that simple to alter?

If that is the case, I would have been disconnecting the led pair from the little circuit board to mount them into the road bed anyway!


Home of the North Coast Railroad.

Edited by - David J Buchholz on 12/09/2018 8:59:44 PM

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desertdrover
Engineer



Posted - 12/09/2018 :  9:43:39 PM  Show Profile  Reply with Quote
quote:
Originally posted by potsy

Dave you need to talk to desert drover about this he seems to be the electrical GURU on the forum??


Mark



Thanks Mark for your vote of confidence, however, I've been following this thread and it is all Greek to me. These infrared block detectors stuff is something I know nothing about. I'd hurt myself or someone else.



Louis
Pacific Northwest Logging in the East Coast
Post count: 2000 posts added to below count.

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David J Buchholz
Crew Chief

Posted - 12/09/2018 :  10:00:16 PM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
We know how to model flowing water, but flowing electrons will be the death of us all.

Home of the North Coast Railroad.

Edited by - David J Buchholz on 12/09/2018 10:08:04 PM

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Bernd
Fireman



Posted - 12/10/2018 :  08:38:23 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
quote:
Originally posted by David J Buchholz

http://www.azatrax.com/two-ir-sensors.html

About half way down this page there is a section dealing with two sensors on the same path.there us a circuit diagram shown. It uses the same board and same sensors for both reflective and across the track. The connections to the circuit board are different.

The thing I note is, that of the four circuit board solders points, two of them seem to get swapped when changing from "across the track" mode to "reflective" mode.


What I see on the Azatrax website is them selling you two LED's and two feet of wire for $4.50 and who knows how much for shipping. It doesn't include the sensor circuit board. Plus what I see there makes no sense using two emitter LEDs and two receiver LEds. You only neeed one of each to accomplish what you want to do.


Wait till I get my parts and I'll set up a test piece for you. The parts should be here by the end of this month if Santa is passing over China in the next couple of weeks. What I'm saying is that I'll build a test circuit for you. You can then decide whether to hire me for electrical design work or not.

Bernd



Country: USA | Posts: 3145 Go to Top of Page

David J Buchholz
Crew Chief

Posted - 12/10/2018 :  09:03:45 AM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
You are missing the point Bernd. Its not that there are two LEDs in place. Its swapping the solder points to go from reflective to across the track mode regardless of the number of LEDS in the circuit. Look at where the wires go to. It isnt the same . The connections have been swapped.

Home of the North Coast Railroad.

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Norton
Engine Wiper

Posted - 12/10/2018 :  11:56:33 AM  Show Profile  Reply with Quote
Dave,

The connections have been swapped because the LEDs/recivers are configured differently. In one they are in series and in the other they are parallel. When in series (the upper diagram) the train is detected when BOTH sets of LEDs/receivers are blocked. Only blocking one pair wont detect the train. In the parallel setup (the lower diagram), EITHER pair of LEDs/receivers will detect the train. If you are familiar with digital logic, the upper diagram is an AND circuit and the lower diagram is an OR circuit.

Does that help any?


The V & T lives in my garage. Soon...

Norton

Country: USA | Posts: 190 Go to Top of Page

David J Buchholz
Crew Chief

Posted - 12/10/2018 :  1:30:07 PM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
Norton,thanks for responding. My answer is that I'm not sure if it helps because I don't know enough about what I am trying to solve.

My thought process is that a sensor in reflective mode is active (and lights my panel lamp) because the receiver is now seeing the relected light from the emitter.

The across the track version becomes active and triggers the panel lamp becauce the receiver has had the light blocked from the emitter source.

So they are opposite in response.

I was wondering if by flipping the connections on the cheap unit, like those shown in the Azatrack diagram, if that was sufficient to flip or reverse the active state so the panel light comes on when the signal is blocked not when reflected.

The impression I got from the Azatrack diagram was to change from reflective to block modes, all that is needed is to swap the two anode (+) wires.

If that is the case, the emitter/receiver LEDs were going to be separated from the board anyway, so swapping anode connections would be about as easy as it could possibly get.


I dont know that answer. Waiting for a slow boat from China to show up with parts

Dave


Home of the North Coast Railroad.

Edited by - David J Buchholz on 12/30/2018 6:49:15 PM

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Bernd
Fireman



Posted - 12/10/2018 :  2:57:04 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
I went and read everything I could find on their web site about installing the Azatrack detection circuit. No where did I find where it said what state the output LED is when an object is detected. I'm going to assume that when something activates the circuit,the panel LED light will go on. In the "across the tracks" detection circuit the receiving LED is being activated since there is nothing blocking it's path until a car cuts across the light path. When it does the panel LED will go on. On the reflective when the receiving LED detects the IR light the panel LED will light.

Since you want an LED to light when you have a train beyond the fouling point I figured the E-bay. Also the reflective would be easier to mount from under the layout.

The circuit boards from E-bay are only good for reflective mode if that's the question. In either case it will take extra circuitry to perform both functions, reflective or across the tracks (blocking the LED light path).

Bernd



Country: USA | Posts: 3145 Go to Top of Page

David J Buchholz
Crew Chief

Posted - 12/10/2018 :  5:39:46 PM  Show Profile  Send David J Buchholz an AOL message  Reply with Quote
I am going to try swapping anodes as the first thing I do.

Home of the North Coast Railroad.

Edited by - David J Buchholz on 12/10/2018 5:42:52 PM

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Norton
Engine Wiper

Posted - 12/11/2018 :  02:45:35 AM  Show Profile  Reply with Quote
David,

No it takes a little more than just changing the Anode connection. But without knowing a little more about the internals of the board, we're guessing.

Bernd is right. There is no indication what the output LED is doing in each state of the detector. That makes it difficult for anyone without the circuit in hand to adequately assist in properly and completely answering your question. We can all guess but I would surmise that once you get the circuit boards in hand, you will know fairly quickly what to do.

Please keep us updated on what you find as this is actually an intriguing question.



The V & T lives in my garage. Soon...

Norton

Country: USA | Posts: 190 Go to Top of Page
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