NMEA via ethernet/wifi

[FlyingCloud1937]

Mollymawk,

What you want does already exist.

VSCOM - Data Communication, Network Device Server

It's app/smartphone/tablet ready plug and play.



I have plugged into my multi-plexer, which are 0183 wired to my Simrad CP, and my Raynav CP. I can up/dn load to either unit. Run my wifi laptop/tablet/smart phone.

Lloyd

[Mollymawk]

Originally Posted by nohal

There's always something to learn A RasPi will probably get you as close to your 100mA goal (don't have one to measure) as possible, but it's not powerful enough to be seriously used as a nav station.

Yes. The main attraction of the Pi is its price, but it's so low powered that as you say it's not much use as a dedicated computer. It would make a lovely "controller" for a project like this though, I guess...
It's something I'll consider, tough I'm still averse to the idea of using a whole computer for something that only needs something much simpler. Apart from anything else it adds complications such as startup time to a device which might as well be instant-on.

Originally Posted by nohal

You could get even simpler (but not cheaper) with something like an Arduino with ethernet shield, it will be reasonably simple to write something mirroring serial input to net exactly the way you like it, if you know some C.

I'd love to use an Arduino for this... but as you hint at, they've always seemed to me a bit expensive for what they are.
That said, I guess it's the obvious way to create what I want.
This board would be a more cost-effective way of doing it than an Arduino with an ethernet shield, I guess.

I'm not familiar with the Arduino, but I've always liked the idea of playing with one.
I'm not good enough with C to make it "easy" (nor with Arduino's "Wiring"/"Processing" environment), nor am I familiar with the protocols I'm looking to handle, but that just makes it more interesting and more worthwhile.

Originally Posted by nohal

If you want something dedicated to this task, you can buy https://www.sparkfun.com/products/9476 which does it the "hardware" way - note that it costs almost the same as the Raspberry and in reality has quite some electronics inside and takes 180mA@5V which will be almost 100mA@12V counting the loss of a voltage regulator...

Now we're talking. I think. But what does this device actually do? How do I access the NMEA data over the ethernet? Presumably it would involve some kind of drivers on the computer side to create a virtual COM port? I'm not familiar enough with either serial interfaces or networking to know what's possible.

Originally Posted by nohal

What I'm using to build the nav computers are the stock passively cooled mini-ITX boards with either picoPSU or custom built power supplies. If you have enough power to run laptops and wi-fi, you imho also have enough to run one of these...
If you want to experience some ARM adventure, mk802 v2 is the device you want to have a look at - has more power than the Pi and costs way less than a Beagle or Pandaboard.

I've thought about using a cheap Android tablet as a navigational computer - you get a reasonably powerful computer with a good low-power screen for relatively little money - but to be honest Android is a bit restrictive for my liking, and other OSes like Ubuntu don't really work on these sorts of devices yet. Still, if I were going to go the Android way a tablet would seem like the way to do it. If I could put up with a 7" screen, that is. Hmm, maybe not after all...

---

Originally Posted by FlyingCloud1937

What you want does already exist.

VSCOM - Data Communication, Network Device Server

It's app/smartphone/tablet ready plug and play.

I have plugged into my multi-plexer, which are 0183 wired to my Simrad CP, and my Raynav CP. I can up/dn load to either unit. Run my wifi laptop/tablet/smart phone.

Now that does look interesting, but so far as I can see it only has drivers for Windows.
So how do you use it from your tablet and smartphone? Presumably by some other method than a virtual COM port? How do navigational apps on the tablet/smartphone access the NMEA data?

---

Originally Posted by sushirama

Hey this stuff is pretty similar to AppleTalk.

What is pretty similar? And hang on, AppleTalk was abandoned about 10 years ago... it's modern equivalent is Bonjour/Zeroconf, but I'm not sure how that set of protocols would help me do any of what I want to do here. Please elucidate.

[FlyingCloud1937]

Originally Posted by Mollymawk

Quote:
Originally Posted by FlyingCloud1937
What you want does already exist.

VSCOM - Data Communication, Network Device Server

It's app/smartphone/tablet ready plug and play.

