A Signaling Circuit For Your Model Railroad (218)
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- เผยแพร่เมื่อ 25 ก.ย. 2021
- Electronics can be a problem for many model railroaders, especially if it requires actually building the circuits necessary to control accessories and other devices. Int this video I'll share with you a design for a fairly simple optical detection and signal control circuit that I sue on the Piedmont Southern layout to control traffic across a river crossing on a single width bridge shown in video 217. In the description below I'll include links to the website where I found this circuit and to my personal website where you can download closeup photos of the circuitboard and my hand drawn wiring diagram. So let's get started.
Here are the websites and parts info I mentioned in the video. I will try to have the plans and photos on my website by early this week so please check again later in the week. Redrawing the plans and fully annotating them and the photos just takes a while and I haven’t much time to do it all along with making and editing the videos.
My website larrypuckett.wordpress.com
Rob Paisley's website: www.circuitous.ca/CircuitIndex...
and www.circuitous.ca/PhotoDetecto...
Below is a parts list and sources. But first a note about substituting parts. Although I bought a lot at All Electronics, most of the electrical components can be purchased anywhere. However the relay and phototransistor are exceptions. Actually you could try any visible light sensitive phototransistor and some infrared ones will work well too-the one I used and listed is an IR device. Remember that IR devices are usually most sensitive around 940 nm whereas visible light runs from about 400-740nm. As for the relay pick a small 12VDC pc mount DPDT relay, with a coil resistance over 500 ohms. The one I used and listed is rated about 700 ohms. The perforated phenolic circuit board material is getting hard to find, especially the kind without copper cladding. But there is nothing special about it otherwise. You might be able to use the kind with copper dots around each hole but I have never tried it. In the parts list below I placed a * next to the ones I used. I used what ever solid wire I had on hand for the connections between components but smaller is better. In some cases I even used the leftovers after cutting the leads off the resistors and capacitors. All these companies sell small diameter solid wire-I would use 22ga or even smaller. The really small stuff in the photos is 30 ga wire wrapping wire.
Jameco.com
*Perf board 4.5x6” sheet #616690
Phototransistor visible light #1108144
*Relay 12VDC DS2Y-S-DC12V
Mouser.com
Phototransistor IR #604-WP3DP3BT (Mouser says it is the same as the DigiKey one).
Digikey.com
*Phototransistor IR #754-1468-ND
Allelectronics.com Values enclosed in (1) indicate the number required per board
* 1N4001 Diode 1N4001 (1)
* 2N3906 PNP transistor 2N3906 (1)
* ICS-8 Eight pin IC socket (1)
* LM393 Comparator (1)
* 291-10K 10K ohm resistor 1/4W (2)
* 291-1M 1 meg ohm resistor 1/4 W (1)
* 291-2.2K 2.2K ohm resistor 1/4 W (1)
* 291-470K 470K ohm resistor 1/4 W (1)
* TER-405 5 pos screw terminal (1)
* TER-403 3 pos screw terminal (1)
* 10R50-C 10uF 50v electrolytic capacitor (1) Note: these provide the delayed switching of the relay and give about 1 sec per 1uF. For less delay order a smaller value. For a longer delay use a larger value. A 10 uF device gives about 10 secs. - แนวปฏิบัติและการใช้ชีวิต
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Excellent video. You gave easy to follow tips and instructions, the parts list and website details also help. Will be looking to give this a try one day.
Ron.
Great Larry, Many Thanks for such an interesting Video.
Thank you for sharing. Enjoyed.
I wish I could give multiple thumbs up. This was extremely helpful!
Great video Larry
Enjoyed the video find it very helpful.
thank you for your detail video
Awesome video Larry i enjoy watching your video.
Robert Trains
Thanks Larry! 🐾🚂.
Great video and tips, like to see more on using track power for lights and switches instead of outside power source, keep up the great work
Very cool! Love these types of DIY electronics projects for model railroading. I think for this type of application, you could remove the relay entirely from the circuit and just use a properly-rated BJT or MOSFET to switch them. You would lose the NC contact, but you could add it in using a NOT gate.
