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Offline river6109  
#1 Posted : 12 March 2015 10:58:45(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Hi,

I have been pondering whether or not it is possible to replace K - switching tracks, a.) they are not 100 % foolproof, b.) they take up 1/2 track, c.) the unit price could be reduced,

I have successfully installed other optocouplers for my braking modules and ESU servo motors, via a switching track (16 volt AC) ESU servo motor 5 volt DC) and they work just fine. at the moment the idea is with an electronic technician as I was unable to get the reflective optocoupler to work and most probably have ruined the infra red led and there seems to be more components needed as I anticipated, voltage regulator, digital pulse regulator, rectifier and a resistor, however most of the components are not needed if you you use a voltage adapter from 240 volts down to 5 volts DC.

the concept behind the idea is as follow: a loco goes over the reflective optocoupler and hopefully the slider creates a reflection and activates a pulse via the optocoupler receiver & responder (16 volt AC), infra red led (5volt DC).
If it works and I can't see any reason at this moment why it shouldn't work and when it does it opens up several opportunities to install them for different reasons and not just activating a braking module.
the component fits nicely between 2 sleepers and would look prototypical as other railway companies use sensors in this way.
We've had situations whereas a switching track activated signals, turnouts etc etc. with the loco's slider but than we had trailing carriages which also had sliders and re-activated some of the processed actions, we than had to add a second switching track to mute the first one and further down the line re-activated it again after the whole train has past the first switching track. this method may still be valid but you wouldn't need a whole track anymore to do this.
you could put another optocoupler as far as a sliders length.

a reflective optocoupler is about A$ 3.50, a 5 volt 3 Amp power supply is about A$ 26.00 and you could use a lot of optocouplers before you reach 3 Amp's

the interesting thing about this whole exercise is: my knowledge regarding electronics is 00001 %.

it would be also interesting if this method could be used when the layout is computer controlled ?

its just another thought roaming around my brain.

one more revelation: I have disconnected the contact from the track on the switching track and therefore the power applied to the contact switches is AC.

regards.,

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
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Offline Martin T  
#2 Posted : 12 March 2015 14:47:25(UTC)
Martin T

Sweden   
Joined: 02/01/2006(UTC)
Posts: 872
Location: Stockholm, Sweden
Hi! Smile

I did not successfully manage to implement reflective sensor, so I moved over to IR-LED under the loco and a IR-sensor (Hamatsu 4810) in the track. I was inspired by Perz solution, but didn't want to go all the way using indexed loco feedback (The loco is transmitting it´s identity by modulation of the IR-LED to the sensor).

Even though this system is not reflective, I ran into some issues from start, which might be valid for a reflective system as well. They are:

1) Optical sensors are dependent of some contrast to the ambient light. This means I had to replace my halogen armatures with LED-based armatures. The IR-content from any filament based illumination will totally block the IR-sensors. (I avoid Fluorescent lamps because it interferes with certain video frame rates)

2) Any light source in the train room having IR-content (the sun included) will add noice and reduce the amplification within the sensor. This is much harder to detect and typically only gives false or no detection only in worst case conditions.

3) All wiring around the sensor (power feed, signal out and ground) needs to be kept short and in most cases also de-coupled by a fast and suitable sixed capacitor to suppress induced voltage spikes.

4) Avoid to power the sensors from the track. The track power is "too dirty". Any short circuit along the track, such as a de-railed car will shut the sensors down, or even make them false trigger.

With these things managed properly I found the optical detection system extremly reliable, compact and easy to fit where ever required.

ThumpUp
Regards / Martin T
Click your way over to me in Marbrodal in Sweden: http://www.xn--mrklintg-0zaq.se/index_e.html
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Offline river6109  
#3 Posted : 12 March 2015 17:24:44(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Martin, thanks for the input, have you got any part numbert or picture to illustrate your option ? it would be very much appreciated.
on the question of dirt and circuit shorts I've separated them from the layout already at this stage still using switching tracks.

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
Offline fkowal  
#4 Posted : 21 March 2015 02:12:20(UTC)
fkowal

Canada   
Joined: 01/02/2012(UTC)
Posts: 69
Location: Toronto
Hello John.

Take a look at www.azatrax.com They have an "off the shelf" Infrared Train Detector that is a viable substitute for contract tracks.

Frank
ps. I enjoy your posts immensely.
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Offline river6109  
#5 Posted : 22 March 2015 05:09:46(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Frank I'm still waiting for the results from the electronic engineer but I have to go there anyway he has repaired a unit for us and he has to make some adjustments.

