Building a physical, tactile knob based throttle controller for JMRI using an ESP32 - Part One

[@iannelson6323]

Fantastic as usual, bring on part 2!

[@WirenwoodModelRailway]

Ha, thank you Ian! Wire arrived today, LCD screen should arrive tomorrow and I'm completely immersed in it so part 2 probably won't be that long away! Regards, Chris

[@aleopardstail]

thought on the screen. have the throttles arranged in one vertical column, stick the screen to the left or the right, something like a 320x240 2.8" TFT (the ESP drives these nicely), or multiple of the 128x32 OLED screens through a I2C multiplexer - you now have space for a display for each throttle even if just two lines - loco ID name or number and the throttle with a direction indicator given you already have a "which throttle am I talking about?" selector I'd then look at having some buttons, using one of the I2C port expanders so its no additional pins, unless you want the interrupt functionality, then you have say 8 function on/off push buttons. could also even automate things like lights to turn on when a train starts moving if not already on, and maybe turn off if the throttle releases the locomotive. only have five chipped locomotives here, I am pondering a second encoder to drive two at once (currently only set up for one). adding the screen, buttons and a keypad however has proven quite simple, and doesn't take many pins. plus if you are not bothered about having it be portable a small console is quite practical with one of these things mine in total is one screen, one encoder, one 4x4 keypad, an array of 8 buttons on an I2C expander and a single bright red button wired direct into "power off". the code needs work, it works but occasionally crashes so something wrong somewhere, I modified the Arduino WiThrottle library to be able to respond to more information, its not hard to do though note also having several WiThrottles works well, you have a better screen set up than me but I was thinking of having another for just points control for example

[@WirenwoodModelRailway]

Thanks Dale - yeah I moved on from thinking about portable. If I do need to take a throttle to the other end of the loft I can always just grab a phone or tablet. I think having this box situated near the other controls - points etc - makes sense. Still don't know where / how I'm going to mount it! I've got a 20x04 LCD working in test now, it's fairly straightforward and just about does the job, next job build a new, tidier, more sturdy version of the box. I didn't think to look for an Arduino WiiThrottle library, coded it all myself! Still, best way to learn I guess. Regards, Chris

[@aleopardstail]

have built something similar here, though only a single knob. I found it very helpful to add a display, using a 128x128 colour TFT, but only because I had one, the little .096" OLED are good for this - can show the train ID and its current speed. have also added a 4x4 keypad and some other buttons. all on breadboard currently, though set up here to have a nice red E-Stop, press "A" then type a number, press "#" and select a locomotive. it is extremely simple to add battery power, there are ESP32 boards that have the battery hardware and a socket for a 18650 battery cell on the board. IIRC you can "lock" a locomotive to the WiThrottle, but you will also be sent the current throttle setting when something else changes it all in development, the screens are very easy to add, even the 1602 LCD ones are good, the little OLED ones are better though, its well worth playing about with as its quite easy to control functions on locomotives, e.g. lights/sound at the same time it really is quite amazing what JMRI and WiThrottle can do

[@WirenwoodModelRailway]

Hi Dale - really interesting! You're right - it is very powerful. The keypad is something I deliberately avoided - something that I think JMRI on the whole is very good at is hiding all those numbers. I assign an address to a loco then forget about it, because it's only referred to by its name from that point onwards. I only have about 22 'usable' locos - I've filtered them into a sub-roster group and WiiThrottle only offers that subgroup up to clients. So I like the idea of not having to remember DCC addresses - the screen will just show the names of the locos as I scroll through, until I find the one I want. For the time being I'm going to try to go with a very basic screen - a 2004 LCD. It might well be enough - by default just show what's assigned to each of the 5 throttles, but those function and assignment wheels will let you scroll through the 5 throttles and see what's assigned to them. Early days - the screen hasn't even arrived yet! Regards, Chris

[@aleopardstail]

@@WirenwoodModelRailway that method of scroll through the assigned names should work nicely, and with the rotary bit very nicely, scroll either way and press to select is perfect for it, just need to keep the assigned names short enough to read. I went with entering numbers as well, I don't have many and the numbering is simple, e.g. my class 47 is "470", my 86's are "860" & "861" - though they do all have names. may actually be worth pinching this idea and adding a "scroll to select" option. those 2004 LCD are good, seriously simple to use as well with the I2C backpacks. and not hard to have custom characters if you wanted a bar display for speed (though to be honest just the speed step & direction is fine) that screen will be plenty once its working, even if you only show information on one loco (last one adjusted) or last 1-4 adjusted) you can fiddle with the I2C backpacks to change the I2C address to run several, bit of a faff though, and given most commercial DCC handsets don't exactly show a ton of information should work well. experimenting is half the fun

[@RustyTracksRR]

I do a similar thing with my N Scale switching layout running DCC-EX and Engine Driver on an Android tablet. Although I only have a switching layout I got tired of holding the tablet and confusing one of my four locos on the sliders...lol I bought some (4) USB volume controls from Amazon and plugged them into a USB hub plugged into my tablet. I assign one control per loco at the start of a session. I use the 'push' of the encoder to stop the locos. Turning the encoder to the right gives me forward and the the left reverse. I did try an upgraded version (with a 'previous', 'play/pause' and 'next' buttons for Bell, Horn and Startup) of these controllers but it didnt recognize the individual units like it does with the basic one. Anyway great video!!!

[@WirenwoodModelRailway]

Great work! I didn't even know you could plug USB devices into a tablet! I think the tablets I use - old, long since discarded ones - can be a little unresponsive from time to time which isn't great when I'm trying to slow a train down! Thank you for the kind words, regards Chris

[@thegaryiward]

I would love to see how you built and coded these. This is something I would like to try building

[@WirenwoodModelRailway]

Hi Gary! I'm currently in the process of building v2, with screen, and I'm filming much more detail on the building of it. Once the code is finished and proven bug free as much as possible I'll release it on my Github - it's there already just in a private repo. Regards, Chris

[@thegaryiward]

Looking forward to it. You seem to be the same as me when it comes to model railway. Lots of tech and building. I like creating and coming up with solutions.

[@yenraccarnivor]

@@WirenwoodModelRailway i cant wait to get this one running, got my dials ordered :D

[@WirenwoodModelRailway]

@@yenraccarnivorHa, it's on its way! The box is finished and working now, the video made, I just need to clean up the code a bit! Regards, Chris

[@DuncSargentsKarstValleyRR]

Sweet!