One thing you could try is using twisted pairs for your signal wires. It's what the auto manufacturers do on their data buses (CCD, CAN, etc.). Try it; it might be a simple and effective solution to address any interference you may be seeing. Nice video, BTW!
Very interesting thanks very much.
So nice the world's best teacher
Exactly what ive been looking for 😊 uk 🇬🇧
I've built something similar with even simpler parts. 2 parts actually. Using the Isolated track as the trigger voltage Using the wheels of the Lionel locomotive and cars to complete the circuit....by using a relay off the signal wires off the tracks, this method will enable you to use a separate AC or DC power supply or even older AC Train Transforme, AC or DC because it really has no effect on your accessories, they can probably run more efficiently on DC being a bushed Universal motor or light bulb. If you have LED's just pay attention to your DC output polarity and you'll have no problems. So using this method enables you to basically provide 💯% of your trains locomotive and car lights or accessories to have almost all its power, minus the few watts to trigger the solid state relays. The accessories themselves will have their own separate power source(s) being the 2 power sources are Isolated from themselves either DC or AC could be used as a input or output. So being I run 3 rail AC Lionel sets the relay requires the source or trigger voltage to be 4-15 VDC. I use a solid state relay which has 2 separate lines, so one relay can control 2 separate or combined power supply sources. Using the CRYDOM D244OD, with 2 separate circuits for easier distribution or a different use to another accessorize? That's your call upon how you use the 4 output spades....? But the trick is if using a AC train transformer the trigger voltage is in AC form. The relay is looking for DC or another crude form of Dirty half-wave DC. For this I use the Zerner Diodes coming from the track signal wires as the wheels and axle complete the switch on the tracks, we'll have AC anywhere from 6-18 VAC going into the solid state relay. It needs to be converted into a crude form of DC for the relay to pick/close. So running a Zerner one way check valve basically into the relay and the other Zerner on the way out of the second pin of the relay it is more than enough to pick these relays for a solid contact open and closed switching system. This way any high loads like of the solenoids and incandescent light bulbs pull will be on a completely Isolated source Rather than sucking the life out of the track power to activate your accessories. The dimensions of this relay is pretty small 2" X 1¾" has 4 wire pins for the 4-15VDC inputs, and 4 spade outputs 2 per channel basically and is way overkill for this application. These are rated for crazy loads of 120-240 VAC @ 40A. So the few amps of AC or DC your running through each channel won't bother these relays in the slightest. But otherwise great video, I just wanted to Share with the community about another simple and similar method or approach to these special features for the board layouts. The nice thing is their size and easy mounting abilities to make it easily concealed or switched out if they ever fail. If that ever happens you'll be the first to know. Mine have probably hundreds of running hours on them without failures, so it is pretty robust to say the least. Thanks and if anyone has any questions please feel free to ask. Hopefully Screwtube will actually send a notification to me and I'll get back to ya. Thanks again and happy training. 😊
Oh yes and the fact I'm using a Zerner Diode as a means of rectifying this circuit I've found that a standard schottky general purpose Diode will work just fine as well like the 1N008 or 1N5408 will work just fine too. I chose to use a switching diode to act like a voltage regulation system, so if my track power happens to jump into the 20+Vts coming off the tracks, these diodes will keep the power from going higher by acting like a gate valve in a sense. This protects your solid state relay or SSR from any forms of power spikes. Using a AC Lionel or A/F train transformer which usually has a maximum output around 16-20 VAC not including whatever your locomotive is going to eat up plus anything with lights your pulling, the track power is usually around 6-14 VAC. The SSR is capable of a input of 4-15 VDC. So after the Diode chops off half a sign wave we're left with around 5-13 crude VDC after the Diodes which basically as perfect as we're going to get.
Nice vid.
For a similar detection project, I used IR detectors mounted in a hole about an inch deep between track ties and IR lights mounted directly overhead on my ceiling. The IR lights are readily available and work reliably in all visible lighting conditions. My room lighting LED fixtures would not produce reliable operation.
