Wifi control with ESP8266

[drewzero1]

Since the beginning of my garden railway ambitions I've planned to use wifi for remote control of my trains, either by some kind of homebrew ESP8266 or ESP32 solution, or a commercial offering like LocoRemote. Last year as I was building Thornas I ordered some ESP-01 modules and a couple of L298N dual H-bridge motor drivers. The L298N module turned out to be a tight fit inside the boiler and I'm only using one motor, so I may try to find or make a smaller board and save these modules for a larger loco-- but for now it works as a proof-of-concept.

L298N_Thornas.jpg (365.55 KiB) Viewed 1067 times

Note: the small geared motor on the heatsink is just there for testing.

For the software, I'm using this project as a starting point: https://github.com/KushagraK7/ESP-Motor ... on-Control
I know just enough Arduino programming that I think I can modify it to make a more suitable locomotive control. Ideally in the future I'd like to build a standalone controller that uses a dial and switches instead of a touch screen, but that's a project for another day. (Month? Year?)

Here's the wiring diagram I came up with after some trial-and-error (and a mix-up that led to it almost working, but not quite as expected!):

ESP-01_L298N_connections_v2.jpg (32.81 KiB) Viewed 1020 times

Edited to add connection between VIN 3.3v and CH_PD on the ESP-01; CH_PD must be pulled high to operate.

This isn't necessarily a how-to, more just trying to remember what I did so I don't forget it all again for next time!
To be continued...

[Trevor Thompson]

I will follow this with interest!

Trevor

[drewzero1]

After a bit of research it looks like I'll be replacing the L298N with the DRV8833, which is reported to be more power-efficient, cooler-running, and (most importantly) smaller. I'll keep working with this one until the replacement arrives at the end of March.

Meanwhile, the interface as written by KushagraK7 on GitHub:

Screenshot_20240221-195211.jpg (76.22 KiB) Viewed 1025 times

It's actually pretty close to what I think I'd like. There's some inertia built in so the motor gradually responds to the slider, but I'm thinking it might be useful to add an emergency stop button that stops immediately instead of ramping down. An overly ambitious part of me wants to replace the direction buttons with a reverser to simulate steam loco controls, at least for steam-outline models, and a brake control. Since I'll be using this on more than one loco it'd be nice to display the name of the current loco somewhere on the page. Light and sound are definitely on my list but will require a microcontroller board with more than two GPIO, such as the ESP-12.

At this point I should probably note that all of my experience driving trains comes from the MRC Tech-II controller that I use for my HO scale, DC track power... so I'm open to feature/design suggestions!

[drewzero1]

After puzzling for a while over why the ESP would boot on the programmer but not on the ribbon cable I made for it, I realized that the CH_PD pin also needed to be pulled high to boot, and modified the ribbon cable accordingly. (See updated diagram in the first post!) With the L298N connected to a 12v wall adapter and the ESP-01 getting 3.3v from the programmer, this is the result:

0505aa3a-c633-454c-b027-173da8425544.gif (5.89 MiB) Viewed 1019 times

Note, the blue flashing light indicates that the ESP is receiving input on the web interface.

So far so good! I should be able to get that to work on batteries.

[drewzero1]

I should be able to get that to work on batteries.

Technically true I wired up a 2S pack of 18650s to run the motor and a USB power bank with the ESP programmer to provide the 3.3v for the ESP, and the little monstrosity chugs happily around the track. (Edit: video at 100% throttle.)

9af2aeab-d130-471e-8e67-d19004b8a7d6.gif (4.01 MiB) Viewed 957 times

This confirms that a 2S pack can power the loco, so a bit more permanent wiring and miniaturization is in order before I can put the boiler back together.

[drewzero1]

I felt pretty productive last night and checked off two to-dos:

• Switched the ESP to AP mode, meaning it appears as a wireless access point for devices to connect to independent of my home wifi network (or any other). This wasn't necessary for home use as my entire railway site is well-covered by wifi, but will allow me to run the loco elsewhere.
• Added an indicator of the loco name and a crude image. Originally this was a multicolor 28x20px gif (around 650 bytes) but I couldn't figure out how to use #include on that file type, so I hastily converted it to SVG to embed within the text of the control page (HTML). The result added around 1.5KB which still leaves around 600KB free in the flash, but I'd like to try redrawing it in SVG directly and at least make it look better if the jagged pixels aren't helping save any space.

Screenshot_20240223-225946__01.jpg (93.37 KiB) Viewed 899 times

I also attempted to set up a captive portal that would simply redirect to the control page, so the user doesn't have to enter an IP address once they're connected to the AP, but need to learn more about the ESP8266 DNS libraries to get that working. For now I settled for a static IP to avoid the need for a network scan or serial monitor to find out the IP every time it starts.

[Southern188]

Good luck with your project.

I started using Arduinos in my garden rail locos in 2013 and and moved to ESP8266s in 2018. I use the Wemos D1 mini rather than the basic ESPs like the ESP01 that you are using. They have more I/O ports, an analogue input which I use for battery voltage and are easier to program (simple cable to PC).

Everything still works well in 2024.

