Wire LED indicator to on/off switch for isolated section

[Fozzy84]

Hello all,

 

I'll get the basics out of the way. Whilst doing my mum and dad's loft, I found my old train set which has probably been up there at least 25 years (I'm now 36). Long story short, fell in love again and serviced three locos and cleaned all the track with peco rubber and it works well... but I want more...

 

Fast forward a couple of months and I'm in the final stages of planning a 10ftx6ft layout in my loft and potentially a divorce. I have planned a three oval layout with a yard in the middle. There is then a station running off the outside line as well as a long siding of the outside too. All three ovals run off their own power supply and controller (4x R965) as does the yard in the middle. There are insulated rail joiners at the points and each point is connected to a point motor, which in turn, will be connected to a switch control panel.

 

I am running DC and know that whilst it is probably overkill and I'm not sure whether I will go to DCC in the future so, each track is connected direct to the power via soldered droppers and fed into a bus wire.

 

I'm a novice when it comes to electronics but I can follow instructions and have cut into the mains supply for power and lighting to the loft and rewired my kitchen before so I'm confident I can work with electronics. It's just diagrams and technical jargon goes way over my head. Resistors, ohms and all them squiggles and zig-zags... I will learn though and have found Brian Lambert's page particularly helpful so far.

 

To my query, the sidings and station run off the power supply and controller of the outside oval. There are IRJs at the connection between the points and beginning of the track for each To isolate them. Whilst the power comes from the same controller, it is not connected to the bus wire but is, instead, a separate cable, for each, coming from the controller which is connected to an on/off switch and then feeds into the track. When I have a loco in either and want it to be stationary, I will then terminate power to prevent it moving. 

 

Now, for no other reason than it will look pretty and I like the idea of it, I'd like an LED light (or even two (red/green) connected to the switch to give an indication of when it's live and ideally have this showing on my control panel.

 

So can I ask, how is that LED connected to the switch? Do I need a resistor? Will it cause any knock on voltage dropping by adding it? And if possible, can anyone point me in the direction of a very basic diagram to assist? 

 

Thanks in advance...

Chris

[RB51]

Hi Chris and welcome to the forum. Great first post which is always helpful. Our resident diagram expert will be along shortly [also a Chris] with your answer. Well, to your LED query anyway - not the divorce thing. 😎 R-

[Howbi]

A simple solution would a DPDT on-off-on switch..........the switch could be mounted north-south on your board so that in the down position allows current to the siding (LED off) and in the up position turns on the LED but cuts current to siding........the LEDs could be run off a 3 volt battery avoiding need for resistors.......

/media/tinymce_upload/3f11d1578e53a896721699e01b61a737.pngin this example, tag 3 to LED - tag 2 to 3v battery.......tag 5 to one side of your bus, tag 4 to matching rail on siding maintaining polarity.........HB

 

p.s. could even have another LED connected to tag 1 to light when track live so have one red LED & one green.

[96RAF]

If you use a bi colour (3-legged) led you could have green when siding is energised and red when it is dead. I have used dual red/green signals for each junction to show red if the point is set against the  road or green if the point is set for the road. Hence red+green showing or green+red showing.

 

This shows them in use on track but the leds could equally well be on a remote mimic panel. The leds are controlled by a switch on the point motor so the indication seen is that of the point position not the mimic panel switch selection.

/media/tinymce_upload/0328a7dfde192889eca14190b234459f.PNG

[Chrissaf]

Taking a salient point from your text.

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The point motors exist and have already been fitted and are working.

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Now you haven't told us what type or brand of point motor you are using. You also haven't told us what power supply you are using to operate the points and you haven't told us whether you are using a CDU or not. Despite your detailed post description in other respects, it is the point motor details listed above that are the most importantly needed bits of lacking information.

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So in the absence of confirmed details, this reply assumes Hornby track and Hornby Solenoid point motors.

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Now given that the motors are already installed and in-situ and working and also given that if Hornby branded that they are not the easiest motors to retrospectively fit change-over contact switches to. Then my recommendation would be to use GaugeMaster GM500D latching relay boards.

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These are the reasons for this recommendation:

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1. The GM500D are DCC friendly, thus they give the upgrade path to DCC that you have intimated might be on the cards in the future. The GM500D is 'positive common' which matches the bulk of DCC Accessory Decoders on the market. It is that which makes the GM500D DCC friendly. So if your existing point motor wiring has been wired as 'common negative' it is an easy task to swap over the positive and negative output of the power supply being used to operate the current points if DC. If the power supply is AC and not DC, then AC is natively compatible with the GM500D and won't need any modification.
2. The GM500D uses the existing point motor wiring and is just teed into the 3 wires currently connected to the point motor in parallel. Thus they are very easy to install and configure.