Also, in the circuit you refer to, it would be easy to change the fixed resistor identified as 1M to a trim potentiometer to allow some adjustment of the time delay.
Yes, I have another location where the phototransistor is under a bridge and I put the IR LED on the bottom of the bridge and it works great.
Larry,this is Don. An easy solution to your sensitivity problem is a marks a lot. Paint the led and it will reduce it's sensitivity. After the ink dries you can apply another coat if needed.
Larry great info. I use NCE Light-Its to control my Signals on my Layout they get an address and they are linked to my BD20s when a train enters the block the signal changes. On my turnouts same thing when the turnout changes from closed to open the signals change from green to red. very simple method I started with Azatrac signal boards but I had to place sensors on the track They worked well but not a fan of using any sensors. But there are many ways to setup signals
Thomas, I have ordered a pack of 3 NCE Light-Its (not received yet) as they seem from the description very versatile, and even though I don't know how to use them yet, they seem like an inexpensive solution; the Atlas universal controllers work out very expensive as one is needed per signal head from what I have read. I wanted to avoid a signal system controlled by DCC addresses but I'm guessing (?) that once NCE Light-Its have an address it will be simple and automatic without having to tap in addresses constantly on my NCS pro-cab.
Thanks for having a great TH-cam channel. Have you ever looked at the detectors and block lights made by Model Train Techology , They advise working in any light , I’m not that great at the electronic thing , soldering decoders is it but would like some detection on parts of my layout.
HELLO LARRY ITS IS RANDY AND I LIKE U VIDEO IS COOL THANKS LARRY FRIENDS RANDY
I had a problem just like you had with the sensor's on my crossing gate board. You have to be sure wires from the sensor routed away from DCC buss and feeder wires and switch machine. also on the crossing gate pages he shows a filter that might work as I had to use it in case.
Thanks, I’ll look for his filter circuit. I did try routing the wires along the wall away from the DCC bus which runs down the middle, but that is the narrowest place on the layout and I guess I still wasn’t far enough away. Oddly enough I had no issues with the same phototransistors and the crossing gate circuit.
@@TheDCCGuy If you go to the Crossing gate section and then look for Additional grade crossing CKT's and scroll down to Adding Cap's to ckt's inputs. Hope it helps. When I installed one of the crossing boards I had problems as I had a double track with a few current detectors and a few feeders.
It looks like Rob's site is no longer supported as of 7/12/22, but all the schematics are still there.
So, do you need to add an IR transmitter LED so that it breaks the IR light and actuates the signal? Could be used for crossing gate signals too?
I think I explained all this on the video. If you use an ir phototransistor you can use an ir LED in very low light settings. I have not had to and find they work well even in low light train room settings but your results may differ.
Another great video. Larry what happened to Rob Paisley
I think he just got tired of dealing with folks contacting him via his website or lost interest. He was always difficult to deal with. Even when I was promoting one of his products in one of my books it was like pulling teeth to get him to answer questions. But his postings certainly provided a lot of good information on model railroading circuits.
@@TheDCCGuy Thanks (not all of us Canadians are quite that bad), I wish I'd seen his site. Happy Christmas Larry
I wasn’t aware he had completely removed the website, too bad.
Hi Larry,
I have a question about a circuit I built that I think I copied from you. It consists of a 220 ohm resistor, a 16v 1500 (2200) uF cap, a 50V 1.5A bridge rectifier and a potentiometer soldered on a board. I usually right everything down as a diagram / work sheet but for the life of me, I can't find it. I did mark the output wires "lights".
If by any chance this was one of yours, please send me a link to your build or what the build was for? I can send you a pic of one that I built.
Thank you,
Pete
Take a look at video #101.
I would like to see a system that shows turn out position and block occupancy that's a simple plug-and-play that does not use computer software such as jmri.
When you find it let me know, I’d like that too!
I know this is an old video, but I figured it was worth a try to ask. I've built this circuit twice using the exact same components, but I cannot get it to work properly. The only way I can get the relay to trip is by varying the input voltage from low to high. It seems the comparator side of the circuit is not working correctly. I've been over it a dozen times, tried different resistors for the 470K, but no luck. Any suggestions would be most welcome. Thanks...
