Excellent feedback, Jim. I was going to suggest a 1k ohm resistor but nice to see some tested results. I would also avoid using a bi-color LED, though a tri-color would work nicely if you can find some cheap enough. Personally though, I prefer using two LEDs arranged accordingly on the track diagram to make it obvious at a glance which way the switch is set. I'll be using a slightly modified version of this to run my Atlas switch machines (modified appropriately for the dual-coils, of course). I'll post that diagram later. EDIT: Noticed one more thing on my version of the circuit diagram. Using a center-off DPDT isn't necessary, but it can allow for cutting out a switch for live repairs to lights, etc. Either will work though.
The advantage of my design is that you can power blocks of switches with a single push button like a CTC machine. Resetting any manually changed switches in an entire section an be accomplished by pushing one button, if wired that way. The drawback to your version is that it needs a push button and toggle for every turnout. The Bi-Polar LED problem can be fixed by switching the polarity of the connections. The lighting components are not dependent on the polarity of the switch wiring.
There is a problem with this circuit. The green LED's anode is always connected to the positive voltage through the resistor and it's cathode is always connected to the negative voltage- the LED will be on no matter which position the switch is in. Conversely the red LED's anode and cathode are both connected to the positive side of the 12v supply - the LED will never light. To get this circuit to work hook one of the cathodes to each of the center terminals of the switch.
Good point. I agree that it would be an advantage that it would reset any switches so that they'll match what's represented on the board. But what if you've overridden a switch position manually at the switch? Then, of course, the board would be showing the wrong position, which could lead to its own problems. And how much more current would it be drawing if you're powering 25 switches compared to just one? Or 50 switches? (I'm asking seriously, I don't know how much current the Kato switch machine draws.) And now that I've fixed my diagram, it seems pretty clear that using a bi-color LED would be super easy across the center connections of the dpdt switch, as long as the bias resistor was in there, of course. Good point.
Something just occurred to me. If you've got X number of switches, all controlled by a single momentary contact pushbutton switch, what happens if the switch fails? Specifically what if the switch fails closed? It would seem to me that you'd have X number of melted switch machines, right?
Replace the button the first sign of sticking. You should not be holding the button down. Unlike other manufacturers the Tomix and Kato switches are not dependent on current or amperage to throw the switch. They use magnetic polarity. I often use a single AA battery to test throw my Tomix switches. The power draw on the circuit would be driven by the demands of the LEDs. The problem of indicating the manually throw switch is not covered by the circuit, but would be fixed by the push of the button. The problem is the same on the real railroads.
I want to thank everyone for their help on this. Side track, I was on vacation the last 2 weeks with my son so first chance to respond to any one. Back on main, as I was saying thank you everyone in helping me with this dilemma, the final verdict that I have hooked up came from George Stiwell his schematic works great and I am using one red and one green LED instead of the bicolor led and it looks cool...can't wait till I get everything hooked up so I can shar some picturs.So thanks again everyone, when I come across another dilema I will always ask.Dave
Someone posted about indicator LEDs for Kato turnouts on another forum and it reminded me that I never answered the following question: I assume this post was directed toward me since it directly followed my post. I read the post and went back later to answer and the site was down for the upgrade. Anyway, hopefully better late than never, I do not have a diagram, but I do have some pictures: Some pictures of the circuit in a turnout:
And some pictures of it oerating(I plan to make a dwarf signal out of the LEDs, but they are currently just hanging by their wires):
If you can use a Bi-Color LED check this design out. http://www.trainboard.com/grapevine/album.php?albumid=1448 The LED is a 3mm one The Brass tube has a OD of 2mm.
Please explain what the Atlas device is for. If these were three wire switch motors, I'd understand. But the two wire Kato switch motors use a positive or negative magnetic pulse to move a magnet. The Atlas motors use two separate coils to drag a iron slug from side to side.
After reading all of this I'm very glad I went with Peco C55 turnouts where all I need is a set of contacts connected mechanically to the throw rod so that when the switch is thrown the appropriate contacts are thrown too. Nice and simple.
