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smartcomsoftware

NMEA over Wi-Fi device coming up on Kickstarter

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People may be interested in a project coming up on Kickstarter for a new NMEA0183 to Wi-Fi gateway device.

Have a look at www.nmeatools.com for more information.

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Just so you know I can purchase a RS-422 to WiFi bridge on Amazon for $75 and set it up in a few minutes.    Buy an ad.

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1 hour ago, solosailor said:

Just so you know I can purchase a RS-422 to WiFi bridge on Amazon for $75 and set it up in a few minutes.    Buy an ad.

Link?  I can't find one on Amazon.  This seems like a useful product at a fair price.  Telling some random person to buy an ad is just so annoying and rude.

That said, a MAX3232 and an ESP8266 will set you back maybe $6 so go build one yourself. Oh, there is the box and making it work on a boat.  Personally, if I needed one I would build it but I don't because my RaceBox takes care of what I need.  And don't tell me to go buy an ad because I am not selling anything.  I just give it away.

Allen

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It may do, but the main thing to note is that it is RS232, whereas NMEA is closer to (but not the same as) RS422. Also, there is no mention of it being opto-isolated - this will help eliminate any interference problems, as well as eliminating any ground loops (for these reasons it is required on the receive side in the NMEA spec). If you give it a go, put in an inline fuse as there s no mention of any internal fusing either.

Tim

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NMEA0183 is exactly 422 plus (unnecessary) opto isolation.

There cannot be ground loops as there is no "ground" referencing or ground wire in a 422 connection. It is a self-referenced differential pair. It will work perfectly well with ground shifts as high as about 20V, more than enough for installation on any boat.

The big problem with some NMEA0183 equipment is that the vendors (Garmin, can we talk?) only look at one half of the differential pair and reference it to ground. This eliminates all the inherent advantages of 422 including excellent noise immunity and immunity from modest ground shift. It also introduces ground loops that might be eliminated by opto isolation if they also use opto isolation.

232 is ground referenced and does suffer from introducing ground loops and from signal degradation from ground shifts.

 

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NMEA0183 is close to, but not the same as RS422. The main differences are that the voltage ranges are different (with NMEA allowing a greater range than RS422), and NMEA also allows for single data wires (like Garmin kit) whereas RS422 always requires a signal and ground.

Because NMEA allows single data wires, and also because in implementation quite a lot of 2 wire NMEA connections use ground for B, you can get ground loops and interference problems that you would not generally get with RS422. Also, quite often NMEA wiring is not shielded twisted pair, which again makes it more prone to interference.

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Surely this is a non-starter not a kickstarter? Plenty of devices out there that offer more for about the same price.  Shipmodul being a very decent range of units; for example

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Shipmodule with Wi-Fi starts at €359 (about US$400)

Our device outside of Kickstarter will be £99 (about $125), with the initial ones going for half that in Kickstarter.

Yes, the Shipmodul does more, but it costs significantly more, and not everybody needs that.

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I haven't used the Vesper AIS, but I've looked at the info on the Vesper website for the WatchMate XB-8000.

Obviously the Vesper has a lot of stuff that we don't, but just comparing the common areas of NMEA0183 and Wi-Fi the differences seem to be:

- The Vesper only seems to support a specific number of NMEA0183 sentences for input and output, whereas we just chuck everything through

- We support a couple more data rates for NMEA, e.g. some non-marine GPS devices use 9600bps which we support

- The Vesper Wi-Fi is just TCP, and I'm not sure if the port number can be changed. We support simultaneous TCP and UDP, and everything is configurable. This is handy as some apps just support UDP, whereas others just support TCP.

Please correct me if any of the above is wrong!

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On 5/13/2017 at 10:57 AM, smartcomsoftware said:

People may be interested in a project coming up on Kickstarter for a new NMEA0183 to Wi-Fi gateway device.

Have a look at www.nmeatools.com for more information.

I signed up to get your updates on the device.  I look forward to trying it out as soon as it is offered for sale. 

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12 hours ago, smartcomsoftware said:

I haven't used the Vesper AIS, but I've looked at the info on the Vesper website for the WatchMate XB-8000.

Obviously the Vesper has a lot of stuff that we don't, but just comparing the common areas of NMEA0183 and Wi-Fi the differences seem to be:

- The Vesper only seems to support a specific number of NMEA0183 sentences for input and output, whereas we just chuck everything through

- We support a couple more data rates for NMEA, e.g. some non-marine GPS devices use 9600bps which we support

- The Vesper Wi-Fi is just TCP, and I'm not sure if the port number can be changed. We support simultaneous TCP and UDP, and everything is configurable. This is handy as some apps just support UDP, whereas others just support TCP.

Please correct me if any of the above is wrong!

I don't see the XB as anything near your product. First off it's an AIS transponder, and has it's own independent remote GPS connection. It's also a wifi transmitter, but I don't think it's a good idea to make it your primary wifi connection. A dedicated router, with the XB set to client mode and it's wifi transmitter disabled would be a good idea. It does handle NMEA 0183 thru-put so anything that comes from a multiplexer to the XB, goes through it's own TX. It also supports several NMEA GPS sentence formats, which is handy for devices that need specific sentence format (like my SSB). Personally I think it's a great product, but I can see the need for a simple NMEA 0183 to wifi being a very useful product for people who don't need such a complex boat network.

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1 hour ago, Team Subterfuge said:

I signed up to get your updates on the device.  I look forward to trying it out as soon as it is offered for sale. 

