Gas station without pumps

2020 April 1

Document cameras becoming unavailable

Filed under: Circuits course — gasstationwithoutpumps @ 15:29
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I decided to get a document camera for making video mini-lectures, as I suspect we may be doing at least part of Fall quarter on-line.  Based on recommendations from colleagues, I decided to get the IPEVO VZ-R camera, which I ordered last night.  Delivery was predicted to be in 3–4 weeks (it would have been another week, if I’d opted for free delivery).  If I had been in a hurry, I could have ordered the same camera from an Ebay store for another $75, with “free and fast” delivery by next week.

Both Amazon and Ebay stores seem to be out of stock today, so I probably ordered at the last possible moment.

Because I won’t have a document camera for another 3 weeks, I can’t start making videos right away, but I can set up my “studio” space, plan which topics I’ll talk about, and maybe even try writing some scripts. I’ll also have to get some colored calligraphy markers and practice writing and drawing with them, so that I don’t scrawl illegibly on my first few videos.

Just cleaning up the book room in the garage to be the studio space will be a 3-week project, as it will mean clearing a 20-year accumulation of materials from the top of my desk.  Clearing the floor and the sofa will take even more effort, as my wife has commandeered the book room for doing her job, so everything is covered with children’s books, book covers, due-date pockets, and the other paraphernalia of a children’s librarian.  We’ll also have to take turns using the desktop machine, as it is the only one with a big enough screen for video editing or even photo editing, and she needs it for her school-library blog as much as I do for creating mini-lectures.

I may end up having to get a second desktop computer and setting up the studio in the bedroom rather than the book room—that will take even more time to clean up. Though the accumulation is of shorter duration, it is denser and with fewer places to put things away.


Best visualizations of the COVID-19 spread

Filed under: Uncategorized — gasstationwithoutpumps @ 10:03
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This is a followup on my post Exponential and logistic growth, which was intended mainly as as teaching opportunity for showing the value of log scales on graphs.

In the comments, Miguel Aznar pointed to videos from MinutePhysics ( and TomRocksMaths (, and whatisron pointed to and

The best static visualization I’ve seen is at, which allows you to choose log or linear y-axis scales, plotting confirmed case, active cases, new cases/day, deaths, or recoveries, and (most importantly) having a choice of plotting either raw numbers or normalized by population size.  The normalization by population size is important for comparing efficacy of different approaches, as the total numbers mainly tell you how big the country or state is, and now how much of an impact the COVID-19 pandemic is having.  All the plots have time on the x axis, but start the clock at different times for different countries or states, with time=0 being where the case count=20, death count=5, case rate=1/million, or death rate=1/million.  One could probably get a denser clustering of the curves by being more sophisticated about the definition of time=0, but this method has the advantage of simplicity.  Another nice feature of this visualization is that you can choose which country or state to highlight, so you can, for example highlight your own state to see how it compares with the cloud of others.

Some very interesting outliers are the countries with very slow spread (Taiwan and Japan), or initial rapid spread followed by shutting down the spread (China and South Korea).  Iraq has har fairly slow spread, but Spain and Turkey have had extremely rapid spread.  The United States has pretty much been following Italy’s curve for confirmed cases, but fortunately not for deaths (Italy is at over 200 deaths per million and has not plateaued yet).  Spain and Belgium have had the fastest growth in per-capita deaths, and Spain may still overtake Italy—both are at the point where their health-care capacities are exceeded.  Taiwan and Japan have been so successful at slowing the spread of cases that they don’t even appear on the death plots, not having reached the 1 death/million threshold that the graph makers were using.

If the US reaches 200 deaths/million (as seems likely given how we are following Italy’s curve for per-capita cases, we can expect to see 66,000 deaths in the US.  Since Italy’s death toll is still going up fairly rapidly, and there is currently no evidence that the US is doing any better than Italy at slowing the spread of COVID-19, we can probably expect 2–3 times that death toll (consistent with the optimistic scenarios from the US government).

At the state level, New York, Michigan, and New Jersey  stand out for very rapid growth of cases and of deaths (so it isn’t just more testing).  Oregon and Vermont stand out for slow growth of deaths.  California is low for confirmed cases per capita, but middle of the pack for deaths per capita, so California is probably way behind on testing.

2020 March 31

Forty-third weight progress report

Filed under: Uncategorized — gasstationwithoutpumps @ 14:55
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This post is yet another weight progress report, continuing the previous one, part of a long series since I started in January 2015.

This year is not going as well as last year.

I’m about 5 pounds heavier than the same time last year.

I’ve been doing a lot of stress snacking lately, and staying home to do grading really resulted in my weight going up.  Without the discipline of bicycling up to campus every day (and skipping lunch most days), my weight has not only stopped going down, but started up again.

I  averaged only 2.8 miles/day of bicycling in March, down from 4.83 miles/day in February, and 5.13 miles/day in January.  My walking is also down: my Verily study watch from Project Baseline reports 117k steps for March (3900/day) down from 190k steps for February (about 6600/day) and 240k steps for January (about 7700/day).

I’m going to take a walk today (wearing my COVID-19 mask) to get in a little exercise. I’m also going to have to come up with some way to motivate myself to exercise more—not just for this cower-in-place period, but longer term, so that I can continue even after retirement.

COVID-19 mask

Filed under: Uncategorized — gasstationwithoutpumps @ 14:40
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On Sunday, I sewed myself a mask for when I need to go out to the store.  I used a pattern from Tiana’s Closet, which seemed to me almost the same as many others on the web.  I modified it in one major way—replacing the elastic with ties that go behind the head (using some 30-year-old bias tape that my wife had).

The results look a bit sinister:

I think I’ll make the next one out of a more cheerful fabric.

Flattening and reinforcing the curved seam was a little harder than I expected (it has been a long time since I sewed anything curved), but not too bad.

There was one problem with the mask design—the part that covers the nose does not fit tightly to the nose, leaving a gap between the nose and the cheek. This means that exhaled breath goes up through the gap and fogs my glasses.

Here is a closeup of the gap under my eye.

I’m not sure how to redesign the mask to avoid that gap. Commercial N95 masks (of which I have a handful from last year’s fire season) use a strip of soft metal to pinch the mask tight around the nose. I tried using some soft 12-gauge copper wire to make a nose clip, but I was not able to make one that helped.

Does anyone have a pattern that works well for big European noses? Or suggestions for ways to avoid or close the gap?

2020 March 29

Recycled writing

Filed under: Uncategorized — gasstationwithoutpumps @ 08:32
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I’ve been reading a lot of coronavirus coverage on the Associated Press, and I’m getting very tired of seeing the same paragraph buried somewhere in every article:

For most people, the coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. But for others, especially older adults and people with existing health problems, the virus can cause more severe illness, including pneumonia, and lead to death.

This must have been a mandate from the AP administrators—surely the reporters themselves would have been more varied in how they presented the information, even if they were plagiarizing each other.

Perhaps the AP administrators could loosen the reins a little and let their reporters and editors determine the content?

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