You can see my system on this forum at:

https://gardenrails.org/viewtopic.php?t=11702

and on another forum on how I modified an LGB 24140 KJF loco:

https://www.gscalecentral.net/threads/b ... co.314042/

A useful read is the loco-remote website that also uses the the D1 mini.

https://locoremote.co.uk/


Michael

[-steves-]

Good luck with your project.

I started using Arduinos in my garden rail locos in 2013 and and moved to ESP8266s in 2018. I use the Wemos D1 mini rather than the basic ESPs like the ESP01 that you are using. They have more I/O ports, an analogue input which I use for battery voltage and are easier to program (simple cable to PC).

Everything still works well in 2024.

You can see my system on this forum at:

https://gardenrails.org/viewtopic.php?t=11702

and on another forum on how I modified an LGB 24140 KJF loco:

https://www.gscalecentral.net/threads/b ... co.314042/

A useful read is the loco-remote website that also uses the the D1 mini.

https://locoremote.co.uk/


Michael

I missed the topic you first did this on and have just had a read through it. Along with those at the time and now, I am super impressed with what you guys have achieved, but alas, way out of my skill set.

[drewzero1]

Good luck with your project.

I started using Arduinos in my garden rail locos in 2013 and and moved to ESP8266s in 2018. I use the Wemos D1 mini rather than the basic ESPs like the ESP01 that you are using. They have more I/O ports, an analogue input which I use for battery voltage and are easier to program (simple cable to PC).

Everything still works well in 2024.

You can see my system on this forum at:

https://gardenrails.org/viewtopic.php?t=11702

and on another forum on how I modified an LGB 24140 KJF loco:

https://www.gscalecentral.net/threads/b ... co.314042/

A useful read is the loco-remote website that also uses the the D1 mini.

https://locoremote.co.uk/


Michael

Thanks for the links! I do plan to upgrade to the D1 at some point for more I/O, but had a spare ESP-01 around for now. (Battery voltage monitoring would be very useful!)

This project has been very much inspired by LocoRemote, having discovered them early in my garden railway journey because of their very compact 3D printable track. My earliest rolling stock all fits around that track, until I joined here and started building bigger kits from the 3D printing section.

I really like your handheld controller. I'm hoping I can figure out something like that eventually!

[drewzero1]

Played around with some SVGs yesterday and managed to get Thornas down to about 900 bytes and Moke (the little diesel) under 800. Looks a little less lumpy too.

Screenshot_20240226-085646.jpg (74.39 KiB) Viewed 778 times

I've also been experimenting with using the button color to indicate selected direction. As I'm modifying this existing code I'm getting a better idea of what it does, and getting more ideas of how to make it work.

[-steves-]

Played around with some SVGs yesterday and managed to get Thornas down to about 900 bytes and Moke (the little diesel) under 800. Looks a little less lumpy too.


I've also been experimenting with using the button color to indicate selected direction. As I'm modifying this existing code I'm getting a better idea of what it does, and getting more ideas of how to make it work.

Looks really good, getter better and better with each revision. The SVG's are soooo much better

[HugoFitz]

I'm definetly following this as I'd really like to use ESP to control my diesel loco I'm planning.

Seen this and thought people might find this interesting as a sound option.



His github is here www.github.com/TheDIYGuy999

[ge_rik]

Wow, that does look interesting. I've not used ESP32 but assume I can transfer my knowledge of Arduino.

Rik

[HugoFitz]

Rik, I’ll start a new thread when I start playing around with it.

[ge_rik]

Rik, I’ll start a new thread when I start playing around with it.

Rik

[drewzero1]

Thanks HugoFitz! I hadn't seen that one before, definitely something to look into for both controller input and sound.

[drewzero1]

The 7333-A regulators and DRV8833 boards came a few days ago (earlier than expected!) and I've just finished working them up. Now most of the electronics fit in the boiler, with some overhang into the cab. There's a lot of extra wiring that needs to be cleaned up, and some that I'll need to add... It ain't pretty, but it works!

Screenshot_20240303-202043.jpg (182.64 KiB) Viewed 387 times

Something's not quite right with the power supply to the ESP... it may need some kind of smoothing capacitor to keep the power steady, but most of the time it seems fine.

d7040993-df23-4911-94e5-8fad04bf0d69.gif (8.79 MiB) Viewed 387 times

I set up the indoor test track and shunted some wagons. My first RC loco, very exciting!

[ge_rik]

Rik

[drewzero1]

Did some more tweaking, mostly UI modifications to make touch control work better. After playing around with it a little, this is the best I've got for now-- though upon further reflection I think I should probably rearrange the controls to the edges where the thumbs naturally fall.

Screenshot_20240305-210910__01.jpg (82.82 KiB) Viewed 227 times

The locomotive image ends up below the fold on my phone in landscape mode, but fits perfectly on my iPad screen.

A physical controller would of course be better in every way, but that may have to be a project for next winter!

[drewzero1]

If anybody's got a spare ESP8266 and wants to play around with it, here's the Arduino project so far. It is based on the original project "ESP Motor Speed and Direction Control" from KushagraK7 on Instructables. https://www.instructables.com/member/Ku ... ructables/
https://github.com/KushagraK7/ESP-Motor ... on-Control

MIT License

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