Let me take a look back at it. Remind if I don’t get back to you in a few days but not using this thread, start a new one. I get so many comments old ones disappear after a few days.
I made two of these using the circuit as demonstrated in the video so I am not sure what is going on. Unfortunately Rob Paisley who developed the circuit is no longer supporting his website and refuses to answer emails. All I can suggest is recheck all your wiring and connections and also check your power supply voltage, it should be 12VDC. I just rechecked one of mine and it works great in 12VDC, not so on 9VDC.
Larry, thanks for the replies. I went ahead and built one of the circuits on Ron's page that does not contain a delay and it works great.Then I went back and looked at this circuit with the delay, triple checked everything, but still no luck. I'll keep at it, something seems amiss with the comparator part of the circuit. Appreciate all the videos you put up, I'm learning a lot. Regards...Lou
Sorry, I meant from 0 to 999 seconds, not minutes.
Site for Rob not found
Try it now, I had one too many “i”s in circuitous.
Wouldn't current sensing be better than using infrared LEDs ? Isolate the whole block, power it independently with a current sensor attached so that anything in that block would be detected for the entire length going both ways.
Yes and no. The issue is I already have current sensing detectors for that block so optical detectors allow me to use both at the same time for different purposes.
@@TheDCCGuy I really don't understand now, if you already have current sensing you really don't need the infrared sensors. You should be able to tie your existing current sense to the same ckt that your are using for your infrared sensor. Just replace Q1 (LED receiver ) with a 2n3906 or equivalent then connect the current transformer sense line to the base of that transistor , you may have to clamp the voltage with a diode and also limit the current into the base with a resistor but that is pretty simple and shouldn't require too much math if any because you should be able to do it experimentally. Any ways good luck, you always do a nice job with your videos.
No, to use a current sensing detector I’d have to isolate just the shorter section encompassing the bridge and its approaches from the rest of the block. And that would require installing a second set of detectors (one for each track). In fact I might have to cut the one long block into 3 shorter ones which would further increase the number of detectors and complexity. Trust me, this is the simpler method for a block within a block detection.
For some reason the video isn't playing for me in that there's nothing on screen ? Don't have a problem with any other videos ?
I have no problems with it and no one else has reported an issue. Reboot and try again.
The links to Rob Paisley's website no longer work.
It appears he finally took it down. Too bad as it was a great resource.
Have you had any luck contacting Rob Paisley lately?
No, he has not responded to two emails I sent him recently, however he updated his website on August 27th so I assume he is monitoring the email address listed.
@@TheDCCGuy Would you please let me know if you hear from him. I'm trying to buy some boards.
@@TheDCCGuy His Website now says "This site no longers supported" His misspelling not mine.
I had not seen that, I’ll check around and see what I can turn up. The circuits still work, you just have to wire them by hand on perf board instead of using his circuit boards. Too bad if he has suspended operations, but I guess it is a sign of the times.
Seems like Rob's site is down... does anybody have an email to contact him?
I think he just shut it down son e he hasn’t supported it in a few years.
@@TheDCCGuy are there alternative sites with comparable items?
I just found an archived copy of his site. Download what you think you might want fast as you never know when these things will disappear again.
web.archive.org/web/20150206004312/home.cogeco.ca/~rpaisley4/CircuitIndex.html
So my plan is to purchase all the pieces from the list and try and build one myself. The only thing I don't understand is the diagram you drew? Is there a picture of it somewhere? By the way your videos are simply amazing. Just found your channel yesterday and will be following you from now on.❤❤❤
Did you read the description for this video?
Hello Larry,
Great video. I learn so much from you. Please "keep'em coming". Question, could the output to the LED's also be used to power another relay that could be used to power a Tortoise switch machine that would insure a turnout was correctly aligned? I'm still using DC. Thanks. Donnie
The circuit drawing and the annotated photos of the circuit board are now available on my website (larrypuckett.wordpress.com).