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One of the first projects I started was back in college when
a friend of mine and I decided it would be fun to start up a small company that manufactured knot meters,
which is a device that measures a boat's speed through the water. I'm not sure why we picked knot meters as the
product of choice other than it was an interesting challenge to measure fluid flow using vortex shedding. We hand prototyped the
circuit board, creating all of the artwork on a drafting board, shooting negatives, and then contact printing the negatives
onto sensitized copper board, which would then be developed and etched. What a miserable and time consuming process that was!
But imagine our delight when the first board was finally assembled and everything worked! I imagine that was more luck at that
point than skill! The knot meter company never did get off the ground, but it gave me valuable experience in what was required
to prototype an electro/mechanical product. |
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The pH probe/amplifier was a quick little project that turned out to be an experiment in DC to DC conversion.
The trickiest part of this project was figuring out a way to boost a 5 volt signal from a communications port to the voltage required to
power a pH probe, while also keeping noise and ripple to a minimum. It functioned well enough, but the project fizzled out never made it
to market. However, techniques improved for prototyping circuit boards and I gained some familiarity with designing for
surface mount devices. |
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The altimeter turned out to be a major project that involved both hardware design,
small signal amplification, machine language programming of microprocessors, and Microsoft Windows programming.
Each of these topics would have been a project in it's own right, but they all managed to converge in one place at one time.
The result was an altimeter that weighs less than an ounce, will record 250 data points, and is programmable for
both gain and acqusition time. At it's highest resolution it's capable of measuring altitude changes on
the order of 1.5 feet. For a short pictorial history of the altimeter development, click on the image to the left
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This is some of what goes into the assembly of the altimeter. Currently these are being hand soldered
under a microscope. It's a little tedious, but manageable at this stage. The next iteration in the production refinement will
be to reflow solder the entire board at once. This requires screen printing techniques to apply solder paste to the board, then
position the components on the board and finally heat the entire assembly to the melting point of the solder. A significant savings
of time...as long as you don't sneeze.
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