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Please post a link to the relay product page or data sheet.
Any voltage source with the proper level to light up the input LED of the optocoupler, can be used to trigger the relay.
I would call that unit a "relay module", not just "relay". In the lamp circuit You can preferably change VCC to Vdd. Vdd can be of any kind, AC as well as DC. The only demand is being less then the spec for the relay, 205 Volt AC or 30 Volt DC.
I've got a few. They draw very little current from Vcc and the signal point can be connected directly to an Arduino output.
I would give some thought to using hall effect sensors at your "different track locations". (or an optical device for that matter)
There would be some metal somewhere on your train that could trigger the hall switch.
Hall switches will detect metal by placing a small magnet on the rear side of the hall effect sensor( google will tell you how)
- It would give the Arduino definite locations so it could switch on the correct colours.
- It would be completely independant of your train supply if required.(probably best)
- You could still use your purchased relay module for 1 large load if required, otherwise simply use small 2n7000 mosfets as switching elements for the LEDs. (much smaller and less cost)
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Vcc is a very usual designation for the controller voltage, either 5.0 volt or 3.3. Vdd is a common name for "other" voltages, mostly higher voltages. As the logic part, the Vcc part is galvanically separated from the Vdd circuit it is possible, even an advantage to not use common GNDs. That keeps eventual electrical "Vdd-noice" at a grater distance from the sensitive Vcc-circuitry.
I will be dropping one down to 3.2v for the LED's
This sounds strange to me because LEDs are current controlled, not voltage controlled. Make a little wiring to show what You think of.
Vcc and Vdd both stand for circuit power supply voltage applied to collectors or drains of transistors, and these days, is usually positive (cc = collector for NPN bipolar transistors, dd = drain for N-channel MOSFET transistors). You will also encounter Vee and Vss, emitter and source voltage connection (often but not always GND).
I will be dropping one down to 3.2v for the LED's
You don't need to do that for LEDs, but a correctly chosen current limiting resistor is required in any case.
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Don't expect the LEDs to last long, if the current is above maximum specification.
tobinibi:
I am using step down transformers so I don't have to use resistors at each LED and to help reduce heat and allow me to hide things easily. I am able to run alot of LED's off of 1 transformer.
You are way out of knowledge. You're totally wrong. It's sad Your text is not erased by moderator.