Insulated Rail Relay Based Sensor

I think that's a good idea. I don't recall seeing much (or anything) like this for 3 rail. I do think it would fill a need and would be worth a try. Of course, if you posted the gerber files and parts list I would certainly try this one myself at the inexpensive PCB maker you found (forgot the name).    It just might be too good of an idea to do that with though.

We are discussing the IR detectors in another thread (ITADs and Making Your Own) and the IR devices are, so far, having some problems, but more things to try are in the works. Your input is welcome, BTW, if you haven't been there already. 

John

If your looking for feedback I think this is a great idea and would buy these if you bring them to market.

Bill

Nice design, I would be interested in a few.

I would be interested.

Dear John

Nice simple design. What would the manufacture (you) suggest retail price for one of these?

John

Looks like another winner. I have been using the SPDT version based on input from you and Stan 2004  in the past with no problems. I have also been looking at A DPDT version using the same relay with terminal boards for ease of connection as shown above. I'm sure this will go over big wheather it be in kit form or completely assembled for those who are adverse to assembly and soldering.

Gerry

I have a couple of prototype PCB's coming, and I am trying to line up cheap components.  Note that I used all thru-hole stuff as that's typically easier to get cheaply and also makes it easy to build.  Maybe there'll be some low cost kits in the future.   It's a basic circuit, and one I've been using on our club layout hand building them.  I figured I'd like to have about 15 of these myself to replace the hodgepodge of stuff we use.  I did find some nice terminal blocks for a very good price and ordered a bunch of them.  I know I can use them somewhere if not here.

I'd like it to be cheap, in the $10 range, depending on the component costs.

Hey John,

You know more about the relay you are using than I do so I will just ask......

Do you think there is a need for a northbound diode across the coil?

Lou N

That thought crossed my mind, but I've been using this relay in a similar lashup for a long time with no ill effects.  It has a 15ma coil, so any kickback seems to get lost in the cap.  I've had them running several years running signals, still running.

In the off chance that it should prove to be an issue, I left provisions for an SMT diode at D2 on the left.

So will this trigger an MTH per signal bridge?

You get relay contact closures when something is on the insulated rail with bounce protection.  If you can trigger it with something like the MTH ITAD, you can trigger it with this board.

prrhorseshoecurve posted:

So will this trigger an MTH per signal bridge?

If it does count me in for a bunch!

Hi John - Great looking easy circuit - I'd be in for a couple.

I'd be interested in some too!

gunrunnerjohn posted:

That thought crossed my mind, but I've been using this relay in a similar lashup for a long time with no ill effects.  It has a 15ma coil, so any kickback seems to get lost in the cap.  I've had them running several years running signals, still running.

Thanks John. Perfect timing. I had a call today from a friend asking about IR devices and I said there were better ways. Will look forward to your new product introduction.

Lou N 

I would be a buyer too !!!!   come on John what are you waiting for !!! lol Let's go, they should be packaged and ready to go !!

Alex

Well, I have to get some parts in and actually assemble a few for final tests.  Since it's a circuit that I've been using, I really just want to see the boards and make sure the components like the terminal strips and the like actually fit with the current layout.  I've been burned too many times buying a bunch of boards, only to find out I made some spacing error!

Lou, see previous post, I added a SMT diode on the end in case for any reason I deem the diode should be there.  I didn't want to make the board any larger for the full sized diode.

I would definitely take some too. Kinda what I was getting at at my earlier post referring to the gerber files and trying it myself. Assembled, kits, boards with parts list, any way is fine with me. I do like the idea of the through hole components for the kits though, I think many other will too. But I do need to try that SMT stuff one of these days.

Also, I still haven't forgotten trying the Watchdog devices. I'm still missing some parts for the layout changes I want to make. If I don't get them pretty soon I will go ahead and try them and rework things later on.

John:

Am I reading the diagram right as you show the relay being powered by the “center rail”?  If so, that means it can be powered from an AC transformer thereby eliminating the need for a separate DC power supply, which is another selling point. 

But why connect it to the center rail?  Why not an accessory power terminal instead because in conventional layouts the power to the center rail is quite variable. 

