Bidirectional Multiplexer

Discussion and support for the Nmea2Wifi multiplexer
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Luis Sa
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Posts: 39
Joined: Thu May 04, 2017 4:12 am

Bidirectional Multiplexer

Post by Luis Sa » Tue Sep 12, 2017 11:19 pm


I am releasing firmware version 4.0 of the NMEA2WIFI multiplexer. In this version you can:

1) Send through the serial output port data received by wifi. With this facility you can, for example, control your autopilot using your smartphone

2) Select the data streams that pass through the multiplexer. For example, you can choose serial input port 1 or serial port 2 or both to be transmitted through wifi. Also you select what is output on serial port P#3 (any combination of inputs P#1, P#2 or Wifi). In version 3.0 you only had the options of: Serial Out = ON or OFF; Wifi Out = ON or OFF

If you do not need any of these improvements, you should go on with version 3.0. If you want to try this new firmware you should download the file NMEA2WIFIV40.bin and use the method explained in the previous post of this forum.

When this new firmware is fully tested, new units will be dispatched with it. You can see here the user settings page for the new version.

Note: I released NMEA2WIFIV41.bin which version 4.1 of the firmware. If you have version 4.0 you do not need this new version unless you need to test the operation of the Nmea 183 serial ports as described here.

Regards, Luis

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Joined: Tue Sep 05, 2017 4:41 am

Re: Bidirectional Multiplexer

Post by zigakusar » Tue Oct 03, 2017 8:42 pm

I have made extensive test with new firmware. First at my home with electronic used on my sailboat, and then also at sea.
My setup is:
- NMEA2WIFI (nmea to wifi converter)
- Daisy AIS (AIS receiver, connected via RS-232 TTL built-in interface to NMEA2WIFI on P2)
- Humminbird Matrix 17 with GPS (Fishfinder with serial GPS receiver, connected via RS-232 interfaceto NMEA2WIFI on P1)
- Raymarine ST1000+ autopilot (NMEA autopilot, connected via RS-232 interface to NMEA2WIFI on P3)
- OpenCPN on android smartphone

I have left home test running couple of times. The longest test takes 2 complete days. And I didn't found any issue. The system was stable and reliable all the time.
I have also run a test on my sailboat. Duration of this test was 2 hours without any problem.

With NMEA2WIFI I have advantages:
- Now I have redundancy. If my GPS connected to Fishfinder stop working, I can use GPS on my smartphone.
- If navigation on my Fishfinder stop working, I can drive autopilot from Open CPN on android smartphone.
- If the weather is bad, I have all essential data on my smartphone too.
- I can use andhor alarm and AIS radar on smartphone - that is not supported on my Humminbird.

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Joined: Tue Jan 02, 2018 6:19 pm

Re: Bidirectional Multiplexer

Post by JohnH » Wed Jan 03, 2018 3:56 pm

I am delighted with this device, and have tried the test mode and accessing via a tablet, though with no data.

Before visiting the boat and connecting to existing instrumentation (Raymarine, very like the schematic depicted in the SeaTalk-NG topic), it would be useful to have simulated data for testing the setup with a WiFi client device.
Is there any chance you could add a test mode with simulated transmission of one or more parameters such as Depth?
This would allow testing with the Navionics Boating app over WiFi connection.
Or can you suggest simulation software and a simple adapter circuit for a PC with serial port?

For your information I also use Marine Navigator on an Android device, and hope to view live AIS data in future - in the meantime I'm happy with your recommendation of SeaWi which seems very useful except for the basic charts.

Luis Sa
Site Admin
Posts: 39
Joined: Thu May 04, 2017 4:12 am

Re: Bidirectional Multiplexer

Post by Luis Sa » Sat Jan 06, 2018 5:33 pm

Hello John,

Thank you for the suggestion which is most appreciated. Yes it can be done as it is only software. The easier way for me to do that is to add a check box in the main (and single) web page interface . It could be called "Simulation Mode". If the box is checked, the multiplexer would ignore the 2 Nmea 183 entry ports and the wifi UDP receiving ports independently of these particular settings. Instead it would read from its EPROM memory preloaded Nmea 183 sentences and would transmit them through the wifi port at a predefined (and fixed) rate.

If you or someone reading this wants to supply me a set of Nmea sentences (may one for GPS position, one for depth, one for wind speed and direction, one for temperature and two or three for AIS vessels) I could integrate this future in a new firmware version.

Best Regards, Luis

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