Eric's Arcana and RiderX

I saw mommy kissing Santa Claus
Underneath the mistletoe last night.
She didn’t see me creep
down the stairs to have a peep;
She thought that I was tucked up in my bedroom fast asleep

It just doesn’t make sense. There’s no reason for daddy to be wearing a Santa costume. Even if he was picking up a few $$$ on the side at the department store, why wear the costume at home? The kid is asleep. It think it’s mommy’s idea – “he’s asleep now – go put on your Santa costume and you can find out whether I’ve been naughty or nice?”

Then, I saw mommy tickle Santa Claus
Underneath his beard so snowy white;
Oh, what a laugh it would have been
if daddy had only seen
Mommy kissing Santa Claus last night.

Someday you’re going to realize what that “tickle” really was, and I hope you have enough money for the therapy.

The lights got started before Thanksgiving this year – while waiting for a turkey to smoke – but a few weeks of sub-freezing temperatures stalled things because 15 degrees is just too cold to be outside putting up lights.

I had hoped to build something new for this year, but didn’t get started early enough, so the display is mostly the same as last years. I did two upgrades to the tree lights from last year.

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The animation which had worked fine in inside temperatures didn’t work at freezing temps. The processor runs a bit slower at those temps, and it was just enough different to mess up some of the timing loops. That was a simple change.

The second change was to deal with the lack of light. The 2008 version used 7 watt colored lights inside of colored bulbs, and not only was there not enough light, the amount of light differed depending on the color. The 2009 version uses 25 watt and 40 watt lights, so it puts out a bunch more light (about 400 watts total instead of about 100 watts), and the animation works correctly.

I also had to fix ring of fire, which had taken on about a TBSP of water into the circuitry, which made it unhappy. After about 3 hours of troubleshooting showed me that the decoupling capacitor had shorted due to the moisture and was causing a whole bunch of problems.

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So, you’ll need to be content with the write-up from last year, which has a few pictures. I did do a few new pictures. Here’s a picture of the old tree lights:

and here’s the new version (sorry that there’s no snow…)

Full gallery here.

For Thanksgiving this year, in addition to doing our usual turkey (a 20 pounder grilled on the Weber barbecue with apple wood), I decided to do a small one on my cheap electric brinkman smoker.

One of the disadvantages of this smoker is that it doesn’t have any heat control – the electric element is always on. This can cause some problems with temperature control, and there’s no thermostat either.

Wednesday was about 45 degrees, damp, and a bit windy. The guides I looked at said 30-40 min/pound at 225 degrees, which means something like 4-6 hours for my 8 pound bird. I waited until 9AM so that I would be back from my bike ride before it was done. A mixture of apple and mesquite went on for flavoring.

It came off at 9:45 that night.

I think I need some insulation around the smoker to keep the temp up. Or a better smoker…

The turkey, however, was delicious.

Today my daughter and I took a kayak tour, paddled into the wind and against the tide for 45 minutes, and then, while we were resting, happened to see this…

That’s Atlantis rising from historic pad 39A through a 200mm lens from about 10 miles distant (click on image for full-size). The atmosphere was pretty hazy, so the quality isn’t what I had hoped for. The liftoff is a bit strange – all you see initially is some smoke from the main engines (which *only* generate about 1.5 million pounds of thrust), and not a lot of light because they are hydrogen-oxygen and burn clean. *Then* the solids light and throw off a ton of smoke and steam and a ton of light from the incandescent smoke.

A few seconds later, already heading northeast. A bit of explanation is required…

If you have a launch pad on the equator and launch directly east (always east because you get a boost from the earth’s rotation), you would get an orbit that is directly over the equator. If, however, you are in Florida (25 degrees north latitude), when you launch on the most efficient direction, you get an orbit that is inclined to the equator at 25 degrees – the spacecraft will range from 25 degrees north of the equator to 25 degrees south of the equator. This is known as the orbital inclination. Big heavy satellites – such as Hubble – are at this inclination.

To go to a lower inclination is pretty expensive in terms of energy, so this is to be avoided if at all possible. Conversely, it *is* possible (for a reduction in payload) to reach an orbit that is a higher inclination than the latitude of the launch site, all the way up to a polar orbit.

ISS is a joint project with the Russians (among others), and the Russian launch site at Baikonur is at a latitude of 45 degrees, so that’s the minimum inclination for that launch site. That would drop the booster stages on China, so the Russians launch a little more to the north, and ISS is at 51.6 degrees of inclination. The shuttle can hit this inclination for the a reduction of about 30% of payload. This is significant, which is why Columbia (the oldest and heaviest shuttle) didn’t go to ISS.

There are two advantages (to me) of the high inclination. First, it means that ISS travels far enough north on its orbital track to be visible from Seattle. And second, it meant that the track today was northeast, kindof in our direction, so we had better viewing.

This is about 50 seconds into the flight, and at 10 miles, just about the time the sound gets to us. The northeast track means the shuttle isn’t pointed to us and the wind is from the north, so the sound is mostly channeled to the south. We do get a lot of bass out of it, but the most distinctive part is the crackle that it makes. You’ll notice at this point its climbed out of the haze and into the clear sky. I’m pretty pleased that you can see it so well in this shot.

Emerging out of the clouds at around 90 seconds.

At about 120 seconds, 50,000 meters, and 2800 MPH, the solid rocket boosters detach. The 3 main engines make a great searchlight, but produce no smoke and therefore there is no smoke trail. The two dots to the right are the detached boosters.

Overall, it was pretty cool to do, and the vantage point was pretty good. I would have preferred to be on Kennedy, but spots at the 6-mile banana river location are virtually unobtainable, and ones at the Saturn 5 center are impossible for mortals to get.

I can’t say a lot about our guides, “A day away outfitters”. They had more people than they could really handle (53 people with 5 or 6 workers), and missed out on a lot of things that would have made it more memorable. And the husband and wife who own it argued about how they should be doing things in front of their guests.

On February 26, 1962, John Glenn climbed into a Mercury capsule perched atop a slightly-modified Atlas intercontinental missile for a planned orbital flight.

Today, I stood and looked up at that tiny capsule, and marveled at the crudity of the whole thing and the bravery it took to climb into it.

(click on image for larger version. Canon 40D, IS0200, F6.3 @ 1/2000th)

I had an idea a while back.

I’ve noted in my previous article about cadence that riding a slower cadence can be faster. And I’ve been playing around with this on rides, and found that a cadence of about 80 seemed to require less effort at a given heartrate – I can ride at 150 BPM and 80 RPM much easier than 150 BPM and 95 RPM.

But is it a real effect, or am I just imagining it? Well, it’s fairly well documented that fast-twitch fibers are less efficient because they (at least some of them) use anaerobic metabolism, but I’m not sure where the switchover is or if that’s what’s going on.

Time to do a ‘spearment to find out…

The hypotheses

1. At a given heartrate, power output will vary inversely with cadence (ie I will generate more power at a lower cadence than a higher one)
2. At a given heartrate, perceived effort will vary directly with cadence (ie I will feel better at a lower cadence than a higher one)

Experimental method

Ideally, one would use a power meter, but this one doesn’t own a power meter, so I’m going to do it by measuring speed on a hill climb. It won’t give me absolute measurements, but it will give pretty good relative measurements.

The plan is to do repeated hill climbs at various cadences – I’m going to start at 100RPM and go down from there. I’ll to try to to stick around 140BPM, since that heartrate is just a bit below my LT heartrate.

The test

I picked a dry Sunday morning to do the test. I go out and warm up thoroughly, including one climb where I spike my HR up above 160 (if you don’t do this, your results will be less repeatable). I set my Polar (720i) so that it shows cadence and total time (I don’t want to see speed since it might influence me).

I head over to my test hill (NE 8th up from Northup in Bellevue), shift to my lowest gear, and start spinning up at 100RPM. 30 seconds later, I’ve stabilized on the climb – at 70 RPM and 160 BPM. It’s waaaay too steep for this test, but now I’m very warmed up, so I head over to 164th.

I descend to the bottom, stabilizing my HR at 100 BPM, then I turn around and crack up to 100+ RPM and shift and get my HR to 140BPM, and head up the hill. 0.9 miles later I turn off at the top and coast (so I can find the top in my data log), descend and repeat at 90 RPM. Then 80 RPM. Then 70 RPM, and home to read in the data and do some number crunching.

The data

I import the data onto my laptop, and select each section of data. Here’s a table of the data:

The first 4 items are directly from my polar softrware. I used the Bicycle Power Calculator to estimate the wattage.

I’m pretty impressed by the how close I got to my target on both the HR and the cadence.

Here’s a pretty graph:

Perceived exertion

It takes a fair bit of attention to watch your cadence and HR and shift up and down to keep them in the right range as the gradient changes, so I only have my recollections.

The first trial was pretty hard, I was fairly out of breath. The second and third ones got easier. The last one was really hard on the legs and I was a bit toasted at the end.

Discussion

The data quality is better than I expected – you could fit a very nice curve through the points. Going from 103 RPM to 80 RPM increase my wattage 20%, which is a lot more than I expected. Going down to 70 RPM nets me another 7% or so, but I don’t have the leg strength to do it for long. It’s weird that I see an improvement because if I fatigue quickly, I should be falling back more on fast-twitch fibers which should make me less efficient, not more.

On the other hand, I have been working at improving my leg strength which means I’ve been riding a lot at 80 RPM (or lower) on hills in my aerobic zone, so there may be some training effect there.

That’s assuming that HR is a reasonable proxy for energy use, which I believe is true.

So, what does this mean for other people? Not really sure. So go out, give it a try yourself, and let me know what works for you.

If the name “Kevin Smith” rings a bell with you, it’s probably for movies such as “Clerks”, “Mall Rats”, or “Dogma”.

What is less well known is his speaking engagements. Smith travels all over the place to do one-man shows, and last night he played to a nearly packed house at Seattle’s Benaroya Hall.

The format is ostensibly a question and answer format, but the questions are merely an excuse for Smith to tell stories. You might think from Smith’s appearances in his movies – where he is now known for talking – that as an actor, he’s a pretty good writer. You would be wrong – Smith is at the heart a storyteller, and he’s also a very talented performer.

Some questions – where Smith really doesn’t have much to say – yield polite, short answers. Questions where he wants to talk give longer answers – one about what happened after his most recent movie led to a very long (and entertaining) story that took about 45 minutes.

In all, he talked for about 3.5 hours without a break, and was really, really funny the whole time. I should note that Smith doesn’t hold anything back in the topics he covers or the language he uses to express it, and if you are easily offended, this might not be for you.

A DVD of some of his earlier sessions is available. It’s pretty good in its own right, and a good way to tell if the live show is a good fit for you.

The offspring and I spent part of the last weekend at the Seattle Robotics Society’s Robothon 2009. My main involvement in robotics has been having a few friends who were quite adept, and doing a tiny bit of mindstorm programming.

On Saturday, we spent a fair amount of time at the Robo-Magellan competition, which is competition to build vehicle that can autonomously navigate from one orange cone to another. Most of the robots use GPS (WAAS okay, differential not okay), some sort of vision system, contact sensors, and a vision system to identify the cone. A pretty hard problem – out of 6 robots and 3 tries each, there was one successful run.

Watching the competition is a little like golf – lots of people following the robot to see how it’s doing, and clapping when something good happens. At one point, one of the robots came across this scene:

Notice the two kids at the left and right. What do they look like?

That’s right, they look like cones, and the robot attempted to move towards them (at speeds up to 1MPH or so) for a time, and there had to be some readjustment.

The whole idea of building one of these sounds like a very interesting project – integrating software and hardware towards solving a hard problem. I’m somewhat tempted trying to build one…

After the autonomous competition was over, we went back into the center house and watched some robot sumo:

These are really tiny bots – they can’t be more than 10cm on a side, and can’t weigh more than 500 grams (0.00055 tons). The cool thing is that all the robots are autonomous – they all have onboard intelligence (presumably microcontrollers) and sensors. Lots of fun to watch.

Sunday

Sunday we came back to watch some radio-controlled combat vehicles, hosted by Washington Allied Robotics. As much as I like seeing two radio-controlled vehicles try to destroy each other, after a while it pales a bit – looking at their construction, there is chassis, motor, battery, and the radio and drive electronics. An interesting engineering challenge, but not really any code there. But, some have impressive weapons.

I think what we’re seeing here is the titanium spinner of the left bot hitting the titanium front plate of the right one. This is shot through plexiglass, so the quality isn’t great, but I do really like the branching in the left side of the sparks.

Some of the robots can fly:

At least for short periods.

Those are the highlights, but there are a lot of matches that are considerably less exciting. Overall, it’s a lot like watching hydroplane racing – 3 minutes of excitement followed by 30 minutes of waiting.

This past week the parts for my project have shown up. I got a surplus 10A solid-state relay for about $8 on eBay (I’m perplexed why SSRs are so expensive – there are like $2 worth of parts in a $20 part), 12 20W lights, and a substantial 600W transformer from intermatic.

The transformer is actually 2 300W transformers rather than a single 600W one. I wanted to verify that the SSR that I got was working, so I got out one of the lights, carefully wired up the primary of the transformer to an extension cord and the 12V output to the light, and plugged it in.

Flash Snap!

The light got really really bright for a really short period of time, and the snap was circuit breaker tripping.

I’m surprised. It’s pretty hard to mess up hooking up a transformer – there are two AC supply wires, two wires on the transformer, and polarity doesn’t matter. I check my connections and make sure that there are no shorts, and try it again.

Snap!

No flash this time because the light got toasted the first time. I pull out my Fluke Multimeter, set it to resistance, and put it across the primary, where it reads 0.1 Ohms. Same reading across the primary of the second transformer. Let’s see, 120 Volts across .1 ohm = 1200 amps, which makes it pretty obvious why the circuit tripped.

It’s really not as simple as measuring the resistance, since transformers are inductors, and resistance isn’t the same thing as impedance, so I go upstairs to make a sandwich, and do a little thinking. What I need is a way to do some measurements of the transformer with a low-voltage AC current across it. I remember there’s an old trick where you put a bulb inline with the load – that limits the current to what the bulb will pass.

I hook up a 7watt nightlight bulb I use to debug my light projects in line with the transformer, and plug it in. At 7 watts, it pulls 7 / 120 = 58mA of current, which means that (V = IR), it has a resistance of 120 / 0.058 = about 2100 ohms.

A voltmeter on the transformer shows 0.25 volts. That’s pretty low. If 0.25 volts results in 58mA through the transformer, putting a full 120 volts on it would give us a current of 480 * 0.058A = 28 Amps, or about 3300 watts. That’s a lower-end result – I actually think it’s quite a bit worse since 3300 watts would only be a mild overage on the circuit, and that level of current takes a fair bit of time (say, half a second) to trip a breaker. I think it’s more likely that we’re looking at 100 amps or so.

And guess what – the second transformer is exactly the same as the first. Must be a manufacturing defect with some of the windings shorted together.

Last Friday morning, I was sitting at the kitchen table reading the paper, eating breakfast, and listening to music.

My daughter stuck her head around the corner, smiled, looked at me, and said two words:

“Baba O’Reilly”

Which was her way of demonstrating a fairly obscure bit of music knowledge.

Anybody care to explain why I’m proud?