I have plugged into my multi-plexer, which are 0183 wired to my Simrad CP, and my Raynav CP. I can up/dn load to either unit. Run my wifi laptop/tablet/smart phone.

Now that does look interesting, but so far as I can see it only has drivers for Windows.
So how do you use it from your tablet and smartphone? Presumably by some other method than a virtual COM port? How do navigational apps on the tablet/smartphone access the NMEA data?

No driver needed,

http://faq.vscom.de/pdf.php?cat=3&id=92&lang=en

Everything you need to learn is in the Manual here http://www.vscom.de/download/multiio...UserManual.pdf

Lloyd

[ebaugh]

I use a very similar device to the one already mentioned. Made by Moxa, but connected by wired ethernet first since my primary Nav computers are all wired. The data is available though via WiFi though since everything is on the same network.

The original configuration is shown in this archive:

http://www.panbo.com/archives/2010/0..._mar_azul.html

There is also some good discussion below the blog post there.

I use the Standard Horizon radio, and since my Cradlepoint router died, I'm now using the TP Link MR3420. I've also added a Bullet 2 HP connected to the WAN port for when 3G is not available and a WiFi connection is.

The trick is picking the mode on the serial device server. The 3 main choices are:

1) serial device emulation which requires a driver under windows
2) TCP server mode
3) UDP server mode

The Moxa only does one mode at a time, but does support multiple connections simultaneously.

With Coastal Explorer I could use TCP server mode. But when I switched to MaxSea for different charts, and at the time, it required serial device emulation which I'm using today. This mode pretty much leaves out IOS or Android devices...I think.

Will answer questions if I can....

[Paul Elliott]

Many programs will connect to a TCP/IP or UDP NMEA stream, without the need to convert it to a virtual serial port. Check the programs you want to use and see if they can connect to a network server.

Shipmodul makes a NMEA multiplexer with a built-in WiFi server, that might do the job for you, but a single serial/WiFi device may do what you need. The Shipmodul mux, and some other serial/WiFi units only provide one server connection. It looks like the VSCOM unit allows multiple network connections. The VSCOM unit does have significant power consumption. Will you want to have multiple WiFi connections to the NMEA data?

[FlyingCloud1937]

Originally Posted by Paul Elliott

Many programs will connect to a TCP/IP or UDP NMEA stream, without the need to convert it to a virtual serial port. Check the programs you want to use and see if they can connect to a network server.

Shipmodul makes a NMEA multiplexer with a built-in WiFi server, that might do the job for you, but a single serial/WiFi device may do what you need. The Shipmodul mux, and some other serial/WiFi units only provide one server connection. It looks like the VSCOM unit allows multiple network connections. The VSCOM unit does have significant power consumption. Will you want to have multiple WiFi connections to the NMEA data?

Not so bad for power hungry, depends on the load

DC 9-30 volt 200-600 mA at 12 volts native.

So depending on load, ie how many devises running. And porting from a multiplexer, then the data stream is refined and buffered.

Lloyd

[xymotic]

Originally Posted by Paul Elliott

It looks like the VSCOM unit allows multiple network connections. The VSCOM unit does have significant power consumption.

It's also quite expensive.

[motu42]

I have been working on this very problem. Ive just put up a working version of 'Freeboard', which uses cheap commodity hardware to provide nav data to anything with a web browser (any browser except IE, which is way behind in HTML5 and websockets).

I have a demo at Freeboard [MeshCMS] Comments would be appreciated

Rob

[FlyingCloud1937]

Originally Posted by xymotic

It's also quite expensive.

$200.00 usd, found online $175.00 usd for a device certified:
FCC Class A, CE Class A, RoHS, IEEE 802.11b/g, RS232, RS422, or RS485.

This is no backyard cook-up.

I paid twice that just for the multi-plexer...so that My 2 Cp's, DS, DSC, and VHF could all talk and listen, so an extra $200 to let all the, pad/smart-phones/laptops also listen in seems cheap. Not to mention that now I can up/Dn load to either CP from any laptop I choose.

Lloyd

[Mollymawk]

Originally Posted by ebaugh

I use a very similar device to the one already mentioned. Made by Moxa, but connected by wired ethernet first since my primary Nav computers are all wired. The data is available though via WiFi though since everything is on the same network.

