To turn on the LEDs corresponding to the position (direct = green, diverging = red) of each turnout, and not to have to add fragile and difficult to find micro contacts, I used the frog feeding microswitches. LEDs will therefore be powered by the DCC current.
In this diagram, the part framed in dashed lines is the actual turnout motor; the other components are external, and placed in the control panel. We see that only one additional wire is required, that which goes from the frog to the current limiting resistor common to the two LEDs. Normal diodes are used to protect the LEDs against reverse voltages (DCC current is alternating).
In the diagram position, I indicated in red the path of the current.