Good post. Thanks....
I installed OpenCPN
and SignalK on a Pi 2B a number of years ago, back when that was the latest and greatest setup and OpenPlotter wasn't yet available to make things easier. I'm still using the Pi 2B hardware
but did a clean install of the OpenPlotter package on a fresh SD card when upgrading. No more hand editing Linux
scripts and configuration files--much better now!
Like others who have already posted, I get AIS
from a GPX2200 VHF
. I get NMEA183 data for the other usual things like speed, depth
from the old instruments that came with the boat. Everything gets multiplexed and delivered to an assortment of phones and tablets with WiFi, in addition to being directly available to OpenCPN running on the Pi.
Here are a few more thoughts, based on experience:
If you use raster (BSB) charts
, you may not need a Pi with as much processing power as if you use vector (ENC) charts
. At least, I haven't needed to upgrade my Pi 2B and I'm running OpenPlotter successfully on it. In Canada
(CHS) raster charts intended for recreational boating
are inexpensive, whereas vector charts intended for commercial
use are ferociously expensive, to the point that if you want vector charts for a reasonably wide area, a commercial
chart plotter and map card will end up being cheaper. I happen to like those old-fashioned raster charts, so it works OK for me. Your mileage may vary....
Other bits matter even more than the SD card. I've found that the serial-to-USB converters needed to integrate AIS/GPS and instrument data from external sources are the weakest links in the system. A collection of good enough ones to use on a boat cost me more than the Pi. I've used different converters, ranging from super-cheap RS-232 converter chips you can buy by the dozen on Amazon to much better RS-422 converters I bought from Sean D'Epagnier's OpenPlotter store a couple of years ago. This is not something to cheap out on: when the converter fails, you lose GPS
, whatever.... The cheapest ones not only can
fail; they will
fail. Its a question of when not if.
Inadequate power to supply USB devices (and board-mounted hats) is also an insidious gotcha. If you have a recent Pi with enough USB ports
in all your external devices, you need to make sure it has an adequate power supply. If you add an external USB hub to increase the number of inputs to your Pi, that also needs to be powered and the quality of the hub becomes a factor in your system (not all powered hubs are created equal). If OpenPlotter stops receiving GPS and AIS data from your VHF radio
, for example, it could be because the serial
converter failed (see above), or it could just be that the converter isn't getting enough power from the USB port. Problems like this can be frustrating and time-consuming to diagnose.
Even below decks, I've found wetting to be a problem for consumer-grade monitors. I was able to locate the Pi and related bits (USB hub, serial
converters, etc.) in a spot where the boat would have to flood before they would get wet. The monitor
was another matter. The 12V and USB powered monitors you can buy for under $200 on Amazon work
fine until just a little bit of water gets in. Unfortunately, a marine-grade, waterproof touch monitor with a high enough brightness rating to use as a cockpit
display costs much, much more--as much as a commercial chart plotter.
You may not think you need a marine-grade display because your boat is dry enough to use a consumer-grade display down below and you can use a smartphone or tablet in the cockpit
. That used to be my thinking too, but when the old chartplotter
mounted to my steering pedestal
died last year, right before the Lake Ontario
300, I really missed having it, even with OpenPlotter, WiFi and several tablets at my disposal. IMO smart phones and tablets aren't a 100% adequate substitute for a bright, waterproof cockpit display with a hard-wired power supply.
Below decks, as a primary display for the Pi, I tried using a low voltage, USB powered monitor but ended up using a WiFi tablet instead, with VNC installed on it. That let me configure OpenPlotter to run "headless" without an attached, wired monitor and keyboard. There's a hatch
over my nav desk. A leaking hatch
seal allowed a tiny bit of water to drip on the monitor I originally bought on Amazon--just enough in the wrong spot to ruin the monitor, at the dock
, within a week of purchase
. Even down below, I now wouldn't trust anything less than a marine-grade display, or a water and shock protected tablet. Water gets down below--doesn't matter what you do, it happens. All it takes is an open hatch in a sudden downpour, or an off-watch crew member
changing out of soaking wet foulies with the boat pitching and rolling offshore
, and that could be enough to do in the monitor.
Running "headless" used to be a risk. When I first installed the Pi, there were times when, after power to the Pi was switched off without a graceful shutdown, the WiFi interface wouldn't start properly the next time the Pi was rebooted, so the only way to get in and fix it was to attach a wired monitor and keyboard. Happily, I've yet to experience this problem since switching to the latest OpenPlotter release and am increasingly comfortable (a) running headless without a backup monitor and keyboard stowed somewhere safe and (b) not worrying too much about the Pi losing power. I'll even switch it off without shutting it down, sometimes, if I'm at the dock
and I know I can recover the Pi at my leisure if I have to. Not that I recommend it.....
Originally Posted by Dsanduril
We have been using a Pi 3 as our primary navigation
tool for 3 years and one lap around the globe. We run the OpenPlotter install that includes OpenCPN, SignalK, and a bunch of other goodies. PyPilot is on the list of possible upgrades.
Overall we love the Pi and OpenPlotter. A couple of small items:
- Get a really good 5V power supply that is capable of supplying the required current (which varies depending on Pi model). These are cheap (12V-5V) but very necessary. Find one that outputs 5.25V if you can, that is the top end of the Pi spec and allows for some voltage drop.
- Get a really good USB power cable, as short as possible, to connect your Pi to the power supply. USB cables aren't great for supplying power, but there are a few out there with larger power conductors that will help limit the power drop.
- Use a quality SD card.
- Get a decent case for the Pi. This may set you back nearly as much as the unit itself. But the naked Pi board is a bit delicate - put it in a good case. That also helps keep the moisture at bay.
We use OpenCPN to provide routing information, display grib files, drive the autopilot
at the present moment), and just general navigation
We use SignalK to run some web dashboards that allow us to see the instrument values (and some OpenCPN computed data) from tablets connected to WiFi anywhere on the boat. We occasionally also use the built-in VNC server to allow us remote
views of the charts, but for that we usually just turn on the monitor (we normally run with the monitor off to save electricity).
Power usage averages about 4W (~0.33A @ 12V) so about 8Ah/day.
Can't say enough good things about both the hardware
and the software