Anyone know of a source for momentary, position-indicating toggle or slide switches with the following logic, to be used to trigger twin-coil turnout motors and hold position indicating LEDs?
(ON)-ON-ON-(ON)
or
(ON)-ON-OFF-ON-(ON)
In either case, with toggle returning and remaining skewed in the ON position in the direction of the most recent momentary throw? In other words, a sort of mechanical latching.
Thx.
Hornby make one.
Their switches are shaped to be combined in something akin to a lever frame, but you could probably fit it into a cutout in the panel.
That looks like it fits the bill on the momentary "(ON)" aspect, remains visually set in one or the other direction, but does not appear to return and hold an "ON" condition. Or maybe it just isn't clear from the Hornby docs.
Why not use a toggle switch and a pushbutton?
The most elegant solution I've found are rotaries with spring returns
-- if I could find some reasonably priced. (I'd need 20.)
Cole 3600 series, p/n 3611 or 3608 rotaries would be ideal, for example.
A lot of us would like such a switch, but I have never seen any at a price point suitable for model railroading. The most straight forward solution uses twincoil machines with auxilary contacts to drive position indicating LEDs or lamps. Unfortunately the common Atlas snaptrack switch machine lacks the necessary aux contacts. For the Atlas machines I have used one of Peter Thorne's CD circuits from "Model Railroad Electronics" Kalmback Publishing MR handbook 37. The circuit uses two capacitors, six resistors and two SCR's. It will drive position indicating LEDs with ease. I built up several from scrap parts and they work well. Part values are not critical. The SCR's handle the heavy current from the capacitors to the coils, the control switch just carries the light SCR trigger current, which means low cost switches will last forever.
David Starr
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Rob Paisley's site might have some useful information:
Bill Bill's Railroad Empire N Scale Model Railroad:
Think outside the square (or rotary as the case may be).
Use a normal 4-position rotary. Call them 1, 2, 3 and 4 - no, the positions, not the switches! Wire 1 and 4 to your position LEDs, and 2 and 3 to your switch machines. Treat these ones (2 and 3) as passing contact. Just make sure you throw the switch all the way, in either direction.
Steve
Walthers used to sell a standard Cutler Hammer lever switch that did just that, they called it the "Toggle Key".
You'd have to peruse electronics catalogs to find it however, Try looking under "lever switches" or "Telephone switches". It's a style of switch that was used years ago in telephone switchboards.
Don
-- snipped-for-privacy@prodigy.net
If I were the only one operating, perhaps, but given how fragile those turnout coils can be, that looks like a recipe for disaster...
Maybe this was answered and I missed it: why not use one SPDT toggle switch plus one pushbutton, or (if continuous LED indication is desired) one DPDT toggle plus one pushbutton? Sure, it seems inelegant, but it meets the requirements, it's safe, and it's cheap.
Here is a specific link for toggle switch control of twin coil machines from my site.
Thanks, Rob (and other suggesters). I guess the answer is to do it electronically.
One further question: Do you have a rapid LED indicator turn-off circuit for the Atlas and similar twin-coils with no separate coil wiring?
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I have added 2 new circuits for Atlas and similar machines. In all cases an extra pole on the toggle switch can be used for frog polarity control.
Terrific! Many thanks, Rob.
- Bob
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