| Author |
 Topic  |
|
CSX Robert
USA
439 Posts |
 Posted - 11/06/2009 : 18:39:05
|
In the past I've seen several posts from people requesting circuits to indicate the position of turnouts, so I thought I would share what I have come up with. I originally developed these working with Kato Unitrack turnouts, but they will work with any turnout that has a live frog that switches polarity with the turnout and/or is power routing. These circuits light one of two LEDs depending on which route for which the turnout is set.
The first circuit works with a live frog:
(I did not include resistor values because that will depend on your track voltage, selection of LEDs, and how bright you want the LEDs.)
The second circuit works with power routing turnouts(you double the circuit and put one on each leg of the turnout):
Some advantages to these circuits are they work with DC and DCC and they are independent from the method of turnout control. Being independent from the turnout control is especially nice on turnouts like Kato's because the LEDs will match the turnout whether you throw it remotely or by using the slide on the side of the turnout.
Some disadvantages are on DC, the circuit only lights when power is applied, and brightness varies with the amount of power(although in my experiments, if there was enough power to make an engine move, I could easily see which LED was lit). Also, the version for a live frog can be hard to wire, for example, on a Kato #6 turnout you would have to open the bottom of the turnout to wire it to the frog.
Another neat feature is on Kato turnouts you could have the diodes and resistors in the roadbed and the LED's coming through to the top, made into a signal even, so that you could have the turnout and indicator in one self-contained unit.
Let me know what you think about it! |
|
|
GOLDENSPIKE
USA
1138 Posts |
Posted - 11/06/2009 : 21:06:09
|
| I just use the extra contact switches provided on Tortise switch machines to light up a track signal. No light means the main line is selected. Light means the turnout is thrown to enter the siding. (this is on the mainline of course).[:-bigeyes] |
Ron S.
"How many model trains is enough ??...a few more."
(a take on a J.D. Rockafeller quote.)
|
 |
|
|
jagged ben
615 Posts |
Posted - 11/06/2009 : 21:15:01
|
For those using Tortoise or similar machines, here's a nice little circuit that hooks up to one of the poles on the Tortoise. It does require it's own separate AC power source. (12 volts is good.)
The bi-color LEDs can go either on your panel, or a two aspect signal, or two single aspect signals, or all three in parallel. It's quite handy.
One nice thing about this circuit is that, being totally independent of the method of turnout control, you can use any control method you like, and even change it while not redoing the indicators. It also gives a positive indication of whether the turnout has actually thrown.
EDIT: image now updated for clarity
 |
Edited by - jagged ben on 11/07/2009 16:26:36 |
|
|
|
peteski
USA
1667 Posts |
Posted - 11/06/2009 : 21:39:44
|
| Ben I might be nitpicking here but your bi-color LED is not drawn correctly. As it is drawn now (LEDs in series) it'll never conduct current (or light up). The LEDs inside the bi-color LED are wired in reverse but parallel. |
Peteski |
|
|
|
PGE_Modeller
Canada
137 Posts |
Posted - 11/06/2009 : 22:31:15
|
If you put the bi-colour LED in series with the motor of the Tortoise, you don't need any of the other components. The motor of the Tortoise functions as the current-limiting resistor, the additional diodes are definitely not needed, and you have both sets of SPDT contacts available for other uses. I use one set to control the frog polarity and the other set to control "stopping sections" that prevent a locomotive from running onto a frog of the wrong polarity.
Cheers, |
 |
|
|
|
peteski
USA
1667 Posts |
Posted - 11/06/2009 : 23:51:23
|
| Yup, that works too and it is very simple. Friend of mine uses similar of circuit except he uses DC power which is routed through a polarity-switching DPDT toggle switch mounted on the control panel and 2 discrete LEDS (instead a bi-color one) placed on the track diagram to indicate the route. |
Peteski |
|
|
|
steve turner
4045 Posts |
Posted - 11/07/2009 : 00:52:16
|
Heres one easy to follow. Good for Tortise LEDS work only one way so note the short and long legs of the LEDS. Dare say you could make a bi polar LED work this way to. Im going to use the toggle as i want to use switches on Tortise for signal lights.
http://www.sierrascalemodels.com/Art_Lighted.htm |
|
|
|
peteski
USA
1667 Posts |
Posted - 11/07/2009 : 00:58:10
|
| That is the exact circuit my friend uses(the 1Kohm resistor is replaced by the Tortoise motor of course). We use 12V. What is nice about this circuit is that the LED gives you positive indication of then the machine finishes the throw. The LED dims during movement of the points and it glows brighter when the motor stalls. |
Peteski |
|
|
|
PGE_Modeller
Canada
137 Posts |
Posted - 11/07/2009 : 03:29:40
|
Here are two ways of doing this: one uses dual power supplies and SPDT switches, the other uses a single power supply and DPDT switches. The LEDs can be individual ones or bi-colour ones and, as Peteski says, the Tortoise motor functions as the current-limiting resistor so the only components are the power supply(ies), the LEDs, the switch and the Tortoise itself.
