How to build a miniature fastrack switch machine controller

Well this will start a big argument but here goes.

Wait for the Ipod app...

Well, the indicator light feed is bi-polar 5V, so having a bi-polar red/green LED will make this pretty easy.  You could do it as simple as a bi-color LED and a resistor (the actual indicator voltage measures out at about 5.3 volts on the one I tried.  The LED and resistor go between the ground wire and the indicator wire from the switch. 

Of course, if you insist on having separate LED's, you can wire two, a red and a green with their positive and negative terminals swapped so they're polarity sensitive.  Add the same resistor, and you're home free.  I'd use between a 150 ohm and 220 ohm resistor in either case.

The switch just pulls the respective control to ground to do the switching.

The bi-color LED would be fine, although separating the red and green lights would allow the light to be placed on the track that is aligned to the switch. What do others with control pannels do here, is there two lights or one light on the track layout drawing for a switch?

I want to stay away from compute control, although an Ipad app may allow for touch screen control, instead of a hard wired control pannel. The advantage to a hard wired control pannel is it is easy to understand and operate, although more difficult to build. I also have a separate control pannel for each town, so that 3 people can work the layout at the same time.

Thanks for your help. I will have to build a prototype to test my understanding of the concept.

ThanksL Joe K

One or two lights is pretty much the same effort, so either one works.  I've seen them done both ways, dealer's choice.