Turnout with feedback | ||||
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There are many (expensive) ways to control turnouts. My method costs less than 3 euro for each turnout. Märklin's control unit with feedback costs 22 euro for 4 turnouts, that's 5.5 euro each and you still have a poor overview over the actual positions of the turnouts. You can easily make a control board with track plan and feedback yourself. Märklin's electric turnout mechanisms has power cut-off in the outer positions. This is used to make the feedback. The feedback means that the control board will reflect the actual setting for the turnouts, even if they are operated manually. You need some switches with resting position only in the middle. They are usually named (on)-off-(on). I personally find it most logically if the LEDs are green and indicate the direction the train will drive, i.e. the opposite position of the turnout. The LEDs can be common (cheap) 3mm. The resistor should be 1-2KOhm (you just need it to indicate a direction, not illuminate the room!). You only need 1 resistor as the two LEDs is never lit at the same time. Don't use digital power for the turnouts. Use an auxiliary power-adapter. Any will do as long as it can deliver 15 - 18 volt DC 1,5 Ampere. You can also use a Märklin traffo (not the old blue). It's delivering pulsating DC, so it makes a bit more noise. The power supply dosn't need to be able to supply all your turnouts, as you normally only activate one at a time. Put a 100nF (nano farad) capacitor between + and - on the power supply. Coils, like in the turnout mechanisms, emit a short spike of high voltage. The capacitor short circuit these spikes so that they doesn't harm your LEDs. | |||