Cheers, |
|
|
|
|
jagged ben
615 Posts |
Posted - 11/07/2009 : 15:48:38
|
quote:
Originally posted by peteski
Ben I might be nitpicking here but your bi-color LED is not drawn correctly. As it is drawn now (LEDs in series) it'll never conduct current (or light up). The LEDs inside the bi-color LED are wired in reverse but parallel.
Sorry for trying to cut corners on the drawing. I've updated it, and it should be less ambigous now. |
Edited by - jagged ben on 11/07/2009 16:09:28 |
|
|
|
jagged ben
615 Posts |
Posted - 11/07/2009 : 16:21:35
|
quote:
Originally posted by PGE_Modeller
Here are two ways of doing this: one uses dual power supplies and SPDT switches, the other uses a single power supply and DPDT switches. The LEDs can be individual ones or bi-colour ones and, as Peteski says, the Tortoise motor functions as the current-limiting resistor so the only components are the power supply(ies), the LEDs, the switch and the Tortoise itself.
Cheers,
For either of these methods, if you use bi-color LEDS, you could put another bi-color LED in the opposite direction in series, to use for the other track. |
|
|
|
oldbill_indy
USA
929 Posts |
Posted - 11/07/2009 : 16:46:54
|
| I'm glad that I am control dumb and simply wired my bicolor red and green LED's of my Tortoise turnpouts in my control panel using a seperate 12V power supply. When I throw the panel switch, the LED will indicate red or green depending on the turnaout direction. Easy and never fails. A resistor of about 760 ohms was soldered to each LED to limit current. The only electronics I remember from 1950 Navy training was the infamous half wave rectum fryer! |
VICTOR DESERVES HIS ATLANTIC BECAUSE I SAY SO!
My Layout Looks Pretty Good From 100 ft!
All men are not created equal and that is why I need a good repair service or Victor! |
|
|
|
BillPearce
331 Posts |
Posted - 11/07/2009 : 19:50:21
|
Greg,
Perfect! I have dozens just like that on my layout, and they work perfectly! Just another advantage to using the Tortoise.
Bill Pearce |
|
|
|
PGE_Modeller
Canada
137 Posts |
Posted - 11/08/2009 : 00:34:31
|
quote:
Originally posted by BillPearce
Greg,
Perfect! I have dozens just like that on my layout, and they work perfectly! Just another advantage to using the Tortoise.
Bill Pearce
Hi Bill,
I suspect there is a point at which the cost of two power supplies and SPDT switches becomes less than the cost of a single power supply and DPDT switches, but I certainly didn't reach it with the 13 Tortoises I have in my staging yard. All the other turnouts are operated by push rods. The wiring is also simpler (i.e. doesn't take as long to do) for the two power supply version as you don't need to add the cross wires to all the DPDT switches.
Cheers, |
|
|
|
|
BillPearce
331 Posts |
Posted - 11/08/2009 : 10:25:08
|
I suspect there is a point at which the cost of two power supplies and SPDT switches becomes less than the cost of a single power supply and DPDT switches, but I certainly didn't reach it with the 13 Tortoises I have in my staging yard.
I certainly didn't reach that in the fifty or so that I have, but I got my switches from a discount and close out supplier in LA so price wasn't that hugh a factor. Switches can be expensive in small quantities.
Bill Pearce |
|
|
|
peteski
USA
1667 Posts |
Posted - 11/08/2009 : 19:07:48
|
We use single 12V 2A power supply with DPDT switches but had so many switch machines on the layout that we ended up buying another supply and splitting the load. Those were unfiltered DC supplies and when the layout room was quiet you could hear the 120Hz hum from all the switch machine motors. That annoyed me so I added filter capacitors to filter the DC voltage which eliminated the hum.
BTW, the types of power supplies needed for this (large wall-wart types) can be had for less than a cost of single switch machine. Lots of electronic surplus websites carry such supplies. |
Peteski |
|
|
|
Topic |
|
Topic Locked
