Raspberry Pi / NASA Clipper wireless wind connection

[Sunjammer]

My first quick stab at connecting my Raspberry Pi to a NASA Clipper wireless wind device wasn't successful so, back at the drawing board, I had a thought. Always dangerous, I know. The Mast head unit (MHU) is transmitting a signal which is picked up by the base unit. Could I miss out the middleman (base unit) and use the Raspberry Pi's wireless capability to pick up the data straight from the MHU? I don't know, and it is difficult to find out, what the MHU transmits - is it already an NMEA 0183 sentence or does that get generated at the base station? Would appreciate any thoughts. Am new to the Raspberry Pi (as you can probably tell.)

 

[KompetentKrew]

what the MHU transmits - is it already an NMEA 0183 sentence or does that get generated at the base station?

I bet it's the latter.

 

[Andrew_Trayfoot]

The NASA mast head unit definatly won't be on WiFi frequencies and the receiver box will do the NMEA data generation, otherwise what woukd be the point. Also WiFi would use far too much power.

The receiver box will output NMEA over a RS232 serial connection. Probabily just 2 wires: ground and data out.

To get the data into your Pi you have 2 options:

Direct rs232 wired (you will probabily need a USB to rs232 converter or something else that plugs directly into the Pi to give you a serial port.

Connect the NASA box to a NMEA to WiFi bridge, such as the Yakker or Digital Yacht offerings. Then you can access the NMEA data over WiFi. This is the better, although slightly more expensive option as it gives you the ability to broadcast the NMEA data to any device you choose... Such an an Android tablet for example.

 

[TernVI]

The Nasa website clearly states the masthead unit transmits NMEA data :
MASTHEAD/INTERFACE UNIT SPECIFICATIONS

• Wireless masthead transmitter
• NMEA 0183 4800 Baud
• NMEA data sentence MWV

Unfortunately it does not say what the frequency is or the format, i.e. modulation and encoding.
It must be in one of the 'license free' bands, there are various receivers you can buy for all of these bands to interface to something like a Pi or Arduino, I'm sure it's possbile to bypass the Nasa interface box but it sounds like quite a lot of work for no gain?

Even if it's at the Wifi frequency band, it could be several RF formats, Wfi, Bluetooth, Zigbee etc or some bespoke thing.
The Pi speaks Bluetooth as well as wifi, BT would be a convceivable choice for such a link, so maybe it's possbile to listen with the Pi?
If it is BT, the Bluetooth symbol should be on the unit somewhere?

For a first Pi project, reading the wired NMEA data from the interface box and displaying it, processing it etc with the Pi could be interesting.

 

[KompetentKrew]

The Nasa website clearly states the masthead unit transmits NMEA data :

Not sure which page or model you're looking at, but the one I see says it's the base unit that transmits NMEA, not the masthead unit: "the base unit receives wind speed and direction data from the masthead transmitter and sends it to the Clipper Wind display or any other compatible NMEA display unit."

 

[TernVI]

This one:
Clipper Wireless Wind (Aparrent) - Nasa Marine Instruments

 

[[163233]]

The nasa box communicates over the 433mhz frequency popular with garage doors etc. It says so on the receiver box.

 

[GHA]

Connect the NASA box to a NMEA to WiFi bridge, such as the Yakker or Digital Yacht offerings. Then you can access the NMEA data over WiFi. This is the better, although slightly more expensive option as it gives you the ability to broadcast the NMEA data to any device you choose... Such an an Android tablet for example.

Not quite, routing the data into a raspberry pi allows you do do pretty much whatever you want - send over wifi, record to a database, send over the web if connected, hard to think of anything you'd want to do with data on a boat which can't be done on a raspberry pi.

 

[TernVI]

The nasa box communicates over the 433mhz frequency popular with garage doors etc. It says so on the receiver box.

433MHz receivers are cheap to buy, but th e modulation and encoding could be any one of a number of options, it might be fairly trivial to receive the data and decode, or it might be quite painful.

 

[prv]

If the OP can’t figure out how to connect to the standard NMEA0183 interface provided, it’s ludicrous to suggest that he might be able to reverse engineer the proprietary wireless link instead.

Pete

 

[[163233]]

If the OP can’t figure out how to connect to the standard NMEA0183 interface provided, it’s ludicrous to suggest that he might be able to reverse engineer the proprietary wireless link instead.

Pete

Yes, but it's a much more interesting problem.

 

[TernVI]

If the OP can’t figure out how to connect to the standard NMEA0183 interface provided, it’s ludicrous to suggest that he might be able to reverse engineer the proprietary wireless link instead.

Pete

I don't think it's necessary to be that negative about a beginner having a false start.
There are probably more blogs and articles on the web about connecting 433MHz to the pi than NMEA, so if he's prepared to make the necessary effort to learn, it's very likely possible.

 

[Sunjammer]

Thanks everyone for your very helpful replies. My takeaway from this string is that, given my great age and complete lack of experience with electronics etc, the easier route is to sort the wired linkage from the base unit to the Raspberry Pi. I'm halfway there, got the Pi with a GPS HAT running qtVlm chart plotter software and a USB - RS422 cable to get data in and out. Just had the wires crossed on my first try. Trouble is I can only try it when I get to the boat and, guess what?? Lockdown!

 

[GHA]

Any reason why you went for qtvlm instead of opencpn?
Openplotter is by far the best game in town for the Pi imho, everything you need preinstalled or a mouse click or 2 away.

 

[Sunjammer]

Yeah, I looked at Openplotter too, GHA, and there didn't seem much in it for the limited capablities I needed. When I was checking which charts could be used with Openplotter/OpenCPN for my area (Ireland) it took me to the Visit My Harbour website which was offering the qtVlm package. I've only just got going with qtVlm (been using Navionics on an iPad up to now) so may well give OPenplotter a go at some point. Useful to have your recommendation about Openplotter though, thanks.

 

[GHA]

Yeah, I looked at Openplotter too, GHA, and there didn't seem much in it for the limited capablities I needed. When I was checking which charts could be used with Openplotter/OpenCPN for my area (Ireland) it took me to the Visit My Harbour website which was offering the qtVlm package. I've only just got going with qtVlm (been using Navionics on an iPad up to now) so may well give OPenplotter a go at some point. Useful to have your recommendation about Openplotter though, thanks.

Understood. There are vector charts available, though some people prefer raster, vector runs a little quicker on a Pi, on opencpn anyway. https://o-charts.org/map/en/UK/index.html

I've you're bored one day might well be worth a few quid on a spare sd card and have a play with openplotter, then you could load qtVlm as well, best of both worlds. Openplotter makes it easy to set up the data coming in and sending all the nmea (and other) data over wifi to your ipad.
Downloading — OpenPlotter 2 documentation