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Old 18-01-2020, 20:03   #61
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Re: Raspberry Pi as Onboard Computer

rs422 is a way to have a high speed link over longer distances and be immune to interference, but it's questionable if it is needed on cruising boats. I think it's more useful for ships and industrial systems.

38400 is very slow compared to the 10mbit rate that rs422 can support as it is using single wires (not differential) but this is ok for our purposes. For anything requiring more bandwidth like radar or cameras needs to use ethernet or wifi anyway.

gps, ais, depth and wind can all fit on a single 38400 stream

3.3v ttl uart signals will work at 38400 baud at 100ft or more on unshielded cable. This is maybe "out of spec" but I know from experience that it works at least using the raspberry pi uart on gpio pins... try it. It might be an issue if there is interference, but typically there isn't on our boats.

If the cable is shielded and the rx and tx are both twisted with ground wires, it will work over hundreds of feet using only 3.3v ttl signal at 38400 baud.
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Old 19-01-2020, 06:07   #62
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Re: Raspberry Pi as Onboard Computer

Quote:
Originally Posted by boat_alexandra View Post
rs422 is a way to have a high speed link over longer distances and be immune to interference, but it's questionable if it is needed on cruising boats. I think it's more useful for ships and industrial systems.

38400 is very slow compared to the 10mbit rate that rs422 can support as it is using single wires (not differential) but this is ok for our purposes. For anything requiring more bandwidth like radar or cameras needs to use ethernet or wifi anyway.

gps, ais, depth and wind can all fit on a single 38400 stream

3.3v ttl uart signals will work at 38400 baud at 100ft or more on unshielded cable. This is maybe "out of spec" but I know from experience that it works at least using the raspberry pi uart on gpio pins... try it. It might be an issue if there is interference, but typically there isn't on our boats.

If the cable is shielded and the rx and tx are both twisted with ground wires, it will work over hundreds of feet using only 3.3v ttl signal at 38400 baud.
Okay, Thanks.

So something like this (see link) USB to RS422 should work to bring in the NMEA Data from my Standard Horizon GX2200 VHF/AIS/GPS to the Raspberry Pi USB connection? Says it will work with Windows, Mac, etc but doesn't mention the Raspberry

It (the GX2200) has the 6 small output wires yellow, brown, green, white, and the 2 others.

https://www.commfront.com/products/u...ant=9208938115

or

https://www.usbgear.com/USB-RS422-AT.html

I'm just experimenting at this point to see what I can get out of one of these Raspberry Pi 4 computers then go from there.

I do plan to load up the charts I need from OpenCPN onto it also
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Old 19-01-2020, 06:16   #63
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Re: Raspberry Pi as Onboard Computer

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Okay, Thanks.

So something like this (see link) USB to RS422 should work to bring in the NMEA Data from my Standard Horizon GX2200 VHF/AIS/GPS to the Raspberry Pi USB connection? They don't mention the Operating system for the Raspberry though

It has the 6 small output wires yellow, brown, green, white, and the 2 others.

https://www.commfront.com/products/u...ant=9208938115

or

https://www.usbgear.com/USB-RS422-AT.html

I'm just experimenting at this point to see what I can get out of one of these Raspberry Pi 4 computers then go from there.

I do plan to load up the charts I need from OpenCPN onto it also

These are an example of all you need. Cheap, but work fine.
https://www.ebay.com/itm/Industrial-...wAAOSwp41bIz79
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Old 19-01-2020, 06:18   #64
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Re: Raspberry Pi as Onboard Computer

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Makes the Pi look neater too, without the dongles hanging off the back of it. My Pi is velcro'd to the top of the VHF so without the extension leads, it would look fugly!
That seems like a good idea. I haven't yet appreciated/fully grasped how small one of these things is
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Old 19-01-2020, 06:23   #65
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Re: Raspberry Pi as Onboard Computer

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These are an example of all you need. Cheap, but work fine.
https://www.ebay.com/itm/Industrial-...wAAOSwp41bIz79
Perfect! I like cheap.

I'm guessing these things will be labeled A, B, X, Y, shield for the wire connections like the connection guide I found online.

Probably standard...….

