Hello everyone. I'm new here and I've been looking for some information on Railcom+ and decided to join and see what I can find out. I'm interested in knowing if there are any plans out there where you can make your own DIY Railcom Transmitter. I'm interested in seeing if I can DYI my own rather than purchasing one. I've been thinking about using the smallest ESP32 but then I need to power it off the DCC rails and be able to not disrupt the DCC signal so I would need some kind of optocoupler or something like that for both power and getting the signal. This "package" of course needs to be small enough to fit in my rolling stock. I've looked into the ESU transmitter and I wanted to see if I can build one a little cheaper if that's even possible. But I consider it a challenge if I can do it or even find the information which is been hard to get. I see command stations built on the ESP32 but that's pretty much about it. With like the standard ESU transmitter I don't know if it's some kind of special processor or something like that. I can't find out that information or I just don't know what to look for. Does anyone know if that is even possible for a small footprint as rolling stock and doing it DIY? Any info you can supply would be greatly appreciated. I also looked into the Digitrax TL1 but it seems Railcom+ is much more functional when it comes to providing information on the loco/rolling stock. I'm not looking for any kind of multiple functions, just ID of the rolling stock. Thanks and happy railroading! Glen
Welcome aboard! What scale are you targeting? Z, N, HO, ...? That will make a difference in how much room you likely have in a loco or a railcar, and what options you have for implementation. First, you will need to build (most of) an ordinary DCC decoder, because you have to recognize the time period within the DCC command when RailCom does it's thing. Your post title indicates RailCom+, while your message mainly references RailCom. Which one do you want? What do you want to be able to do with it?
So a fairly standard DCC decoder setup but with RailCom TX support. This is doable and the ESP32 can be used for this, but you will be hard pressed to fit it inside anything smaller than HO scale. I've designed an N scale decoder (using ESP8684 which is a QFN24 packaged ESP32-C3) supporting sound, WiFi control, DCC and RailCom. However, due to size constraints I ultimately set the design aside. It may return as an HO scale decoder and be a commercial product at some point. You likely saw my ESP32 Command Station project, it's not the only one out there now but it is the source for most other projects in generating the raw DCC signal. There are also a few commercial designs being worked on using ESP32 chips, I can't share too many details on these as they aren't publicly announced yet but what I can say is it's not limited to just command stations and they should be hitting the market in the next couple months.
Yeah. I guess I should have probably mentioned what size I'm looking to design for, it's HO. I'm not sure of the exact differences between Railcom and Railcom+ but since I'm only looking for basic functionally as to tell me what car is where, I would says Railcom. I have not seen any specific sketches that deal with Railcom, most of them are for DCC functionally such a lighting and switch/servo control. I'm just looking to ID the railcar and that's it. I've looked into RFID and other types of identification systems but since I have an ESU controller, I figured Railcom would be the easiest to work with. For me it's just that pesky, how do I power and ESP32 from the rails while still reading the rails without disturbing the DCC signal or missing the Railcom packet. While it's been almost 30 years since I worked/designed any kind of electronics, I'm looking forward to the challenge. Glen
Yes, that's kind of what I figured that fitting it in HO would be fairly easy for the most part. Some railcars more difficult than others but it's doable. I'm just having issue finding a design to power and grab the data from the rails. I figured for me a 2 board design would be for me. One board to have the optocoupler and rectifier to power and of course the other being the ESP32. I figured since I'm only looking for railcar identification, I could get away with a tinyesp and I would not need any kind of functional lights, sounds, etc. But that powering circuit and the Railcom code eludes me. I think I did find a circuit to power, I just have to see how much I can stuff onto a small prototype board to see if it's doable. Where is the one chip design that magically does everything you want. Glen
If/When I find that I'll let you know You could take inspiration from designs such as https://github.com/nsm81/DCCLink_PCB. You will need to adjust the optocoupler output pin (pin 6) to pull-up to 3v3 instead of 5v. I have a design for a DCC/RailCom decoder but it is not fully tested and derives power from an OpenLCB / LCC connection rather than track connection, which can be easily be added via a bridge rectifier circuit. However, this hasn't been released publicly as it was an internal test tool primarily.
I see ESU has a transmitter that can go in rolling stock but looks like it is about $60 (street price). I would think you could use ESU's 59826 LokPilot 5 Micro DCC Decoder ( HERE ) and not use the motor functions. Maybe not??? It is really small and should fit even in some N scale rolling stock. Looks to be smaller than their RailCom Transmitter. At $30 not sure you could build something for much less. Sumner
On the tippy-top shelf, with a price tag that takes everything you have. The task of a product developer: Create a product that enough people need, at a price they are willing to pay, while turning a profit that will keep the the developer in business.
https://github.com/atanisoft/ESP32CommandStation/ There is also a very long thread on here. It's fairly stable now but there are a few rough areas still which are tracked via issues. I don't have nearly as much time to dedicate to this project (or many of my others) lately, mostly due to working on a couple commercial products that should hit the market in a few months. I can't share too many details on the products yet but what I can say is that the company that will be selling these products is quite well known in the model trains world and is overdue on announcing new products. RailCom is involved in at least two of the products.
