21st-Century Layout Control

[C855B]

I debated posting this to my layout thread, but it seemed more useful as a general DCC/electronics discussion topic.

I've been messing around with "soft" panels on inexpensive Android tablets for local control of turnouts and whatnot instead of hardwired panels with switches and lit indicators. JMRI's web panel feature has so far worked great with tablets, which I first tried with an iPad2 a couple of years ago. iPads unfortunately were out-of-the-question expensive, even older models on eBay, plus the browser on the original iPad and one or two generations after isn't compatible with the JMRI web service (Javascript issues, I think), and not upgradable.

So the first real test was a cheap refurb 10" tablet controlling the junction at O'Fallons. This proof-of-concept functioned perfectly out of the gate, just needing aesthetic touch-ups. What I concluded in operation and general layout planning was 10" seemed a little large for controlling only nine turnouts, and eventual mounting on the fascia at a convenient angle would poke too far into the aisle.



This is O'Fallons on a 7" tablet. A really cheap 7" tablet. [Menards (a regional DIY chain) was blowing-out these tablets for $35 each* (after multiple rebates).] After buying one and proving it would not only work, but work with "kiosk" software (apps which lock the tablet into a single browser screen), I visited the two local Menards and cleared their stock:

* - Which begged the question, why were these tablets so cheap? It only took a day with the first one to discover that the included keyboards were total crap. Not only are they nearly impossible to use, but almost all have a defect such as random keystrokes you didn't touch. Didn't want the keyboards anyway, so their loss was my gain.



These are maybe enough to do the entire layout except the big yards, which will need 10" tablets at each end.

The concept in general works because all turnouts on the layout are or will be powered and are on DCC buses, controlled by JMRI. The other half of the equation is comm between the tablets and the server, all via WiFi.

I had been cautioned here (thanks, Dave @railnerd ) and also from reading on the JMRI groups.io forum that soho- and consumer-grade WiFi routers don't have the connection capacity for more than a handful of devices. A couple of hours of searching for industrial-strength WiFi access points found this:



The WAC540 is in an unassuming package, but the specs indicate up to 600 simultaneous connections in the three common WiFi frequency bands, 4x4 with beam shaping and MIMO modes. Not going to run out of channels there. I had looked at prosumer routers such as the Netgear "Nighthawk" routers mentioned on the JMRI forum, but those were geared for gamers, prioritizing speed and low latency over multiple users. The commercial router was not only less expensive ($130 from eBay, normally ~$200), but better suited for multiple low-traffic devices as would be found in a hotel or meeting room setting.

Something I'm curious about is if the "600" presumes an even distribution across the three WiFi frequencies, or if I'm going to load it up with a bunch of devices in the 2.4GHz band and nowhere else, unbalancing things and pushing the limits. The older tablets, old smartphones as throttles and the new TCS WiFi throttles know nothing other than 2.4GHz.

New router goes live tomorrow. Certainly not going to be stress testing at this point; I figure sometime next summer for the first op sessions with six to eight live panels and four to six operators all on wireless throttles. Should be fun.

[peteski]

The 2.4GHz WiFi has multiple channels (16?), with each channel capable of supporting multiple connections.  I assume that multiple channels can operate simultaneously.

Friend of mine was planning of creating a similar setup. He mentioned that the JMRI remote panels are network and performance hogs because the panels are bitmaps and ever refresh redraws the entire panel.

[C855B]

The 2.4GHz WiFi has multiple channels (16?), with each channel capable of supporting multiple connections.  I assume that multiple channels can operate simultaneously.

Not quite how it works. Physical channels and device connections are two different things. Many consumer routers can only manage 4-6 connections. Think about the Digitrax LNWI and its four-connection limitation. While I don't know this as a hard fact, I suspect it is due to the internal router's low-end chip/firmware.

Friend of mine was planning of creating a similar setup. He mentioned that the JMRI remote panels are network and performance hogs because the panels are bitmaps and ever refresh redraws the entire panel.

True. The redraw load can be mitigated somewhat through CSS, but if you think of it as a low-res, very-low-rate video stream to each panel, the bandwidth is not all that bad.

[railnerd]

Robert,

You'll want to take care of the batteries in those cheap tablets— we actually put in a dedicated power bus for our iPads while the layout is "off" to prevent float charging them the rest of the week.

-Dave

[C855B]

Thanks. Good point. The plan was to hardwire a 5V bus anyway to each tablet, with manual power-down on every tablet after a session. In the meanwhile I should probably just Velcro the panels to the benchwork face for the time being until the fascia is done, with a local 5V supply during operation, power-down and unplug when done. This'll emulate the long-term plan.

