Tag Archives: living aboard

The Power of Raspberry Pi: over reaching and hitting the wall

Posted on by under anchoring, living aboard, misc, Systems, Weather

For background, see the previous post here. At this point, the Raspberry Pi (RPI) has proven itself aboard Schooner Mahdee by reliably logging data from our Airmar weather station plus other boat data and displaying that data on an HDMI monitor, as well as monitoring that data and sounding alarms as required. We built in the capability for more than one computer to read the Airmar weather/boat data from the RPI network port at the same time. To realize that potential, we needed a Wifi access point. A USB Wifi dongle, supporting the access point protocol, with the right software (in our case HostAPD) turned the RPI into an access point for all Mahdee users. A good access point provides some basic network services that were set up on the RPI–such as IP address assignment DHCP server–and is a domain name server (we used Bind9 server) for all the Wifi-connected computers aboard the boat.

Raspberry Pi and Cat

Further adding to the roles for the RPI, I wanted to be able to read email without turning on any other computer, so we needed to set up internet access on the RPI. We set up the RPI to use either a Sprint phone with a data tethering plan using PPP or our Verizon Wifi hotspot using a second USB Wifi dongle. Since Brenda’s Windows 8 machine can’t tether directly to the Sprint phone, we decided to make the RPI Mahdee’s internet gateway that can be switched between either Sprint or Verizon. That also meant a better firewall setup for the RPI.

The RPI doesn’t have a hardware clock (by design it would rely on an internet connection to set the time on boot), so when we rebooted the RPI, sans-internet, in the middle of nowhere in Alaska, the data logger had the wrong time stamps. To fix that, we setup a USB puck GPS as a time source for the RPI. This meant also running a GPS position server on the RPI which is then available on a network port of the RPI for other computers aboard Mahdee. The fast high resolution GPS data was also setup to be used by a Python anchor watch and position alarm which I’d previously written for the Nokia N810. The sound system on the RPI is not very good nor very loud even with our USB powered amplified speakers.  For the alarms we setup a piezo-electric buzzer which is energized by a RPI GPIO port so that we can hear alarms anywhere aboard the boat. The RPI also uses GPS time stamps to provide a network time basis for other computers aboard.

With the 2TB Passport hard drive attached to the RPI, it only made sense to put a copy of our public file archive on it and thereby make it available to us 24-7. The public file archive includes repair manuals in PDF form for most boat systems (nice to have in an emergency), all of our photos as well as digital books and magazines (nice for passage entertainment). This nicety meant putting PDF and e-book readers on the RPI. Then, to enable access to those files from Windows computers, we setup a Samba server which also requires a network time server. Fortunately we already had the GPS-based network time server on the RPI.

To enable us to read our email when there is no internet connection available, we setup the RPI with OfflineIMAP to sync mail from our main email server (an off-boat/shore-based virtual private server) whenever we have internet access. I read email using Mutt which can run in a terminal on the RPI. Brenda likes to access email using SquirrelMail webmail via her computer’s web browser, so we added an Apache2 web server to the RPI along with Squirrel Mail and an IMAP server.

In among the public archive data is our music collection, so we setup RPI as a network music player. On those long passages, we thought it would be nice to listen to music, but this is where things start to break down. The poor, now very overloaded, RPI just couldn’t make the music sound even decent. I also setup my Bluetooth stereo headset on RPI, but that was even worse than listening to broken up music through the speakers.

Many boaters want their RPI to run a navigation program like OpenCPN. I had managed to compile a version of OpenCPN on our first RPI, but running OpenCPN required all the resources of the RPI and I was not willing to forego all the other important roles our RPI was needed for–simply to use OpenCPN as a backup chart plotter.  Our real chart plotter is used to display radar and chart data including charts for other countries without free official charts (like Canada). Not needing to run OpenCPN helped a little with our overloaded RPI situation.

From the RPI GUI interface, I found web browsing to be very slow and unproductive. I could get email and read it using Mutt just fine, but there was other trouble lurking. Brenda informed me that basic web access from her computer through the RPI Wifi access point was way too slow. I tried it using my main computer and had trouble too. I had had hopes–fantasies perhaps–that RPI would also run a contact and calendar web service. Most people would just use Google for this, but we are often not near internet access and besides, who really wants to trust the big guys with all of your sensitive contacts and scheduling. But, it was not to be–at least not yet.  Stay tuned for the next installment in this series of posts about the RPI and how we turned the corner towards success.

Skipping up the Coast

Posted on by under food, living aboard, Weather, Wooden Boats

David looking at charts

After lazing about for the day and watching the big surf hit shores at San Simeon, at 6 pm on Saturday afternoon, we set out up the coast to pass Point Sur in the night.  On our trip down the coast last fall, we had a rolling sled ride down past Point Sur with high winds over 20 kts, short and steep waves, and overall conditions that I’d not want to be motoring against going up the coast.  I was nervous on this trip since the weather forecast by NOAA and other forecasting services last fall for our passing of Point Sur was for no wind but yet we had much!  This time, the forecast was also for very little wind (2-6 kts with a few bouts of 10-15 kts) so I kept my fingers crossed.  This time, all was well and good.  We motor sailed into less than 5 knots the entire way passing Point Sur around 2:30 in the morning.  We decided to bypass Monterrey and continue on to Pillar Point Harbor at Half Moon Bay.  We dropped the hook in the harbor just past noon.

We sat back and watched the holiday antics of many boaters nearby.  Pillar Point is an enjoyable place to be.  New things include the newly restored Monterrey Clipper fishing boat that seemed to be ferrying tourists around the harbor.  We know the fellow who worked on the restoration so we’re hopeful to go and track him down sometime before we depart the harbor and talk to him about the successful project.  Several cruising boats were in for the holiday weekend including a very large aluminum hulled boat with three children aboard and a life-sized skeleton hanging on a noose above the transom.  Nice boat, poor taste in decor.  The small boat center seemed to have kayaking classes ongoing and we were visited by a family in a wooden outrigger canoe.  All-in-all a nice afternoon of bay-watching.

This morning, we’re still lazing about.  It’s chilly so I’m sitting in our chart house bed with the down comforter all puffy around me.  Heavenly.  However, we are likely to have visitors since people (yes, strangers) often stop in and ask questions about Mahdee when we visit a new harbor, so I’d best put away the bed and make things “decent” here in the chart house. I’m really enjoying cooking on our gimbaled Taylors kerosene stove.  We purchased the stove a few months ago from a friend (he had found an even nicer kero stove for his boat) and now we have the ability to cook huge meals on the wood/coal Shipmate or use the Taylors while underway or for smaller fare–like breakfast this morning!

Fair winds,

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