I could mount this at the VHF/GPS/AIS then get a USB adapter/extender to bring it down to the Raspberry Pi which would be right below
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Old 19-01-2020, 06:59   #66
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Re: Raspberry Pi as Onboard Computer

Hello, for couple dollars you could make your own Seatalk conversion here:
Berreizeta: SEATALK - ARDUINO BI-DIRECCIONAL ADAPTER
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Old 19-01-2020, 08:08   #67
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Re: Raspberry Pi as Onboard Computer

As well you could see at Thomas Knauf:
Thomas Knauf ¬*¬*¬*¬*SeaTalk Technical Reference
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Old 19-01-2020, 08:20   #68
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Re: Raspberry Pi as Onboard Computer

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As well you could see at Thomas Knauf:
Thomas Knauf ¬*¬*¬*¬*SeaTalk Technical Reference
Very nice.

You don't get to see simple electronics circuits on schematics much anymore.....
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Old 19-01-2020, 09:48   #69
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Re: Raspberry Pi as Onboard Computer

I'm using a Pi4 with USB-Can device (About Ä70) and a cheap USB GPS receiver. I also have GPS via my AIS and Chartplotter all fed into the Pi. I don't bother with NMEA0183 It's antiquated IMO.

The Pi4 is a massive improvement. I found the 3B+ to be pathetic in terms of smooth scrolling, zooming in OpenCPN whenever there is any detail or activity happening. The Pi4 copes well enough.

I was initially using an SSD, but it's bulky then for my wall-based installation so switched to an SD card. The Sandisk Extreme 32 U3 V30 was the fastest in my tests, and is A1 rates for use with apps that are doing multiple small writes frequently.

Slightly slower was the Samsung Evo Plus. Both worth well.

Display-wise I use a IIyama Pro-Lite 10". This has 1000nits brightness and is touch screen, and a very well featured monitor. It is let down in a few areas though. Due to the brightness, the colour accuracy is poor. Ok it's not going to be used for photo editing or anything, but still. The minimum brightness is ever-so-slightly too bright for serious night work. That being said I came into my last anchorage at night in string winds using it so avoid reefs. Finally, the touch display is only multi-touch in Windows, Linux drivers support only mouse mode.
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Old 19-01-2020, 14:39   #70
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Re: Raspberry Pi as Onboard Computer

So I'm hoping to use an HD Tv as the monitor for the Pi.

It has two HDMI input jacks.
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Old 19-01-2020, 15:19   #71
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Re: Raspberry Pi as Onboard Computer

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So I'm hoping to use an HD Tv as the monitor for the Pi.

It has two HDMI input jacks.

That works no problem, just check your HD TV is actually 1920 x 1080 pixels in the specs. Some have lower resolution displays. This is ok, but not the best for viewing at the "normal" distances you would view a monitor.
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Old 19-01-2020, 15:44   #72
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Re: Raspberry Pi as Onboard Computer

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That works no problem, just check your HD TV is actually 1920 x 1080 pixels in the specs. Some have lower resolution displays. This is ok, but not the best for viewing at the "normal" distances you would view a monitor.
Yeah, it's a bit large. The Raspberry Pi 4b I bought a little while ago is updating now.

I think I'll keep it (the 19" TV) though for the boat as it was only $80.00, but I'll probably get a better monitor soon maybe a touchscreen monitor which would make things easier on the boat.

I'll just need to get an antenna for the tv

Soon as it updates, I'll try to get on here as a test.

I'm very surprised at how easy it was to setup. very nice.

I did worry about not having an ESD strap though, but it seems to be ok.

Also, I'm sure your average guy never uses one.
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Old 19-01-2020, 16:34   #73
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Re: Raspberry Pi as Onboard Computer

This thing is too cool for school, but this display reminds me of one of my earlier computers.

Plus I bought this cheap keyboard and mouse which is probably a good idea as it will be treated pretty rough onboard the boat

A decent touch screen monitor will definitely be a nice upgrade
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Old 19-01-2020, 16:55   #74
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Re: Raspberry Pi as Onboard Computer

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This thing is too cool for school, but this display reminds me of one of my earlier computers.

Plus I bought this cheap keyboard and mouse which is probably a good idea as it will be treated pretty rough onboard the boat

A decent touch screen monitor will definitely be a nice upgrade
Found a 15in LCD touchscreen yesterday for under $150 new, cleared my browser history now I can't find it.
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Old 19-01-2020, 17:43   #75
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Re: Raspberry Pi as Onboard Computer

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Found a 15in LCD touchscreen yesterday for under $150 new, cleared my browser history now I can't find it.
I waited too long to edit
I have found numerous 12v touchscreens but the largest I can find is 13in. Amazon has the 15.6in 5v usb-c powered for $169. Found it somewhere for $148 but it's hiding from me.
As for the Pi 4, when my wife found out it would be here next week she said ,"Thank You, and if it works well maybe you should buy yourself one, too"
I didn't even get to open the box yet
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