At sea - Embedded.com

At sea

Dateline: 28 07N, 68 23W, 350 nautical miles south of Bermuda, 1000 miles east of Florida

In the 70s I bought a 40-year-old wooden sailboat for a pittance. Though at first little more that a floating assembly of wooden boards moored in near proximity to each other, a couple of years of part-time work restored her to near-pristine condition.

I replaced the 2,080 screws that held her hull together, the deck, the keel bolts, and far more. Eventually, flush with all of $1,500 and the optimism of youth, Arwen and I headed south from Maryland to sail around the world.

Though Arwen’s purchase and refitting had all been financed by my job as an embedded systems engineer, the boat had nary a single microprocessor on board. In those days stereos, such as they were, used analog tuners. The depth sounder was a piece of lead on a marked line, heaved frantically overboard only when the water looked thin.

Even the EPIRB–an emergency radio transmitter that emitted a warble on aircraft distress frequencies–used but a bit of analog circuitry. Not enough, it turned out, to be effective when a container north of Cuba left me drifting in a liferaft. Low tech flares saved the day.

How things have changed. My current boat, built in the same (1977) year Arwen and I left for points unknown, fairly bristles with antenna and electronic systems. As I write this in mid-ocean, a thousand miles east of Florida, bound for the island of Grand Turk, an 8051 in Voyager’s autopilot steers.

Only my wife and I are aboard so it’s nearly impossible to keep a watch all the time, so the radar sweeps silently all night long, emitting a beep whenever a target intrudes within a 10-mile guard zone. The beep is too quiet to alert these sleeping ears, so I’ve tied the radar into a network. A PIC-based box extracts the beep message and sounds a klaxon. The GPS passes position data back to the radar screen; when a ship appears it takes but a moment to place the cursor over the dot and get the vessel’s exact position.

The ham radio’s DSP enhances weak signals. Our marine VHF radio scans multiple channels constantly. A digital battery monitor displays the state of charge of the twin 6-volt golf cart cells, and a similarly-smart voltage regulator generates four different kinds of charging regimes to keep the batteries topped off. The utterly-essential Dell MP3 player (fondly christened a “DellPod”) feeds 2,500 sounds from its hard disk to a smart stereo.

Most astonishing of all is the GPS. It’s a small unit, bulkhead-mounted, that constantly shows our position with an accuracy of meters. Once navigation was an arcane art, kept secret by ships’ officers so crews couldn’t take the risk of mutiny. Now I turn the unit on at the start of the voyage and do nothing more than watch our position update each second. What Captain Cook would have given for such powerful magic!

Oddly, though, the charts are still crude, many of these remote islands based on surveys from the 19th century. It’s ironic that the cheap little GPS is far more accurate than the charts produced at great government expense.

On Arwen I navigated with a sextant, a slice of antiquity that accurately measures angles. Given the angle between the sun or a star and the horizon, plus the time, a bit of math produces a line of position. But there’s quite a bit of skill required, and even the best navigators are happy with a mile or two of error. Clouds thwart any sextant sight; over the centuries hundreds of ships and thousands of lives have been lost due to simple math errors and dank, dismal skies.

Today that same sextant lives over Voyager’s chart table. I shot the sun and Jupiter yesterday, and reassured Marybeth that the GPS is still working correctly. One wag suggested putting it behind a glass case with a sign “break glass in case GPS fails.” But the fact is one can now buy a dozen GPS devices for the cost of one good sextant. The technology has truly rendered celestial navigation obsolete.

Poor winds have had us motoring far too much. Voyager’s three decade-old diesel is mercifully processor-free, but I’ve been thinking about building a simple two wire network of epoxy-coated CPUs and sensors to monitor its health.

In the 1,500 miles since we left Baltimore the autopilot chewed up a belt. One cabinet latch failed. Fish ate two lures. The engine is leaking just a bit of oil and might need an injector replacement. The anchor light burned out, and one sail needs a bit of attention. But every bit of electronics works flawlessly.

I often rant about the state of the embedded art. Too many systems are unreliable and bug-ridden. Yet even on the anachronism of a sailboat, our lives are improved and coddled by processor wizardry.

One report suggested that the average home has over 200 micros today. Embedded systems are the glue that holds the 21st century together. Frustratingly, few non-techies know what the word “embedded” even means, despite their utter reliance on an implanted pacemaker or smart coffee-maker.

It seems there’s always an anti-technology backlash. People move back to the land. They reject the power of science; some yearn for Walden Pond. Me, I embrace the sort of life our smart electronics has created. How about you?