The original configuration is shown in this archive:

Panbo: The Marine Electronics Weblog: NMEA 0183 over Ethernet, on Mar Azul

Thanks, that's a very interesting article. I hadn't realised there was a potential issue with the radio following the RS232 standard instead of RS422. I'm only just getting into all this; I'd previously thought NMEA0183 was pretty simple and just a case of connecting all the NMEA wires together from the different instruments!

Originally Posted by ebaugh

I use the Standard Horizon radio, and since my Cradlepoint router died, I'm now using the TP Link MR3420. I've also added a Bullet 2 HP connected to the WAN port for when 3G is not available and a WiFi connection is.

Exactly the setup I'm planning when I get back to the boat with my newly bough kit next week.

Originally Posted by ebaugh

The trick is picking the mode on the serial device server. The 3 main choices are:

1) serial device emulation which requires a driver under windows
2) TCP server mode
3) UDP server mode

The Moxa only does one mode at a time, but does support multiple connections simultaneously.

With Coastal Explorer I could use TCP server mode. But when I switched to MaxSea for different charts, and at the time, it required serial device emulation which I'm using today. This mode pretty much leaves out IOS or Android devices...I think.

Interesting. I'm not familiar enough with either NMEA and RS232/RS422 or TCP and UDP protocols to know how this works behind the scenes; but would a basic (cheap) RS232-ethernet device such as this, which "supports" TCP and UDP, be able to do the same thing? I had assumed it was necessary for the device to "understand" NMEA and be able to "translate" it to something it can send over TCP or UDP - but perhaps this is not the case? Maybe any type of data on the serial port would be retransmitted via TCP or UDP without the device having to "understand" it?
Based on what FlyingCloud1937 says, this would seem to be the case, if I'm understanding correctly.


Now, I have another question partly related to this. I'm starting to understand a little more about NMEA0183 and I now see that it's not as simple as I'd previously thought. So what I want to know, is do I need a multiplexer? My only two NMEA talkers are the VHF/AIS and the GPS. Now, both of these are in fact listeners as well. The VHF/AIS obviously wants the GPS position. The VHF isn't going to produce any info the GPS wants to listen to; the GPS listens for things like depth and boat speed which I don't have (or rather I don't have devices with NMEA outputs).
So, with these two devices it would be a simple matter of connecting the NMEA output of one to the NMEA input of the other, and vice-versa. I assume.
But now I want the computer to listen to the outputs of those devices. So how does that work? As I now understand it, this isn't possible without a multiplexer. Is that right?


I have also noticed something else I don't understand (maybe I should be starting another thread, I'm getting a bit off topic here...)
I've just found that the VHF/AIS has two NMEA outputs; one for DSC data (which I'm not too interested in) and a different one for AIS targets (which is what I am interested in). The former is "normal" NMEA0183 at 4800 baud. The latter, however, is something the manual calls "NMEA HS ASI" (is that a typo for AIS, I wonder?) at 38400 baud.
Now, if I want to "listen" to that on the computer, what do I do?
In particular, if I want to listen to both that and the GPS data (obviously NMEA at 4800 baud), what do I do?

Originally Posted by Paul Elliott

Many programs will connect to a TCP/IP or UDP NMEA stream, without the need to convert it to a virtual serial port. Check the programs you want to use and see if they can connect to a network server.

The question really is, do I need a special NMEA multiplexer with ethernet/wifi functionality for this, or will a normal serial-ethernet device do it?

Originally Posted by Paul Elliott

Will you want to have multiple WiFi connections to the NMEA data?

Realistically, probably not. But I like the idea of having the ability to do so.

[ebaugh]

Originally Posted by motu42

I have been working on this very problem. Ive just put up a working version of 'Freeboard', which uses cheap commodity hardware to provide nav data to anything with a web browser (any browser except IE, which is way behind in HTML5 and websockets).

I have a demo at Freeboard [MeshCMS] Comments would be appreciated

Rob

That's pretty neat. Worked on IPad Safari, although I'm unsure if I tested every feature. If your not out of analog inputs you could add engine data too. And a battery amp hour gauge.

