Baby Deltic is correct in his statement about programmable or microcontroller regarding intelligent logic........ However in my case that was not actually what I meant.
Our layout has twin controllers, each of which is capable of being used for any section on the layout. Eg. Section switch is up, the panel mounted controller is active, section switch is down, and the 'walkabout' controller is active........centre off and the section is dead.
When this layout goes to exhibitions my parents receive help from a variety of people, and to be honest it is not the easiest of layouts to operate for someone who is unfamiliar with it.
The main motivation was a practical one to make operation easier, however I have long wanted to see lights on the panel .
My criteria for this was to indicate using bi-colour Led's which controller was active for any particular section and also which route was set. There are many ways to do this type of thing, however since the layout wiring is already complete, I decided all necessary wiring would be contained in the panel and not interact directly with the layout. Further more as has been mentioned elsewhere, it is possible to use the switch on many pointmotors to drive LEDs/BULBS, but the points on Pfaffenbrucke are 'Live frog' as such that was not an option for me.
When the panel was initially built, I had various ideas for the future about diffent things i would like to do with lights, so it was already decided that section switches would be double pole - double throw - centre off (DPDT) from the beginning.
I am not sure how far to go into detail on this, or if this is the correct thread for it? But I will give short form theory behind how I have done it on our layout. If You wish to PM me, I can elabborate in quite extensive detail if you wish.....
Let me show you first how to achieve Red/Green from 1 switch per section. If you just have a single controller, this might be suitable to indicate ON/OFF for example, but in our case it is used to indicate the active controller.
That is all that would be necessary for plain track without points.......
Since most layouts have points........This is how I indicate the point direction AND active controller.
The theory is one bi-stable relay per point motor wired in parallel with the point motor. From the included picture, it can be seen LED 'A' is just a function of the position of the switch, LED 'A1' and 'A2' are a function of the position of the switch and also the direction of the point motor.
That is it in simple theory..........
I am not going to explain further here, but it does become a little more complex when cascading point motors.......
This is the general overview of what was needed for our layout.
Finally, here we see the finished circuit. Front centre is the +- 5V power supply for the LEDs, derived from a standard 16VAC transformer.
If you would like further informtion, PM me.
Graham