I am building a DC layout and learning the electonics on the fly. I have a number of insulated sidings that will be hooked up to my control panel. I would like to add an LED lamp (red/green) to show the siding is powered or not. Instead of using the track power to power up the LED, I would rather hook up a separate DC power source so the LED is always on, even if the siding is not live. Is there a specific type of switch that will allow me to control to functions with independant power sources and any wiring advice would greatfully appreciated.
Well, to cut power in a siding you only need to insulate one rail, so what you would want is a double pole double throw switch (DPDT). Probbaly one WITHOUT a center-off position. One pole is used to apply power to the insulated siding. The other pole is then free to use an independent power source to light an LED. If you really want you can wire up a red/green LED, but a green LED that shuts off when the power is off is probably sufficient. For the red/green LED, the wiring is a little more complex. The diagrams posted for hooking one up to Tortoise contacts is what you want, with the switch substituting for the Tortoise contacts.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thank you for the quick response Randy. I will give your suggestion a try.
Be careful of which R/G LED you select. To wire it to the DPDT toggle, make sure you get 3-lead LEDs. These have a common lead and one lead each for the red and green sides. You can also buy 2-lead R/G LEDs, but they will be red or green depending on the polarity of the voltage across them. These are sometimes wired in series with the drive power for a Tortoise, but are not what you want for your application.
Just noticed your post count. Welcome aboard!
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Shows how MY brain works .... this is what came to mind when I saw the topic title ....
Why would you want to light your siding with LEDs ?
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
AC power, 2 little regular diodes, and a 2-lead bicolor LED would work just fine.
Or a bipolar DC supply, and no extras.
You want to know if the power is on or off? For whatever reason, it is as easy as pie. If the switch is lined to your track the tally light is on, if the switch is not lined for your track, the light is off. Track power is controlled by the switch machine.
Now if you connect one side of your Tortoise to Ground, then + = normal; and - = reversed (or aligned to the track in question). A Bi Color LED will tell you if the switch is normal (no power) or reversed (powered).
On layout of LION, there are no controls to turn power on or off of siding tracks, the turnout does that. On layout of LION the position of the interlocking lever tells the tail.
What LION does have is detectors to indicate that a track is occupied by a train or not regardless how the switch is lined. In answer to another poster, the LION pontificated on train detection. LIONS uses reed switches, magnets and relays to detect the presence of a train. On some tracks, him uses a FEATHER. A lot less wiring to use a feather, but trains cannot back up easily against the feather. Him uses it only on through pockets (which are in a very difficult place to work on.)
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS