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Posts tagged video

Hands-On Engineering

It seems the more little engineering projects I do to support my photography habit, the more I find I want to do.

Last year, it was the double-header, and the time-lapse rig for the Iceland roadtrip. But after looking at some of this guy’s work and the toys he created to do it, I got hooked on the idea of a motion-control dolly.  I figured, I’m a mechanical engineer, right? How hard can it be?

Well, following his example seems to be a lot more difficult in the U.S. than in Germany. Finding the exact motors he used and an equivalent Igus slide were trivially easy, but finding gears and a gear rack to match have been frustratingly difficult — so much so that I’m giving in and ordering them from the same company he used, and hoping that the shipping and whatever import duties this entails balance out against the higher prices and half-assed selection offered by McMaster-Carr and other similar retail gear suppliers here.

The Igus slide arrived yesterday, and I was disappointed to discover that my mental impression of a meter corresponds more closely with four feet than three. But other than that, it’s a slick and simple piece of engineering:
Slide

The most fun part of all of this, however, came from digging into the motion control aspects. Ben’s setup used a simple voltage regulator to control the speed, but I quickly discovered there are better ways — specifically, using Arduino microcontroller components. It would appear that if you have anything that moves or needs to be monitored (or both), there are Arduino boards which can be adapted for the purpose — right up to navigating autopilots for DIY drones. And it’s all dirt-cheap.

I think this is going to be a fun little project, with lots of learning transferable to related follow-on projects (why stop at one axis of motion?).

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Driving Lessons

This is the same video the rental agency in Iceland made us watch before they would hand over the keys.

If driver’s education here were as graphic as the segment on seatbelts at 4:38, I’m guessing we’d have a lot fewer traffic deaths.

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Science Eye-Candy

High-speed video of droplets of liquid nitrogen rolling across a hot surface, demonstrating something we’ve all seen while cooking but probably didn’t know had a name — the Leidenfrost Effect:

From Wikipedia:

The effect can be seen as drops of water are sprinkled into a pan at various times while it is heating up. Initially, as the temperature of the pan is below 100 °C (212 °F), the water just flattens out and slowly evaporates. As the temperature of the pan goes above 100 °C (212 °F), the water drops hiss on touching the pan and evaporate relatively quickly. Later, as the temperature goes past the Leidenfrost point, the Leidenfrost effect comes into play. On contact the droplets of water do not evaporate away so quickly. This time, they bunch up into small balls of water and skitter around, lasting much longer than when the temperature of the pan was much lower. This effect lasts until a much higher temperature causes any further drops of water to evaporate too quickly to cause this effect.

This works because, at temperatures above the Leidenfrost point, when water touches the hot plate, the bottom part of the water vaporizes immediately on contact. The resulting gas actually suspends the rest of the water droplet just above it, preventing any further direct contact between the liquid water and the hot plate and dramatically slowing down further heat transfer between them. This also results in the drop being able to skid around the pan on the layer of gas just under it

[via Eileen]

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Real Gubernatorial Genius

…is in short supply in Colorado this year, but Todd and Justin at Complete Colorado are at least having some fun with the unfunny situation.

Republican (sigh) Walter Mitty, Dan Maes:

Democrat (meh) Denver mayor, John Hickenlooper:

American Constitutional Party’s former Republican, former congressman, former presidential candidate, and evergreen lightning rod, Tom Tancredo:

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Final Stimulus Package – Breaking a Few Eggs

Amanda from Liberty on the Rocks explains the effects of the ongoing orgy of government bailouts and stimulus packages and pork spending:

For those in Denver, be sure to check out the coverage of today’s anti-stimulus rally at the Capitol steps on Peoples Press Collective.  The rally will take place between 12:15pm and 2:00pm, and will feature Michelle Malkin, Bob Beauprez, Jim Pfaff, and others.

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