How sure are you the hardware will remain easily available? Looks like there is a several week wait for the Pi.

Any plans for vector charts? Not sure how hard that is with a HTTP interface, the strength of the app.

Are you planning to make it open source?

Best Bob

[ebaugh]

Molly...

I'm not sure you will have the same problem with RS422/RS232 I did with the Standard Horizon Radio. They were supposed to fix it to meet the proper standard. Call their tech support and see....

I looked at that inexpensive serial to Ethernet product. It looks like it may work. But I could not tell if it supports multiple TCP or UDP connections simultaneously. Ie two PCs or a PC and an IPad at the same time. It does not have a serial port emulation mode if your PC software won't support TCP or UDP natively. It is also RS232 not RS422. Sometimes that does not matter...maybe someone else can comment. You can find the signaling specs via Google. They are close but not exact. RS422 also provides for multiple listeners.

I do not have a multiplexer. You don't really need one if you have a enough serial ports on your Ethernet gateway. All the software I've seen allows you to define many NMEA inputs and outputs. But depending on what you want to do, most of the multiplexers have RS422/NMEA ports for sources, and provide a RS232 port for a PC....or a single Ethernet gateway, potentially reducing the network interface to a single serial port.

In your case, you need either a mux..or...at least 2 serial ports on your Ethernet server like I have. One for NMEA HS AIS and one for NMEA GPS data. The GPS input to the radio is one of perhaps many listeners, in your case at least gateway and radio. In my case, the single GPS feeds my chartplotter, autopilot, stabilizers, Standard Radio and Ethernet gateway.

DSC is nice to have, but I have not yet implemented it. The power comes at sea where there is a traffic conflict on AIS, then you can (with the right stuff) click on the ship and directly ring them up on VHF, even of they are not maintaining a perfect radio watch. I will add this when I add an AIS transponder eventually and open up the wiring. Was too expensive when I did the original project. Can be done manually via the Standard Horizon radio front panel interface in the meantime.

Hope at least some of that helps. What is your Nav program going to be?

Bob

[xymotic]

Originally Posted by FlyingCloud1937

$200.00 usd, found online $175.00 usd for a device certified:
FCC Class A, CE Class A, RoHS, IEEE 802.11b/g, RS232, RS422, or RS485.

This is no backyard cook-up.

I paid twice that just for the multi-plexer...so that My 2 Cp's, DS, DSC, and VHF could all talk and listen, so an extra $200 to let all the, pad/smart-phones/laptops also listen in seems cheap. Not to mention that now I can up/Dn load to either CP from any laptop I choose.

Lloyd

ShipModul Marine Electronics Yes it's more, (350) but it's a multiplexor AND wifi bridge. Less power, less cost than buying both.

[ebaugh]

I think the Moxa is probably the cheapest solution if you only have 2 sources. Some chartplotters will merge multiple inputs on their outputs. This device:

http://www.neutronusa.com/prod.cfm/286731

Is only $185. And for most people gets enough data on the network. This has 2 RS422 ports, but there is a similar version with one RS232 and one RS422 port. If the Horizon AIS feed is still RS232, this would be the choice for the OP.

I don't want multiple WiFi networks on the ship...one for data combined with Internet when available. Don't think an Ipad or PC can connect to two WiFi nets at the same time. I think a wifi router is a better solution. I also like wired connections for my critical Nav functions which are 2 PCs since I have 2 helm stations.

Even the TP Link MR3420 router is only about 50 bucks now...and it can solve the ships WiFi access and Internet via 3G USB modem or WAN Ethernet port to a Bullet 2 HP (or your choice of WiFi extender).

Total cost under $250, much less than a mux/single port Ethernet gateway....if 2 ports is enough.

[FlyingCloud1937]

My issue was that I have multiple talkers, 6 in total, the mux can listen to up to 8 talkers. It combines everything into one out-put stream, then sends that out, in complete sentences.

The VScom wifi defaults to its rj45 network port, which can then be hard wired into the ships wifi router, but if it doesn't sense a connection on that port it falls over to it's own wifi broadcast.

Give a little redundancy.

Lloyd