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In the GaugeMaster supplied schematic below, it shows a 2 aspect signal. This signal can be replaced by a pair of LEDs to indicate point position on a mimic panel. LEDs must always be protected against excess current. The easiest way to do this is with a resistor. Note that a resistor is not shown in the schematic below. A resistor should always be used even if using a 3 volt supply as HB suggested. Not all LEDs operate on 3 volts, the voltage varies with LED colour.

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/media/tinymce_upload/28e38c1696ed6dcf84aa48587636946c.jpg

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The above schematic is an 'in principle' one. I am quite prepared to produce a custom schematic specifically for your solution, but I need the answers to the questions I raised earlier regarding point motor detail. Else I do not know the exact solution I need to design for.

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Ignore the Accessory Decoder shown in the schematic above. As I said the GM500D model is meant for DCC. It will be just as happy working on a DC Analogue point controlled layout. This is why you need my services to draw you a 'custom' schematic wiring diagram.

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To recap, the information I need to produce a custom solution schematic for using the GM500D relay is:

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1. What is the point motor operating power supply being used?
2. Is the power supply a DC or AC output?
3. What is the voltage and current specification of the power supply?
4. Is a CDU (Capacitor Discharge Unit) being used?
5. Are the point motors 3 wire Solenoids (i.e Hornby R8014 / R8243, PECO PL10 or SEEP etc)?
6. What switches are being used to operate the points, are they Hornby R044, PECO PL26 or centre off sprung toggles or something else completely (if so what)?

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TIP: As this is a relative newbie post, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

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Particularly as my reply includes an image. If you use the blue button, any reply you write, may be held back for image approval. Even though it is already a previously published image.

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See also – further TIPs on how to get the best user experience from this forum.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

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[Fozzy84]

Thank you for taking the time to reply RAF96 and Howbiman, you have given me some ideas there.

 

Chris... again, thank you for your time and forgive the lack of detail, I will answer your questions below. As said in my post, I am in the planning phase so although I have bought pretty much everything so far, nothing is set in stone and no track has been laid... that said, it is all Hornby track and the points are all insufrog type.

 

1) I am using an old Dell laptop charger to supply the point motors.

2) It is DC output

3) It is 19V attached a picture in a separate post 

4) I have a CDU which can be found here https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F400583931383

5) The point motors are Gaugemaster PM-2 Standard

6) And the switches are on/off/on toggle switches of which I have a box of single pole and double too. 

Hope this helps. If there is anything else that needs clarifying please let me know. 

Thanks

Chris

[Fozzy84]

Apologies can't upload the image... it's this one though 

https://www.3cparts.co.uk/original-608428002-hp-74mm-50mm-90w-chargeradapter-p-31450.html?gclid=EAIaIQobChMIpr6r3Mzo5wIVR7TtCh0GHQbzEAQYASABEgLrzvD_BwE

[Chrissaf]

I should stress that Part 1 of this post reply is offering a solution to indicate on the point operating switch panel the position of the points. That is to say whether the points are routed to the left or routed to the right. A simple LED indicator for showing whether the track has live power on it or not is shown in Part 2 of this reply. An enhanced track power indicator version is shown in Part 3.

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I am of the opinion that the Part 1 LED point position indicator is a more useful feature to have than a general track 'power on' indicator.

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Part 1

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Thank you for coming back and answering all my supplementary questions in detail. I now have enough information to give you a definitive solution schematic on the basis that you adopt my GaugeMaster GM500D solution to supplement the GaugeMaster PM-2 point motors.

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Note...if you haven't purchased the GaugeMaster PM2 point motors yet, then purchase the GaugeMaster PM1 (or PM4) point motors instead. The PM1 (or PM4) point motors have integral SPDT change-over contacts directly on the point motor itself. This would mean that the GM500D can be eliminated and the integrated PM1 (or PM4) change-over contacts can then be used to replace the functionality of the GM500D relay contacts to operate the mimic panel LEDs instead.

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If the wrong LED lights up on the mimic panel when operating the point, then just reverse the wires on Pins 5 & 6 on the GM500D (or terminals D & E on the PM1 (or PM4) point motor if using that option instead).

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Both the PM1 and the PM4 have the integrated change-over switches. The difference between the two is that the PM4 has an additional locking spring (latching action) for use with points that have lost their own integrated locking spring.