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
Offline river6109  
#6 Posted : 09 June 2015 03:20:11(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Hallo there, any one listening ? I've got good news, the opto coupler is now working and in another 2 weeks I will get the details, the only draw back, its not directional independent whereas the switching track is.

it works with my layout as I don't have trains moving on one track in both directions.
the moment I'll get the circuit board finished I will post it here with the results. (video)

John

https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
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Offline perz  
#7 Posted : 10 June 2015 00:17:51(UTC)
perz

Sweden   
Joined: 12/01/2002(UTC)
Posts: 2,578
Location: Sweden
Originally Posted by: river6109 Go to Quoted Post
Hallo there, any one listening ? I've got good news, the opto coupler is now working and in another 2 weeks I will get the details, the only draw back, its not directional independent whereas the switching track is.

it works with my layout as I don't have trains moving on one track in both directions.
the moment I'll get the circuit board finished I will post it here with the results. (video)

John



I think you could combine two of them to get the direction dependence.
Offline cookee_nz  
#8 Posted : 10 June 2015 03:12:23(UTC)
cookee_nz

New Zealand   
Joined: 31/12/2010(UTC)
Posts: 3,948
Location: Paremata, Wellington
Originally Posted by: perz Go to Quoted Post
Originally Posted by: river6109 Go to Quoted Post
Hallo there, any one listening ? I've got good news, the opto coupler is now working and in another 2 weeks I will get the details, the only draw back, its not directional independent whereas the switching track is.

it works with my layout as I don't have trains moving on one track in both directions.
the moment I'll get the circuit board finished I will post it here with the results. (video)

John



I think you could combine two of them to get the direction dependence.


I was thinking just the same thing, with two you should be able to get direction sensing without any problem.

John I'm looking forward to seeing the finished article, hopefully it will be a 'turn-key' solution, it will connect almost exactly the same way the current flipper track does because that's the big advantage for Märklin, the fact that it's easy for (almost) all their customers to understand and to wire up.

Cheers

Steve
Cookee
Wellington
NZ image
Offline river6109  
#9 Posted : 11 June 2015 03:47:23(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Steve and Perz, your option has to be investigated, the problem I can see unless you can mute one out what ever direction you're going, both optocoupler would respond when a loco drives over, for an example, in a siding you have 2 signals one on each end, the moment you would go over both optocoupler , both signals on both sides would turn green for instance. the same would occur if you have turnouts attached to it as well, if its just station lights this would be perfect but than you wouldn't need 2.

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
Offline rorosha  
#10 Posted : 11 June 2015 05:09:13(UTC)
rorosha


Joined: 06/08/2014(UTC)
Posts: 57
Location: MECHANICSBURG PA USA
Originally Posted by: river6109 Go to Quoted Post
Steve and Perz, your option has to be investigated, the problem I can see unless you can mute one out what ever direction you're going, both optocoupler would respond when a loco drives over, for an example, in a siding you have 2 signals one on each end, the moment you would go over both optocoupler , both signals on both sides would turn green for instance. the same would occur if you have turnouts attached to it as well, if its just station lights this would be perfect but than you wouldn't need 2.

John


What you're talking about has been done a multitude of times already. Take a look at http://home.cogeco.ca/~r...ley4/PhotoDetectors.html - the very last schematic on the page "Exclusive OR Phototransistor Circuit", for one of the simpler implementations

For the Model Railroader with an aptitude in electronics, Rob Paisley has published quite a few interesting circuits which could be used as is or as a starting point for your own design. Take a look, http://home.cogeco.ca/~rpaisley4/CircuitIndex.html

Rodger
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Offline river6109  
#11 Posted : 11 June 2015 17:37:43(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Rodger, thanks for the links, at least I bought my idea to light and had some interest from other members, the internet is a wonderful tool and one can if you understand electronics get some vital information from it.

I will try to understand the schematic or read the article more times over and see if i can make any sense of it but as you said it may has been used in America for many years but never heard or seen of it on the European market for Märklin 3 rail or 2 rail.

my proposal or the idea may differ slightly, a.) input power supply 18 Volt AC is needed and the output power supply is also 18 volt AC suitable for Märklin or similar braking modules. My particular braking module was based on an IEK module

one of the samples from the 2nd link: A Test Bench Power Supply (18 Volt AC input power) output power between 0-15 Volts DC
The next circuit is a classic on every LM317 datasheet. It's simple, reliable and a great place to start before building more advanced circuits.

every circuit has got its own usage and may differ from one to the other and some of them may not work because of the input and output Voltage and there is also the question how many slave circuits can you add to the master circuit board and the list could go on and on and I'm sure the link you've provided with an electronic expert behind it would be able to produce one for your particular needs

another point I like to make the advantage with my proposal is the current slider can be used to activate it but this doesn't mean the links you've supplied can't do the same, the other point is how much is it all going to cost and I will be able to say this in another 14 days, furthermore will it be attractive enough for modellers to abandon their K-track switching track and try this version ? also how could it work with a C-track without doing major alteration to the middle contact.

I'm sure there are other benefits associated with reflective photo sensors but i haven't explored these as yet.

my main reason as mentioned at the beginning was the unreliability of Märklin switching tracks and the C-track micro switches are also part of this dilemma like the turnout solenoids for C-tracks.