Jack G. Ganssle is a lecturer and consultant on embedded development issues. He conducts seminars on embedded systems and helps companies with their embedded challenges. Contact him at . His website is .

Reader Response


I take issue with but one statement in this column:

“Oddly, though, the charts are still crude, many of these remote islands based on surveys from the 19th century. It's ironic that the cheap little GPS is far more accurate than the charts produced at great government expense.”

While your GPS receiver might be cheap, I would be very surprised if the sum cost of producing all maritime charts in the 19th century approaches the cost of deploying (and maintaining) the GPS satellite network for the last 30 years (it is difficult to determine the cost of initially deploying the constellation since it was a military project, but maintenance has run around $400M USD per year since 1978 for a total maintenance expenditure to date of around $10B USD).

So while the GPS is indeed more accurate than the 19th century charts, it was provided (as common sense would dictate) at *greater* government expense than the older charts.

There's no such thing as a free lunch Jack; remember this the next time you pay your federal income taxes (which is what actually provided the accurate position data you speak so fondly of – not the $49.95 you paid for the receiver :-).

– Rennie Allen
S/W Engineer


Jack,
I agree — the embedded technology has made many things a whole lot easier. The big problem we all face is what we do when (if?) the technology fails. I was just reading recently about a problem with a lot of new (and some old) airplane pilots, who, because of the accuracy and simplicity of GPS, have not developed their “dead reckoning” skills sufficiently. When the GPS occasionally fails, they're in trouble. The solution, of course, is redundancy. The electronics are so cheap, you can have two or three of something as backups. It would be hard to go back to slide rules and sextants!

– Dave Telling


I just wanted to tell you that I appreciate you sharing your gift for writing. You paint a wonderful mental picture and it is a pleasure to read your articles. I am an up-and-coming embedded systems programmer and your articles are inspiring. May the seas be calm and the wind be at your back 🙂

– Steve Broderick


I think that you have exactly the right attitude. Embedded micros do an incredible amount of such a small cost. The 'on the mark' part is that you are aware of what they do, what their shortcomings are, and what your options are if they fail.

– Steve Nordhaus


Your conclusion regarding the proliferation of embedded systems in our world leads my thoughts back to an earlier article of yours regarding certification of software developers. Your GPS could easily provide a location that was in error by a few hundred metres (perhaps causing you to run aground), due to a software error, and you would be none the wiser. Even a redundant GPS from the same manufacturer would likely carry the same flaw, so calibrating one against the other would be useless.

The general masses who blindly trust technology (for their pacemakers, ABS brakes, toaster ovens, etc.) are at the mercy of an uncertified “profession” who face no professional repercussion for a product created with questionable ethical input, where cost and schedule become more important than public safety.

– Diane Farish



Jack,
Be it sextant or GPS, man has always been dependent on technology. And this has probably challenged man of his natural survival abilities. One of them I would refer to is abilities like what the lobster has developed by using magnetism (
“Lobsters Navigate by Magnetism, Study Says, ” by Brian Handwerk for National Geographic News, January 6, 2003) instead of using GPS or a compass.

You talked about pilots not having adequate “dead reckoning” skills. Let me point out shamelessly that nowadays, I find myself struggling to do even simple math without a calculator or a computer (I spend most of my time in front of my comp)!

Being so much dependent on technology–shouldn't we also try to embrace tendencies of developing our natural abilities (though we do need enough patience!)?

– Saravanan T S
Specialist
TEL


I agree, Jack, that technology is pervading our lives and gives us more comfort and ease of operations. But we must also be very judicial in applying it only where necessary. It brings to mind a joke that did the rounds during the cold war years–that the Americans spent a million dollars to design a fountain pen that could work in outer space's gravity-free environment, but the Russians just used a pencil!! So, although older technology may have its drawbacks, it made people wiser to use their own gut knowledge, too, in times of failure.

– Chary BS
Software Architect
Philips


“It's ironic that the cheap little GPS is far more accurate than thecharts produced at great government expense.”

The charts were most likely (re)produced at zero government expense by apublishing house. The govt produced the underlying content at great expense.

The little GPS receiver was produced at zero govt expense. The govt producedthe infrastructure upon which its operation depends at *significant* cost. Theconstellation itself has cost ~$4B to build and launch; this doesn't includeoperational costs or the costs of developing its predecessor systems.

I wonder if you'd have GPS on your boat if it had been developed under a purelycommercial model, such that you had to pay for the underlying development andoperational costs through a *much* more expensive receiver plus monthly servicefees.

– Doug Caldwell


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