Many thanks

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55 minutes ago, ni·hil·ism said:

I don't see the XB as anything near your product. First off it's an AIS transponder, and has it's own independent remote GPS connection. It's also a wifi transmitter, but I don't think it's a good idea to make it your primary wifi connection. A dedicated router, with the XB set to client mode and it's wifi transmitter disabled would be a good idea. It does handle NMEA 0183 thru-put so anything that comes from a multiplexer to the XB, goes through it's own TX. It also supports several NMEA GPS sentence formats, which is handy for devices that need specific sentence format (like my SSB). Personally I think it's a great product, but I can see the need for a simple NMEA 0183 to wifi being a very useful product for people who don't need such a complex boat network.

Agreed. And there are quite a lot of high end devices that act as a router, do NMEA0183 muliplexing, NME0183/N2K conversion etc that suit some installations but you pay for what you get. We saw a need for a good quality simple, low cost device.

Having worked on marine computing systems since we were putting Apple II's on race boats, and had an early Transit system that filled a berth and gave 3 or 4 fixes a day, I personally would rather stick to good old fashioned wire for primary connections of instruments, but then I'm from the school where a short offshore race set off on Friday afternoon and finished on Sunday afternoon, and if I wanted a short day race I'd go dinghy racing. If you are just having a sprint in a big boat, losing your instruments is less critical for safety, even if it does mess up your race results.

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422 never has a signal and ground. 422 is not ground referenced. NMEA0183 is exactly 422. The NMEA0183 specification describes a hare-brained scheme for working with only one of the two data wires, but that doesn't mean it is not 422.

Further, it does not allow "greater voltages ranges", to quote the NMEA0183 specification:

The maximum applied voltage between signal lines "A" and "B" and between either line and ground shall be in accordance with the EIA-422 specification.

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38 minutes ago, Moonduster said:

422 never has a signal and ground. 422 is not ground referenced. NMEA0183 is exactly 422. The NMEA0183 specification describes a hare-brained scheme for working with only one of the two data wires, but that doesn't mean it is not 422.

Further, it does not allow "greater voltages ranges", to quote the NMEA0183 specification:

The maximum applied voltage between signal lines "A" and "B" and between either line and ground shall be in accordance with the EIA-422 specification.

Moonduster,

I agree - RS422 never has had a signal and a ground. I never said it did.

For new devices the NMEA standard requires RS422 voltage levels, but if you look at section 3.5.3 of the spec it says:

"For reasons of compatibility with equipment designed to earlier versions of this standard, it is noted that the "idle, marking, logical "1", OFF or stop bit state" had previously been defined to be in the range -15 to + 0.5 Volts. The "active, spacing, logical "0", ON or start bit state" was defined to be in the range +4.0 to +15 Volts while sourcing not less than 15 mA."

RS422 is +/-6V

We don't all have the privilege of being able to have the newest instruments.

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For consideration on a future edition - add a NMEA 2000 port and do translation between NMEA 0183 sentences and and NMEA 2000 PGNs.  Kind of like having an Actisense NGW-1 and Wifi all at once.  I recognize the NMEA 2000 requires you to pay a King's ransom to get their specification but there is plenty of open source data on some conversions already done.  Maybe build a library that people can add to for conversions they develop so they can be selectively added to the devices function.

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Yes, we're working on that.Hardware is sorted and we're working towards NMEA type approval, though the inconsistencies in the "standard" and discrepancies between it and NMEA's approval test device is making the software harder work than it should be. Before we started, I though this would be an ideal case for test driven development, but if the tests are wrong then that isn't the case!

The device will be quite configurable, so for most users it will work fine out of the box but there will be the ability to decide which N2K and 0183 sentences are processed and what they map to, and also the sample rate output to NMEA0183 to manage the low bandwidth.

To ensure robustness and compatibility we decided to pay for the N2K docs. Their licence means you have to put the device up for their certification process, and you can't open source the code. However we're thinking about how we can use our learning curve to offer a service to other small developers in implementing N2K, within the licence constraints of NMEA.

The aim is to have a t least a pre-production device ready for METS in November.

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Now you're arguing with yourself.

To quote your post #8, emphasis added:

NMEA0183 is close to, but not the same as RS422. The main differences are that the voltage ranges are different (with NMEA allowing a greater range than RS422), and NMEA also allows for single data wires (like Garmin kit) whereas RS422 always requires a signal and ground.

You certainly did say that 422 has a ground. And your repeated claims that it can be the cause of ground loops implies it has a ground. It has no ground and, therefore, cannot cause ground loops.

You're similarly mistaken about the meaning of NMEA0183-3.5.3, which isn't about talkers sourcing those voltage levels, it requires that listeners be tolerant of them. 422 requires ±10V, a swing of 20V, while the NMEA is looking for single-ended tolerance of 15V. It's a proper subset.

NMEA0183 is exactly 422.

 

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Tacktick says it is nmea-0183.  It works fine with RS-232 line drivers and receivers and will not work with RS-422.  I think many people put nmea-0183 devices into laptops so there is that as well.  Also, my Stowe displays are three wire, Rx, Tx and Ground.  It is not a clean standard.

RS-422 can work up to 1500 meters.  Overkill on a boat.  With a device that is a bridge to WiFi, the cable is probably very short indeed so it probably just doesn't matter.

 

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The actual NMEA 0183 standard is explicit re: the PHY.   There are non-conforming implementations.  There is no certification program to verify conformance to the spec.

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Just to let people know that the project is going live on Kickstarter tomorrow (the 31st) at 0800PDT / 1100 EDT.

There will be a limited number available for just £50/$65 each.

As soon as it goes live there will be a link to the Kickstarter page from www.nmeatools.com

Tim

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