[railnerd]

Thanks. Good point. The plan was to hardwire a 5V bus anyway to each tablet, with manual power-down on every tablet after a session. In the meanwhile I should probably just Velcro the panels to the benchwork face for the time being until the fascia is done, with a local 5V supply during operation, power-down and unplug when done. This'll emulate the long-term plan.

Find a good switching power supply— we were using cheap USB "cigarette lighter" adapters from amazon attached to a dedicated 12V bus**.  Turns out the cheap adapters are just a linear circuit with no brand 7805 crammed inside with some cheap caps— we ended up spending probably more than each of your tablet cost on new adapters that weren't just converting the excess voltage to heat.

**You can't really run a 5V bus very far without the voltage drop basically killing its ability to act as a charge source.

-Dave

[eric220]

I endorse this idea.

https://www.therailwire.net/forum/index.php?topic=30991.msg404109#msg404109

I’m many years from needing this information again, but the tablets are plan A right now.

[Philip H]

FWIW - We use those exact Netgear Routers in our HQ building for work access. Started out every other floor . . and are now being installed every floor due to use case expansion.  They seem to work well so far if the IT staff are to be believed.

[conrad]

Wow, I'm way behind the power curve on "tablet" panels.

I use my tablet for Engine Driver and have used my main, JMRI, computer for a control panel but now just use Engine Driver's turnout listing.

Clue me in on JMRI control panels with tablets.  I love to buy a cheap tablet for a control panel.

Conrad

[Missaberoad]

Very nice...

Should be a slick setup when it's all in place...

Seems a bit too modern for the early 1970s tho, need some of the latest panels from Union Switch & Signal... 😉

[C855B]

... Clue me in on JMRI control panels with tablets.  I love to buy a cheap tablet for a control panel.

First, apologies for not replying sooner. I tried two days ago, but rather, I clicked on "Preview" and thought it had been posted. 

If you've created a control panel that works on the JMRI computer in PanelPro, you already have one that will work on a tablet. It's a matter of turning on JMRI's web server built into PanelPro. Under PanelPro preferences look for "Start Up". If the web server isn't already on the list (should be there by default), then "Add" it. Using the tablet's web browser, enter the same IP address as the WiThrottle/Engine Driver, except use port 12080, like so: http://<your IP>:12080. You'll be amazed by how easy it is to get it going. I know I was.

... Seems a bit too modern for the early 1970s tho, need some of the latest panels from Union Switch & Signal... 😉

Nyuk nyuk. Priority at the moment is doing traditional-looking MRR schematic panels so there isn't a 4-hour training session for visiting operators in how to run a tower. That said, it's sort of cool that JMRI accommodates multiple panels addressing the same controls. I could have a MRR-type panel, a US&S toggle board or even an armstrong simulation for the masochists, all available, pick one. I had the opportunity to "guest run" a couple of 1:1 armstrong towers - obviously long ago - and it's a real mental challenge to associate lever actions with what's happening on the diagram and outside the windows. With a train bearing down on us, I had one guy tell me "OK, throw 42!" I reach for 42, and it's connected to... nothing. It just flops around, while he pulls the actual lever needed to clear the signal. Very funny.   

[wm3798]

Micro chips.  Placed just behind the ear.  All you have to do is think about which train to run, and voila!

I'm working on a rig that employs vacuum tubes and toggle switches.  And a generator operated by a Studebaker V6.

Lee

[conrad]

First, apologies for not replying sooner. I tried two days ago, but rather, I clicked on "Preview" and thought it had been posted. 

If you've created a control panel that works on the JMRI computer in PanelPro, you already have one that will work on a tablet. It's a matter of turning on JMRI's web server built into PanelPro. Under PanelPro preferences look for "Start Up". If the web server isn't already on the list (should be there by default), then "Add" it. Using the tablet's web browser, enter the same IP address as the WiThrottle/Engine Driver, except use port 12080, like so: http://<your IP>:12080. You'll be amazed by how easy it is to get it going. I know I was.

Thanks, I did have the web server on at start up but had to go to "web server" and check box for "start automatically with application".  Works well but I have to work on look of panel.

Bty, at my age (75) the faster the response the better:D  Every morning I check the NYTimes obits.  Gotta make sure I'm not listed!

Thanks again,

Conrad

[Point353]

Micro chips.  Placed just behind the ear.  All you have to do is think about which train to run, and voila!

Don't forget the antennae.

[Carolina Northern]

@C855B Will your RPi have enough horsepower to run the web server for multiple panels and the Wii throttle server at once?