Broadcasting NMEA/SeaTalk data on a wireless network

[Four Suns]

I posted this in the Mac vs. PC thread but it'll get buried over there. Has anyone added or used some of the NMEA multiplexer devices that broadcast your Nav instrument data out on BlueTooth or Wi-Fi for laptops and handhelds to pick up on/around the boat? Things like:

http://www.marinewireless.us/

or

http://www.shipmodul.com/en/miniplex-42bt.html

Seems like a great way to get data like waypoints, running data, etc. to/from a laptop...

 

[Pirate]

Geez, Gary- I was going to make fun of you for being such a geek, but I will want to know how that stuff works after you try it so I'll be quiet.

Don't get any fingers in that propeller on your hat or you'll fall to the ground.

 

[Sea Gull]

I like the bluetooth device better than the wifi one.

I already run a wifi network on the boat for internet access and printer sharing. Having a second wifi access point for nav data wouldn't really work for me. But, the bluetooth device would allow computers and handhelds to get the nav data (which maybe could be shared over the ship's wifi system).

All that said, I kind of like having the computer system running a completely separate navigation setup with its own gps. That way it is a back up if the primary system fails.

I also have the output of one of my E-120 displays connected to the salon tv, as a dumb monitor. I am still trying to figure out how to distribute that signal so that I could also see the same info on the other tv sets at the same time.

 

[wkearney99]

To distribute the chartplotter picture you could use an RF modulator and a distribution amp. Are you taking VGA out of the chartplotter or just composite video? I can't recall what the E-series outputs. If it's VGA then you could use a PC-to-TV adapter that converts the VGA to composite video. The resolution on the chart plotter isn't too high for conversion to TV. There will be a little bit of 'pixel jump' for fine lines but otherwise it'll be fine. Then take the composite video signal and put it through an RF modulator. Use a cheap one and put it on channel 3 or 4. Or get a Channel Master and select whatever station you'd like. Use a distribution amp and/or splitter to bridge it into the existing antenna connection to the TVs. Then just tune the TVs to that channel. The picture will be 'good enough' for most purposes.

If the other TVs also have VGA input then you can get a VGA distribution amp to split the signal and boost it enough to drive multiple displays.

Then get the Seatalk keyboard and you can control the chart plotter from anywhere else on the boat you wire up the keyboard.

 

[wkearney99]

I don't know that many of the bluetooth devices support being used by multiple hosts. As in, you can't share a bluetooth device the same way you'd share something on WiFi/ethernet.

The raymarine stuff is ethernet. I've used a hub (not a switch) and the wireshark software to watch the packet traffic. Not sure how well, if at all, it handles being forwarded over wifi.

What's common to do is have one computer on the network 'host' the GPS data and act as a network server to the others. I can't recall who makes it but there is a software gateway designed specifically for this. That and some COM port emulation drivers for the client machines.

Personally, there's far too much free time in the winter to scheme up these ideas. Then once the season starts and you're out on the water there's NO TIME to actually bother using them. I've got all sorts of geek options on the boat and, frankly, never use 'em.

 

[Four Suns]

All that said, I kind of like having the computer system running a completely separate navigation setup with its own gps. That way it is a back up if the primary system fails.

My boat computer (the one I have permanently installed on the boat with a Nauticomp display) is also a complete separate system in case the primary fails. I took it one step further though in that I used an NMEA multiplexer that can do automatic failover from the GPS. That way, I have consistent GPS and waypoint readings and if a GPS unit fails, the second one kicks in.

My interest in broadcasting the NMEA and SeaTalk data is so I can pick it up on my laptop (like from the weather station on the hardtop) at 3 am and don't have to go turn on the equipment on the bridge but can do it from the cozy-ness of my bed... Geez... I'm not lazy... really....

 

[Four Suns]

I already run a wifi network on the boat for internet access and printer sharing. Having a second wifi access point for nav data wouldn't really work for me. But, the bluetooth device would allow computers and handhelds to get the nav data (which maybe could be shared over the ship's wifi system).

On the wi-fi side, I was thinking more along the lines of some kind of device that would have an IP address and use the existing network and just broadcast NMEA data over a TCP/IP port (pick some unused port like "3047" or something). The software on the laptop/PC/PDA then allows you to connect to the IP address on the network and specify the port number where the broadcast is happening.... Some of the Nav software allows this already so you are essentially using your existing network/Internet setup. The thing about that kind of setup is a greater range than Bluetooth.

 

[wkearney99]

On my winter 'to do' list is fiddling with something that'll give me a web server view of boat data. I've got a spare laptop and I'm mucking around with using it as a 'hub' for monitoring various boat systems. I can interface to the Raymarine gear via an RS-232 to SeaTalk bridge. I can also pickup some of the ethernet chatter between the weather box and the E-80 (but it's not easily decoded). I'd probably run remote desktop or VNC on this box to allow remote control over it from other PCs or my PDA cell phone.

My initial plan is to just use it to monitor temperature, bilge pump activity and available shore power. I'd like to know if/when the power goes out during a really cold spell. I've winterized the boat so it's not like it'd really matter. But some sort of warning would at least afford me the chance to get in touch with someone more local to the boat to perhaps deal with any potential problems.