Bill

There's no reason at all why the unit couldn't run from any aux power source, AC or DC for that matter.  I confess that I'm always thinking command operation and I always have 18 volts handy on the center rail.  It just needs a voltage that has a common with the outside rail.

gunrunnerjohn posted:

There's no reason at all why the unit couldn't run from any aux power source, AC or DC for that matter.  I confess that I'm always thinking command operation and I always have 18 volts handy on the center rail.  It just needs a voltage that has a common with the outside rail.

John:

Thanks for verifying that as it will greatly reduce the complexity.  Be prepared to sell out at York!

Bill

Unless I sell out before York!

rtr12 posted:

But I do need to try that SMT stuff one of these days.

SMT boards can be a lot smaller, but it is more trouble to assemble them.  Obviously, for stuff that I sent out to an assembly house I use SMT, things like the Super-Chuffer would be impossibly large with thru-hole parts.

Add me to the list of customers for these new boards.

The talent here never ceases to amaze me! Great job GRJ ! 

GRJ, You beat me too the punch hahaha I have a similar circuit set up on a prototype bread board bench testing it to make sure it works before field testing. We too have a "hodgepodge" of detector circuitry for signaling at the GSME club. Hoping this will clean everything up! 

GRJ, now having a totally blank benchwork, I'm sure I could find places for half dozen of these.  Keep me in mind if you decide to produce.

John, I'd be interested in getting a number of these to replace the relays I'm using now for signals. Nice work!

Seems like a simple, straight forward approach.  I think for this particular product a fully assembled board would be the most marketable. 

JGL

Nice job John!  Is there any provision or perhaps add-on module that would add time delay to this. Thanks.

Bruce

I was just thinking about something like this.

i could use at least a couple or three

i would be interested in a kit, but all built would be fine as well

BruceT47 posted:

Nice job John!  Is there any provision or perhaps add-on module that would add time delay to this. Thanks.

Bruce

I'm surprised it took so long for someone to suggest this.   I confess that thought crossed my mind.  The attraction of this design is that it's simple in concept and execution.  If I started adding features, I don't know what would make the most sense.

Nice John, if you get around to selling them are they going to be as easy as these?

Hi John,

I need a gizmo like your circuit to trigger Rail King crossing gates, Rail King crossing flasher signals, a K-Line shanty signal man, and the signal man inside a Rail King boxcar. If your circuit is rugged enough to handle these loads individually, I will be a customer.

mike g. posted:

Nice John, if you get around to selling them are they going to be as easy as these?

Even easier, all screw terminals for the connections.

Bobby Ogage posted:

I need a gizmo like your circuit to trigger Rail King crossing gates, Rail King crossing flasher signals, a K-Line shanty signal man, and the signal man inside a Rail King boxcar. If your circuit is rugged enough to handle these loads individually, I will be a customer.

The relay contacts on these are rated at 2 amps.  It was a tradeoff on price/size/power handling.  Higher capacity relays are larger and, have more coil current, and are typically more expensive.  I suspect most of the stuff you mention shouldn't need 2 amps, but I'm not sure of everything.

Good morning John

I have never done isolated rail thing, how long does the isolated rail have to be and how far from the grade crossing protection can it be ? Also will this work with Z Stuff ?

thank you 

Clem k

I have been using these similar boards. Unfortunately, the company no longer exists. With the jumpers they have endless possibilities: timers, flashers, one on one off combos, etc. I have four and one for lighting also. They still need an isolated rail input, so that is why I was looking into the ITAD possibilities for track I didn't want to rip up. They make hooking up signals and gates much easier, as would John's. With diodes on the inputs, I can hook more than one on the same relays, like a signal bridge and crossing gates for two track operation. Great idea, John. Your little gray cells are always at work.

gunrunnerjohn posted:

rtr12 posted:

But I do need to try that SMT stuff one of these days.

SMT boards can be a lot smaller, but it is more trouble to assemble them.  Obviously, for stuff that I sent out to an assembly house I use SMT, things like the Super-Chuffer would be impossibly large with thru-hole parts.

Probably just a try would be sufficient for me, don't think I would want a steady diet of SMT to assemble. Sending those out sounds like a good plan to me. I am amazed at how small things can be made with SMT.

I think the time delay suggestion above might open the door for another module, but I think you are right to keep these simple and as they are. I think there would be many more users that way. You could add the time delay, larger relays, flashers or whatever in separate modules later if the demand is there. A modular system so to speak.