lionelsoniConnect the negative terminal of both LEDs to the negative terminal of the 12-volt supply.
I am not sure which wire on the LED is negative. There is one red and one yellow. The yellow has something (possibly a diode?) in its line. Can't fine anything in the description of it on line to indicate which is which. I have several so if I ruin one by getting it wrong, at least then I'll know. I would have a 50/50 chance of getting it right. Any ideas?
I wired up the toggle switch to the turnout and it works perfectly. I did notice that in one direction, when the turnout coils retracted the operating rod it would get stuck like it is overtraveling. I was able to glue in a small block of wood to prevent overtravel, and it works fine. The turnout switches fine and should work perfectly this way.
Terry Thomann Fredericksburg, Virginia That is me on the left. My brother got the train TCA 09-64381
I will check previous posts to see if you said where you got them. There might be something on the internet. Or, if you see this first, post a link to the vendor.
I found your link. The web-site picture shows red and black leads, which is almost certainly positive and negative respectively. However, red and yellow is worrisome. Red might still be positive--or not. You might want to try to contact them. The thing in series with the lead is probably a ballast resistor, not a diode, unless there are two things in series.
I looked at the web site again. I don't see any lumps in their pictures. Do your LED assemblies resemble their picture at all? If you can get access to the actual LED, you may be able to identify the cathode, which often has a flat place on the LED's flange next to it. That will be the negative side.
Bob Nelson
Bob,
The LEDs I got do look a lot like the pictures but as you say the pictures don't show any lumps. I did send them a question about the polarity of the leads. They should get back to me in a day or two. I can't believe they didn't identify them. Not sure if I can get access to the LEDs. Everything seems sealed in a plastic case.
I did begin attaching leads to the latching relay. Boy are the pins on the relay small. Is it OK to solder to them? They look like they should go into some kind of circuit board that the leads would be attached to. Is there a better way to attach leads to the pins? This first turnout is just a practice one to learn the set up. If there is something I can plug all my latching relays into for the panel board that would make it a lot easier. So far though everything is working as you indicated it should. I could get addicted to this kind of project. Thanks for all your help. I could NEVER have figured any of this out for myself.
The pins are probably meant for circuit-board mounting. You might check out what Radio Shack has that might work with them, like this, for example: http://www.radioshack.com/product/index.jsp?productId=2102845&filterName=Type&filterValue=Breadboards
I would probably just solder directly to them.
lionelsoniI would probably just solder directly to them.
I'll solder them. Give me some good practice. As soon as I figure out the LEDs I'll be done.
The turnout works much better with this DC circuit. With track power they were very sluggish.
I thought of an experiment that might sort out the LEDs for you: The problem with just trying them out on 12 volts is that they can stand 5 volts of reverse voltage, but not much more. But red and green LEDs, unlike blue and white ones, need only a couple of volts of forward voltage to start to light up. So, get yourself three 1.5-volt dry cells (any size) and connect them in series (as they would be in a three-cell flashlight) to make a 4.5-volt DC supply. Connect an LED to that to see which way it lights up. The end of each cell with the nub on it is the positive terminal. The LED won't be very bright; but I think you'll see some light.
By the way, since there are no lumps in the wires in the vendor's picture, I think the ballast resistor must be inside the plastic case, which means that the lump in your wire may after all be a diode to protect the LED from reverse voltage. Maybe.
He could use an ohmmeter, if its battery is no more than 5 volts. (I wouldn't risk more than that, even with a ballast resistor in the circuit.) However, the trick is knowing which ohmmeter lead is which. I have seen them with both polarities. Unless he has another voltmeter to check the ohmmeter or a spare diode to compare with the LED, he still won't know which end is up.
Everything is working. Your suggestion of using the 3 batteries to check LED polarity worked like a charm. I have finished one turnout and it works perfectley. I love how the latching relay holds its position even when the power is turned off and when it is turned on again the correct indicator light is on. Now all I have to do is finish my layout and build a control panel. Thanks so much. This has been a great project.
GOOD JOB! I'd check this thread a couple times a day for updates. Once I'm done with a current project, I'll start on my turnouts.
Congratulations! It was a pleasure helping you with this.
I'm curious: Did the red wire on the LED turn out to be the positive one?
lionelsoniCongratulations! It was a pleasure helping you with this. I'm curious: Did the red wire on the LED turn out to be the positive one?
Yes, the red lead was positive and I had no trouble finding out which pin on the relay to attach each LED so that I got a green light when the turnout was in the straight position and a red light for the curved track. Watch for an email from me about a write up I am working on for this project.
Thanks Bob for all your technical advise and patience with me to get this right. Also thanks to all others who added their valuable advice and comments.
balidasGOOD JOB! I'd check this thread a couple times a day for updates. Once I'm done with a current project, I'll start on my turnouts.
Bob gets all the credit. I only bought some inexpensive parts and stumbled through his instructions to put one turnout together as a sample project. I would like to write this up to eliminate all my mistakes, add some pictures and a wiring diagram so it will be a clear and concise procedure, and either post it here or submit it to CTT as an article (after Bob has checked it for accuracy and with his permission). I think this is a fantastic way to operate turnouts and make a very efficient control panel.
Sounds good to me!
Some afterthoughts:
It may not have been obvious that the same DC supplies will be used for all the turnouts on the layout--you don't need separate supplies for each turnout.
If you design your own LED indicators, you can arrange to power them from the same supply that you use to charge the capacitors.
You can power related turnouts from a single capacitor-lamp circuit. For example, the two turnouts of a crossover are always thrown together; so they might as well have a single control switch. The circuit we used here will usually have enough charge to do that; but, if not, you can increase the capacitance, perhaps by paralleling a second capacitor with the first one.
You can use a power resistor in place of the lamp; but it doesn't fully charge the capacitor as fast as the lamp does. As the capacitor charges, the charging rate drops using either a resistor or a lamp. But, as the lamp dims, its resistance drops, partially compensating for the reduced voltage difference between the capacitor and the supply.
I like to use the lamp in some lighted accessory for this purpose. For example, I have several lighted bumpers wired into the capacitive-discharge circuits of nearby turnouts. To isolate them from the track, I just mount them on a very short piece of track at the end of the siding, isolated by gaps from the rest of the siding track.
Don't forget the stud-and-probe scheme I touted earlier. It's a good way to make a control-panel map more compact.
You don't have to use green for the straight path and red for the curve. On a prototype railroad, the red really indicates the diverging path. Although they almost always make the diverging path curved, on a toy-train layout, for lack of space, we often need to do it the other way; so on a control panel, you might want to use red for a diverging path, even if it is straight.
lionelsoniThe pins are probably meant for circuit-board mounting. You might check out what Radio Shack has that might work with them,
I found this breadboard at Radio Shack. I think it will work for connecting to the relays and will save on a lot of messy wires and soldering.
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