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/media/tinymce_upload/bc368847d8b6de736c26af0eb11d6c4b.jpg

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Changes to the above schematic if the GM PM1 (or PM4) point motor is used instead of the GM500D.

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• Obviously the GM500D is deleted from the schematic.
• The wire shown on Pin 4 of the GM500D would connect to Terminal F of the PM1 (or PM4)
• The wire shown on Pin 5 of the GM500D would connect to Terminal E of the PM1 (or PM4)
• The wire shown on Pin 6 of the GM500D would connect to Terminal D of the PM1 (or PM4)

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/media/tinymce_upload/2d2b311d9a0c2695182d69467d78d377.jpg

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All the component links below (except the hot air gun) go to the same Bright Components (BC) Internet Shopping Site. I have used BC many times and find them reliable and very competitively priced for LED range components.

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1. The 1.8K Resistors (one per pair of LEDs) are general purpose 1.8K (1,800 Ohm) resistors rated at no more than 1/4 watt. The 1,800 Ohm value has been chosen because the power supply is 19 volts DC and not 12 volts.
2. The LEDs are a colour of your choice. For a point mimic panel I suggest 3mm round LEDs.
3. The 3mm round LEDs will need a '3mm Panel Mount Bezel' for easy installation into the panel.
4. You will also need some 'Heat Shrink Sleeving' I suggest some in 1.6mm and 3.2mm diameter. Heat Shrink usually has a 2:1 reduction ratio when shrunk. I use a craft hot air gun to shrink all my sleeving.

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6) And the switches are on/off/on toggle switches of which I have a box of single pole and double too.

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Remember that if you are using these to operate the points, they MUST be momentary action non-locking switches with a sprung to centre off position. These will normally be described as "(on)off(on)" switches and not "on/off/on" as you have written. The (  ) indicate momentary action for that switch function.

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Part 2

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A simple LED circuit that just indicates whether there is power on a DC Analogue track or not can be built from just three components. A bridge recitifier, a resistor and a LED. These components would just be wired across the track rails. The function of the bridge rectifier is to ensure that the LED lights up in the presence of power regardless of the track rail polarity (i.e DC Analogue loco going forward or going in reverse).

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/media/tinymce_upload/8593e18995d625fbf89dee5969487fd5.jpg

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Note however, that the LED will only light when the controller speed is turned up. To my mind this seems somewhat pointless as the observed movement of a loco on the track would show whether power is applied or not.

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Part 3

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In this option, the isolating switch that is connecting the controller to the track would need to have a minimum of two poles. The LED would need its own separate and permanent power supply. This power could be taken from (shared with) the 19 volt DC power supply used to operate the points. In this option, the LED will light when the controller is connected to the track regardless of the controller speed control position. You can still get effective track power isolation by only using a switch contact just on one rail.

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/media/tinymce_upload/beb5472e3d1e680ac9e060ae4df4965d.jpg

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[Chrissaf]

ADDENDUM to last post.

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I am running DC and know that whilst it is probably overkill and I'm not sure whether I will go to DCC in the future so, each track is connected direct to the power via soldered droppers and fed into a bus wire.

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There are IRJs at the connection between the points and beginning of the track for each To isolate them. Whilst the power comes from the same controller, it is not connected to the bus wire but is, instead, a separate cable, for each, coming from the controller which is connected to an on/off switch and then feeds into the track.

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Please note that Insulfrog points are self isolating. They act as electrical switches to route the controller power into the route that they are switched to. If I have understood your written descriptions correctly, then your Insulated Rail Joiners and isolating switches are just replicating what the points are doing themselves naturally anyway, and does rather seem an unnecessary complication. I can however see some form of rationale for it, to make the power distribution 'DCC Ready' for a full DCC BUS system implementation in the future.

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However, rather than implement the isolating switches. You could allow the 'self isolating' nature of the points to perform the power isolation on the sidings. Then for the 'DCC Ready' element, just wire droppers to the siding rails but leave them dangling under the baseboard and unconnected to the BUS wiring. Then if the decision to go DCC is made, it is a fairly simple task to make the final dropper to BUS connections when needed. This was the approach I took when I designed the power distribution to wire up my friends DC Analogue layout.

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[Fozzy84]

Thanks very much for taking the time to reply And explaining as you go. I've got quite a few options to look at now.

 

I have bought the points but could always return them and swap for the PM1 or PM4. 

 

The reason I had planned to use IRJs is due to me getting giddy with the solderMing iron and soldering links between rails on each of the points. 

Whichever route I go down, I'll be sure to upload a picture when l'm done