Digitrax announces LNWI - Wireless LocoNet Interface

[reinhardtjh]

I'll put this in "Product Discussions" but it probably should be moved to "DCC / Electronics" at some point.

Digitrax has announced a wireless LocoNet interface:  The LNWI
   Instruction sheet  -->  http://www.digitrax.com/media/apps/products/wireless/lnwi/documents/LNWI_rev.0.pdf
   Tech Notes -->  http://www.digitrax.com/tsd/product/LNWI/

Highlights:

• Works with Engine Driver for Android and WiThrottle for iOS
• Supports up to 4 wireless devices (throttles) per LNWI - More on this later
• Up to 8 LNWI supported per LocoNet
• Optional WPA security

The thing is supposed to nearly plug and play, at least for one unit.  When you add more, naturally things get a little more complicated.

Issues I can see at first look:

1) Each unit only handles four (4) wireless devices.  At a MSRP of $79.95 the number of devices seems a little low.  I don't know the internals but I'm betting there a Raspberry PI Zero like computer running some form of Linux with the throttle server portions of JMRI.  Unless the WiFi hardware used has some severe limitations or there is an extremely small memory, 4 connections is low.  Possibly some hacking could be done.

2) The WPA security I'm not sure about.  Really can't see much use for this the way they have it set up.  From what I get out of the instruction sheet and the Knowledge Base articles, the password is fixed to a known value! If there is a way of changing it, I haven't seen it.  Is security even necessary?  The LNWI is not connected to any internal, home or internet network (unless it's a hidden feature not yet revealed) so why worry about someone getting into your Loconet?  The manuals talk about WPA security but why not WPA2?  It's not much better, but it's something. Plain WPA is old and has known cracking methods.  Hopefully the software/firmware on the LNWI is user updateable and Digitrax will issue them at some point.

3) The WiFi SSID's presented are of a fixed format - "Dtx1-LnServr(x)-7" where (x) varies from 0 to 7 as you add devices.  What happens at a show when several different layouts have LNWI's of the same SSID?  The SSId seems to be an awkward format as well.  Whyt he "-7" on the end of all SSID's?  Maybe the instruciton sheet is wrong.  There are other errors as well.  I see an error at the end of the instruction sheet for the link to the LNWI Advanced configuration web address.

4)  "Digitrax does not produce or support Mobil Devices or Throttle apps" - How quickly will Digitrax update the LNWI software to track changed in the WiThrottle connection protocol?  I know the WiThrottle server on JMRI has evolved.  Will the LNWI also need periodic changes to keep up?


Edit: Clarify and add issues

[C855B]

...
1) Each unit only handles four (4) wireless devices.  At a MSRP of $79.95 the number of devices seems a little low.  I don't know the internals but I'm betting there a Raspberry PI Zero like computer running some form of Linux with the throttle server portions of JMRI.  Unless the WiFi hardware used has some severe limitations or there is an extremely small memory, 4 connections is low.  Possibly some hacking could be done. ...

I strongly suspect you are right and it's a Pi Zero with a JMRI subset, but - more importantly - also running a router daemon. My hunch is the router is the limiting factor on the underpowered Zero. As far as hacking, adding or modifying is likely to stress processing limits.

We (our club's DCC committee) had a lengthy text chat this morning on this news. We were also wringing our hands about the limitations. Our conclusion was to get one anyway, that we already have DT40x throttles coming out of our ears, and it will be a while before our particular group has enough combined savvy to be running >4 phone throttles at shows. The question was raised of how the throttle limit is (or isn't) enforced, and whether it's mostly just a statement of expected capacity.

We didn't raise the issue of multiple clubs at shows. I think that's what the WPA security is addressing, that you connect only to your "authorized" hub, and "so what?" if there are collisions at what might be a common base address at the hardware layer. I personally think there would be greater issues with another club using NCE wireless, which tends to be a 500-pound gorilla in the 2.4GHz unlicensed spectrum.

[C855B]

One of the guys just texted, "What if you're setup at the show next to the snack bar and they use a microwave?"

[railnerd]

One of the guys just texted, "What if you're setup at the show next to the snack bar and they use a microwave?"

Never had a problem at two different NTS shows and a few more GATS fathering— our Free-moN setup uses a small linux machine running WiThrottle for years.

[reinhardtjh]

We didn't raise the issue of multiple clubs at shows. I think that's what the WPA security is addressing, that you connect only to your "authorized" hub, and "so what?" if there are collisions at what might be a common base address at the hardware layer. I personally think there would be greater issues with another club using NCE wireless, which tends to be a 500-pound gorilla in the 2.4GHz unlicensed spectrum.

That does make a bit of sense.  Except that, as far as I can tell from the info give, the WPA pass phrase is hard coded into the LNWI and not changeable by the user.  I sure hope not, but that what the documentation seems to say.

[RBrodzinsky]

This looks like a mildly expensive solution looking for a problem. Any DCC layout (NEC, Digitrax, Lenz, etc) that can interface with JMRI already has an easy way to have nearly unlimited iOS or Android throttles: just connect a regular WiFi router into a computer running JMRI. The computer can be as simple as an R-Pi that boots up JMRI with WiThrottle Server activated.  We run the SV FreeMoN layout this way, and rarely use anything other than phone/tablet throttles.  Upwards of a dozen throttles at a time, with never an issue. Our router does not connect to any external network, so is self contained.

[C855B]

I just confirmed the WiFi is 2.4GHz only, FCC registration #2AC7Z-ESPWROOM02. No escaping that microwave.