I also would like to ask you to explain to us how a reflective sensor or 2 could work in both directions independently and thanks for your input, very much appreciated

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
Offline rorosha  
#12 Posted : 11 June 2015 19:11:01(UTC)
rorosha


Joined: 06/08/2014(UTC)
Posts: 57
Location: MECHANICSBURG PA USA
Originally Posted by: river6109 Go to Quoted Post
Rodger, thanks for the links, at least I bought my idea to light and had some interest from other members, the internet is a wonderful tool and one can if you understand electronics get some vital information from it.

I will try to understand the schematic or read the article more times over and see if i can make any sense of it but as you said it may has been used in America for many years but never heard or seen of it on the European market for Märklin 3 rail or 2 rail.

my proposal or the idea may differ slightly, a.) input power supply 18 Volt AC is needed and the output power supply is also 18 volt AC suitable for Märklin or similar braking modules. My particular braking module was based on an IEK module

one of the samples from the 2nd link: A Test Bench Power Supply (18 Volt AC input power) output power between 0-15 Volts DC
The next circuit is a classic on every LM317 datasheet. It's simple, reliable and a great place to start before building more advanced circuits.

every circuit has got its own usage and may differ from one to the other and some of them may not work because of the input and output Voltage and there is also the question how many slave circuits can you add to the master circuit board and the list could go on and on and I'm sure the link you've provided with an electronic expert behind it would be able to produce one for your particular needs

another point I like to make the advantage with my proposal is the current slider can be used to activate it but this doesn't mean the links you've supplied can't do the same, the other point is how much is it all going to cost and I will be able to say this in another 14 days, furthermore will it be attractive enough for modellers to abandon their K-track switching track and try this version ? also how could it work with a C-track without doing major alteration to the middle contact.

I'm sure there are other benefits associated with reflective photo sensors but i haven't explored these as yet.

my main reason as mentioned at the beginning was the unreliability of Märklin switching tracks and the C-track micro switches are also part of this dilemma like the turnout solenoids for C-tracks.

I also would like to ask you to explain to us how a reflective sensor or 2 could work in both directions independently and thanks for your input, very much appreciated

John


As far as "differing slightly", those points are irrelevant, by building to require it to take 18 volts AC increases the cost of your design. By using a DC input voltage to the circuit, the rectifier, filter, and regulator are not required. If only one circuit is used, then it is not a problem, but if more than one circuit is used, the replication of that part of the circuit is an unneeded cost. As far as the output is concerned, what you want is a simple contact closure, as in a relay, or simply a transistor to pull the output to ground (basically "O")

For a power supply, the most economical approach is to use a preassembled power supply, something similar to the Märklin 66365. The Märklin 66365 could easily supply power to dozens of detector circuits without being overloaded. If you did not want the expense of a genuine Märklin power supply, check with your local electronics supplier and find one that will work for a fifth of the cost of the Märklin power supply.

For your solution to be truly viable, it needs to work with more than just "K" track. It really needs to work with "C" track as well. Because of the construction of "C" track, an integrated reflective sensor may not be the best choice, or even at all usable.

Also, even with optical sensing, you still have the chance of long pulses. If the train is moving slowly, the pulse will be longer. The length of the pickup shoe and speed of travel will determine the length of the pulse. If the pickup shoe stops over the sensor, which is as likely to happen with optical sensing as with mechanical sensing (Märklin switching track), it will generate an extended pulse. What would be needed is a "One Shot" circuit between the sensor and the actual output circuit. A good solution would be an NE555 (or NE556 double) timer, used in a monostable configuration.

Your engineer friend should be able to help you understand the basics, and to give you some guidance.


Now, for what you really want to know, direction sensing. Direction sensing (optical or magnetic) requires two sensors. The way it works is the first sensor detects presence, sends an output signal, and at the same time inhibits the second sensor from sending it's output signal. That gives a signal in one direction. Sensing in the opposite direction - the second sensor detects presence, sends an output signal, and at the same time inhibits the first sensor from sending it's output signal. The two outputs indicate the direction of travel.

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Offline perz  
#13 Posted : 12 June 2015 00:06:47(UTC)
perz

Sweden   
Joined: 12/01/2002(UTC)
Posts: 2,578
Location: Sweden
I looked at using reflex detectors many years ago, but I didn't find one with a good form factor. Now I looked around again and found two different ones that look like the one John showed. They have different height. The thicker one would be perfect if you mount it on a circuit board underneath the k-track. Then the other components could be on the other side of that circuit board.

The thinner one, with longer leads, would be possible to use with C-track. You then need to drill 4 small holes through the C-track for the leads. I haven't tested that with the reflex detector, but with an other type of IR sensor. It was rather easy. But not as easy as with the k-track of course.





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Offline river6109  
#14 Posted : 22 June 2015 18:00:51(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,636
Location: On 1965 Märklin Boulevard just around from Roco Square
Hi everyone, today I've got my circuit board and will most probably on Wednesday get smd components for it, than make sure everything is soldered on in the correct way on a new circuit board and than its just a matter of days to install it on the layout between the sleepers.
I like to see if I can get one which would work independently in both directions, I can't see it personally unless you add more electronic components to it, the result could be the price would be higher than the current switching track.


John,
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5 years in Destruction mode
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