Signals for HO switch position

Model Railroader Electronics and DCC
1

Does anyone have any info on how to create and/or wire up LED’s to show the position of a switch? I am using Atlas code 83 track with their small remote #584 & 585 switch machines. I am using the MTH DCS system to power tracks but the switch machine will be powered with AC using the Atlas pushbutton momentary controllers.

Thanks so much for any info.

John

2

I use mini latching relays paralleling the Atlas switch machine coils. I haven’t run into any low cost AC latching relays so a simple diode in series with each relay coil works great if you are powering your switch machines from AC.

I watch for good pricing on eBay ($1-$2) for “DS2E-ML2 latching relay”. There are several voltages available, I buy the DC 5 volt coils and use a 100Ω resistor in series with the coils for 12 volt operation.

I don’t like to solder to the small relay leads so I use 16 pin DIP sockets.

EDIT:

3

That’s the way to do it. Unless you want to build (or buy expensive commercial versions) some specialized circuits to drive the switch motors. Atlas Snap Relays also work the same way, but these latching relays are cheaper.

–Randy

4

Mel,

Thanks so much for the reply. Since I am a novice but willing to tackle anything and have good soldering skills, are you willing to give me some type of diagram for using the diodes instead of the latching relays?

I would be great if you could.

thanks

John

5

I think you misunderstood - the diodes are used WITH the relays, there’s no way to indicate switch position with Atlas momentary action switch machines without some sort of latching contact.

CHeck out the Atlas Snap Relay. It’s more expensive but you may find it easier. It has 3 terminals like the switch machines and hooks up in parallel so the snap relay activates when the switch machine does. There are then 6 other contacts at the other end which work as a pair of switches which can be used to control the signal lights. The instructions include a wiring diagram.

–Randy

6

John

I’ll work up a drawing of how to use the latching relays with pictures. It isn’t complicated and if you use sockets you won’t have to worry about dinging a relay with the soldering iron.

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

My Model Railroad

7

Here is how I wired my latching relays.

  1. I went to 5 volt coils on my latching relays to maintain interchangeability with my control system and because they are much cheaper than 12 volt relays.
  2. I use sockets one everything to simplify maintenance, no soldering or unsoldering to swap parts.

This is a dual coil latching relay.

Pins are numbered from 1 through 16, there are no #5, #7, #10 or #12 pins on the relay. The relay will plug into a standard 16 pin IC (Integrated

8

Check the thread ‘Photoelectric Switch’ You could use this switch for you lights. On one side of the throw bar is the switch machine. On the other side of the switch the throw bar moves in and out from the rails. Putting the photo eye under the throw bar so the throw covers and uncovers the photo eye would switch you lights. On the photo switch the screw termial block has a common connection on the center screw. One of the other screws is normally closed and the third screw is normally open. By attaching one led to the normally open contact, and the other to the normally closed, the leds would turn on and off when the switch moved. Don’t forget the resisters for the leds.

Read all the reviews for more detail of this Photoelectric switch.

Mel found some on ebay for a great price.

9

Mel, Thanks so much for taking the time to help. At least I can start planning. With your design, will I have to manually unlacth the realy to change the LED color?

I wnt to your wbsite and what you have done with simple electonics components anodds and ends is totaly amazing!!

Regards,

John

10

Sounth Penn,

Thanks for your idea. It is amazing how many people on this Forum site are so helpful to nebies like me who are starting in the HO hobby.

Thanks again ,

John

11

John I’m not sure what you are asking. Once you wire the relay coils parallel to the Atlas switch machine (don’t forget the resistor and diode) the relay contacts center common pin 6 will switch between pin 4 and pin 8 automatically when you operate the turnout.
The green LED connected to pin 4 will illuminate with the relay “unlatched” and the relay contact pin 8 will illuminate the red LED when the relay is “set” when you turn the points of your turnout.

If you need help IM me with your phone number and I’ll give you a call.

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

12

I wonder if he can see your drawings - there is some sort of issue with Photobucket right now, what I get if I try to open the link (just show as an X for me) is a picture of a kitten that says “hang in there - we’re having some problems but will be back soon”

I like that banana plug adapter you did to get measurements on circuits. I need to make one of those. BTW you don’t really need to saw those header pins, grip with a needle nose pliers next to where you want to snap a group off and snap, it’s already scored but it’s like scoring and snapping styrene.

–Randy

13

Randy

It just must be me but every time I try to break them off they break off at a contact and I loose a pin.

Every time I need a squirrely adapter I make a couple of them, I’ve got a 4” x 6” drawer full of my squirrely adapters.

I’ve gone exclusively to the micro connectors, it sure makes working on stuff a lot easier having compatible connectors on everything.

I made a bunch of Arduino to Micro connectors and that took care of a lot of problems caused by test clips.

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

14

John

Here is a working link, Photo Bucket is down for maintenance


https://drive.google.com/open?id=0B7gZp9MPvrm3dm9yYWFNMEZZNlU

Photo Bucket is finally up

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

15

John,

Here are a couple of pic’s of the Atlas relay instructions, should You want to go that route. I used them on My layout that was started back in 1980 and have 45 of them installed for control panel lights, switch signals and to power the frogs. Have not had to replace any of them in all those yrs. I use under table machines and normally open push buttons on control panel instead of the Atlas switch controllers. I got the relays in bulk, back when they were 7 dollars a piece though. I use a seperate 3amp. 12VDC supply for the lights.

Take Care! [:D]

Frank

16

Mel,

Thanks for the reply. I am trying to locate a good price for the latching realys you specified. AM I right in thinking I need 2 of the relays for each of my switch motors? When I get what I need, I may need to contact you again for help but you said to send you an IM but in my old age, I don’t know what that means. I guess I am having an ALEPO moment. Many thanks again.

Regards,

John

17

John

You only need one relay per turnout.

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

18

Mel,

Thanks for the heads up on the email address. I’ve taken care of it.

John