... Any DCC layout (NEC, Digitrax, Lenz, etc) that can interface with JMRI already has an easy way to have nearly unlimited iOS or Android throttles. ...

The problem in our show setting is somebody has to set the SOB up. That's frequently me, and I can't be at every show. The plug'n'play of the LNWI is attractive for the guys who already have enough trouble just getting the basic DCC system to function. We can generate all the instruction sheets in the world - even laminate them! - and, still, I get the phone calls when trains won't run.

[jdcolombo]

We don't need this, although I can see a use for it for those that don't want to set up JMRI.

What we DO need is an actual dedicated WiFi throttle, with a throttle knob and hard buttons that doesn't cost $300.  A simplified ESU Mobile Control II.  Cell phones are great, but when you are operating trains, the tactile feedback from a real throttle is critical, IMHO.  I don't want to be looking down at a touch screen when I'm doing operations; I need to be looking at the train.  The Digitrax UT4 is a perfect handheld throttle for this - nice big knob, some real buttons for function keys, and a toggle switch for direction.  You can run a train, even a sound-equipped one, without ever looking down at the throttle.  Turn the UT4 into a WiFi-equipped throttle at a $100 price point, and I'm in for a half-dozen.

John C.

[nstars]

We don't need this, although I can see a use for it for those that don't want to set up JMRI.

What we DO need is an actual dedicated WiFi throttle, with a throttle knob and hard buttons that doesn't cost $300.  A simplified ESU Mobile Control II.  Cell phones are great, but when you are operating trains, the tactile feedback from a real throttle is critical, IMHO.  I don't want to be looking down at a touch screen when I'm doing operations; I need to be looking at the train.  The Digitrax UT4 is a perfect handheld throttle for this - nice big knob, some real buttons for function keys, and a toggle switch for direction.  You can run a train, even a sound-equipped one, without ever looking down at the throttle.  Turn the UT4 into a WiFi-equipped throttle at a $100 price point, and I'm in for a half-dozen.

I fully agree, the UT4 is also our preferred throttle. The only thing I'm missing is a small indication of the status of the function buttons (especially with sound loco's).

Marc

[John]

This looks like a mildly expensive solution looking for a problem.

agree .. and I would use a R Pi as well .. but when you figure the Pi, locobuffer, etc .. the price point is pretty competitive, especially if you have a home layout and 3 or 4 guys come over to play trains ..

[GaryHinshaw]

Turn the UT4 into a WiFi-equipped throttle at a $100 price point, and I'm in for a half-dozen.

John C.

I suspect that someone will produce such a throttle within a year or two.  Bonus points if it has a small touch screen for displaying jmri web pages.

[sirenwerks]

I think I like the sound of the product but you guys are talking way over my head. What about this... http://bluerailtrains.com/

[pdx1955]

For what it is, this seems like a good product. I think if you already had your layout connected to a computer with JMRI or plan to have , then this is really overkill and you should just add a router to support the WiFi throttles as you already have invested in the hardware. For myself, I have my fixed Zephyr station plus a couple of wired throttles so addition of this product to support a complete WiFi solution could be a good way to go. The layout is not big enough to support anymore than 3-4 operators and I don't have radio throttles so this would  be less expensive  than going that way. Almost everyone has a phone that would work with a throttle app but not everybody has a throttle so it might make it easier for guest operators if they didn't want to use a wired solution. 

[Lemosteam]

For those who have not yet invested in JMRI or a comport er interface, this is a very welcome addition at what I think is a very reasonable price. I will be getting one for sure.

[reinhardtjh]

Digitrax has been adding and updating the Knowledge Base articles on the new LNWI interface and they address some of the questions I had.

2) The WPA security I'm not sure about.  Really can't see much use for this the way they have it set up.  From what I get out of the instruction sheet and the Knowledge Base articles, the password is fixed to a known value! If there is a way of changing it, I haven't seen it.  Is security even necessary?  The LNWI is not connected to any internal, home or internet network (unless it's a hidden feature not yet revealed) so why worry about someone getting into your Loconet?  The manuals talk about WPA security but why not WPA2?  It's not much better, but it's something. Plain WPA is old and has known cracking methods.  Hopefully the software/firmware on the LNWI is user updateable and Digitrax will issue them at some point.

So the WPA password can be changed using the DigiGroupSetup Utility (same program you use to change the group name on a UR92).

See KB1056: LNWI Security Considerations: Enabling and Customizing WPA2 Security

3) The WiFi SSID's presented are of a fixed format - "Dtx1-LnServr(x)-7" where (x) varies from 0 to 7 as you add devices.  What happens at a show when several different layouts have LNWI's of the same SSID?  The SSId seems to be an awkward format as well.  Whyt he "-7" on the end of all SSID's?  Maybe the instruciton sheet is wrong.  There are other errors as well.  I see an error at the end of the instruction sheet for the link to the LNWI Advanced configuration web address.

The SSID is also changeable using the DigiGroupSetup Utility (portions are also settable using a DT40x/500).  The KB note KB1053: LNWI Advanced Options has the details.  THe SSID consists of a fixed "Dtx_", WiFi channel number (changeable 1-11), Net name (changeable), LNWI serial number (fixed) and a net number (changeable 1-7).

The fact that the DigiGroupSetup Utility is used for some of the options makes me wonder if the same WiFi radio module that the UR92 and radio throttles use are also used by the LNWI.  With the changeable WiFi channels it will be interesting if you have to avoid the channel your Duplex radio UR92's are using (if you have Duplex).