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Discussion Starter #1
Hello SailNet community!

Is anyone aware of an NMEA2000 to Bluetooth converter? I've seen TakeFive's excellent thread about something similar for NMEA0183, but not NMEA2000.

Such a device would let you receive sensor data, including GPS, on your iPad or Android device, for example.

There are NMEA2000 to WiFi devices on the market (from SeaSmart for example), but they are all in the $500 or more price range. Also, Bluetooth seems like a better choice on a boat (the range is fine and the power consumption is lower than WiFi). Here is a comparison of WiFi vs. Bluetooth:
Bluetooth vs. Wi-Fi Power Consumption | Science - Opposing Views

If nothing turns up, would anyone be interested in developing such a device together with me?

NMEA0183 with Bluetooth thread:
http://www.sailnet.com/forums/elect...s-nmea-data-chart-plotter-over-bluetooth.html

Thanks.

P.S. This is my first post!
 

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Welcome to Sailnet!

I think that the idea has merits to connect to a battery powered MFD. However, many NMEA 2000 devices get their power from the NMEA 2000 cable... Adding BlueTooth to a transducer, for example, would still require you to run a cable for power.
 

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Hello SailNet community!

Is anyone aware of an NMEA2000 to Bluetooth converter? I've seen TakeFive's excellent thread about something similar for NMEA0183, but not NMEA2000.

Such a device would let you receive sensor data, including GPS, on your iPad or Android device, for example.

There are NMEA2000 to WiFi devices on the market (from SeaSmart for example), but they are all in the $500 or more price range. Also, Bluetooth seems like a better choice on a boat (the range is fine and the power consumption is lower than WiFi). Here is a comparison of WiFi vs. Bluetooth:
Bluetooth vs. Wi-Fi Power Consumption | Science - Opposing Views

If nothing turns up, would anyone be interested in developing such a device together with me?

NMEA0183 with Bluetooth thread:
http://www.sailnet.com/forums/elect...s-nmea-data-chart-plotter-over-bluetooth.html

Thanks.

P.S. This is my first post!
I've never used NMEA2k, and know very little about it. But what I've read indicates that it is a more network oriented bus topology, and the bandwidth is much higher - enough so that I would worry about Bluetooth COM port emulation not being able to keep up. I suspect those two things are why WiFi is a better match than Bluetooth for NMEA2k.

If you're concerned about the high power demand of WiFi routers, there may be a few options. Windows running on your laptop has ad hoc network capability, though I'm not sure whether it includes DHCP address assignment, or if it merely shares an existing IP address from a central router. Some Android phones have tethering enabled with DHCP capability, and I know that mine WILL assign IP addresses and looks just like an ordinary router to client computers and tablets. Finally, the ZyXEL MWR102 travel router can be found for around $25 and runs off of USB power (<500 mA @ 5V). All three of these options would provide WiFi running off a battery, or at least plugged into the boat's 12V system at very low power consumption.

Sorry, I can't do anything about the $500+ cost of NMEA2k to WiFi converters. Since NMEA2k is based on an automotive standard, maybe there are non-marine WiFi converters at lower cost. For instance, perhaps you can find a device that will plug into the OBDII port of a car and transmit the data via WiFi, and adapt it for marine use with a plug conversion.
 

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Discussion Starter #4
eherlihy, I'll keep that in mind. I was thinking the device would connect to the NMEA 2000 trunk and get power from it just like the other devices. As far as I understand it, all the NMEA 2000 data should be available there unless you have some sort of firewall setup. Connecting the device to power shouldn't be too bad if it needs more than can be supplied by the trunk.

TakeFive, that's a good point about bandwidth. I spent some time looking into this and it seems like Bluetooth, including Bluetooth low energy (the one I'm interested in) should be able to handle it, though it would be pretty close to its limits. NMEA 2000 operates at 250kbit/s [1], so the theoretical throughput is at most that, though probably lower. Bluetooth classic operates at 1-3Mbit/s though the application throughput is much lower, at 0.7-2.1Mbit/s [2]. The application throughput for Bluetooth low energy, the one I'm interested in, is lower still, but just enough, at 0.27Mbit/s (276.48kbit/s) [2].

Following your suggestion, I looked for devices like this for cars and there are several that run over bluetooth [3], which is promising.

[1] NMEA 2000 - Wikipedia, the free encyclopedia
[2] Bluetooth low energy - Wikipedia, the free encyclopedia
[3] Bluetooth Adapters - Torque OBD2 Wiki
 
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