By Dermot Tynan, almost 5 years ago.

Carpenters like to say "measure twice, cut once." In the software world, we make extensive use of unit tests and end-to-end tests. But the North Atlantic is no friend to small boats, and there's not a lot of end-to-end testing which can replicate the vagaries of the wild Atlantic. To that end, we use simulations. Simulators can be used to throw all kinds of real-world problems at a piece of software, and measure the response.

  • May 15, 2019
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How to fill a bath

By Dermot Tynan, almost 6 years ago.

It seems straightforward enough to fill a bath. We know how to do it instinctively, but how do we program a computer to do it?

Let’s start with some assumptions. Assume we have a hot and cold tap, and we can control the flow on each tap. Also assume we can measure the average temperature of the water in the bath tub. Finally, assume we can measure the height of water in the bath. This last one is so we know when we’re done.

We’ll denote t as the measured temperature and l as the measured height of water. For that matter, we can refer to h as the amount of hot water, where 0.0 ≤ h ≤ 1.0 and c as the amount of cold water, again in the range 0.0 ≤ c ≤ 1.0.

Ultimately, we’re going to use a PID Controller to do the actual hard work of adjusting the taps. But before we get into that, we need to refine our equations just a bit, and also learn how to walk before we try to start running. (See what I did there? Running? Bath? Oh, never mind).

  • April 3, 2018
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Can an autonomous sailboat cross the Atlantic?

By Dermot Tynan, over 6 years ago.

"Sailing a boat across the Atlantic is challenging enough for a human sailor. But what about a computer? BBC Future visits a sailing regatta for robots."

I'm including a link here for an interesting article published by the BBC on autonomous sailboats.

  • November 20, 2017
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Rudder Movement Test

By Dermot Tynan, almost 7 years ago.

I have uploaded a video (to YouTube) of the rudder mechanism on Hull #1 working from end-stop to end-stop. (Excuse the video quality, I used my phone to record it.)

I connected an Arduino (Mega2560 if you want to know) and a SparkFun stepper controller to the stepper motor which drives the rudder. I wanted to exercise the tiller gears and the rudder shaft for a while. The video shows the rudder swinging from almost completely to Starboard, all the way back to Port.

  • April 27, 2017
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Impending Launch.

By Dermot Tynan, over 7 years ago.

Hull #002 is coming along, slowly. The stations are mounted on the strongback and I've been double-checking the alignment. I have time to do this because 1/32nd inch balsa wood is hard to come by, and because I haven't cut the keelson yet. Well, I have, but I need to re-cut it. The original was cut to the wrong profile.

While the work on hull 2 continues, I've been using Hull #001 to test out aspects of the boat design and control systems. In fact, I am very close to launching the hull…

  • November 1, 2016
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