Gas station without pumps

2016 January 31

Thirteenth weight progress report

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This post continues the series of weight progress reports from the previous one. Even after I adjusted my target weight range, to gradually relax the upper limit and allow it to increase at 0.6 lbs a year, I’ve still fallen outside the target range several times this month.

At the end of the month,I barely made it into my target range, and I still want to lose about 3 pounds.

At the end of the month, I barely made it into my target range, and I still want to lose about 3 pounds.

My exercise for January was fairly high (averaging 4.9 miles/day bicycling), and I was pretty good about my raw-fruits-and-vegetables-for-lunch diet.  But there were several faculty recruiting and grad student recruiting dinners, at which I ate too much high-calorie food.  There are still three more faculty recruiting dinners in February, so I’ll need to watch myself.

If I could bring back the strict discipline I had last year at this time, I could lose the remaining three pounds in three weeks, but it is hard for me to stop snacking and to leave the supper table before I feel full—I did it for 5 months last year, but I’m finding it more difficult this year.


2016 January 27

Good deed thwarted

Filed under: Uncategorized — gasstationwithoutpumps @ 10:55
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I got an email a few weeks ago, announcing a blood drive on campus.  It has been a few years since I gave blood—the last time I signed up for a blood drive, I got a bad cold and had to cancel. Several other blood drives I’d had to skip because they were scheduled on days when I had no spare time. When I was a grad student, I gave blood fairly frequently (3 or 4 times a year), but there was a Red Cross blood donation center near the Stanford campus, so I could schedule donations at my convenience, not waiting for a blood drive. It is much, much less convenient here, where there are only one or two blood drives a year.

I figured it was past time to give blood again, and so I signed up for an appointment, scheduled for 10:30 this morning.  I picked the time as a compromise between having to get up extra early and my afternoon scheduled classes and appointment.  Also, by the time I signed up, it was one of two appointment times left.

Yesterday, I got scheduled for an extra meeting about the design of a new course for 11:30 this morning, but I figured there was just time to give blood, recover for half an hour and make it to the meeting.

I got up a little early this morning, so that I could drink the extra 16 ounces (475ml) of liquid that they requested, and cycled up the hill to the Stevenson Event Center where the blood drive was located. I was 10 minutes early for the appointment, and feeling pretty good—I was actually going to be able to give blood this year!

Before I signed in, though, the man at the sign-in table warned me that they were running an hour behind schedule (that’s right, by 10:30 in the morning, they were already an hour behind schedule). So the slot that I had available for the blood drive was not, in fact available.

What is the point of Red Cross scheduling appointments for a blood drive, if they aren’t going to keep to their schedule?

I can understand having a first-come-first-served system, with no appointments.  I can understand an appointment system where every slot for giving blood is scheduled ahead of time.  I can understand having an appointment system and taking walk-ins when there is a spare station available and no one with an appointment waiting.

I can’t understand having a system that takes appointments then makes the people who have appointments wait an hour.  That is just incompetent scheduling.  Either they should have made fewer appointments, or they should have asked the walk-ins to wait.

I had to leave without giving blood, and I’m irritated with the incompetence of the Red Cross blood drive.  It may be several years before I attempt to give blood again, because it is clear that I’ll have to dedicate at least 2 and possibly 3 hours (to compensate for their incompetence at scheduling), rather than just one hour.

Perhaps the reason that there is a perennial shortage of blood donors in the US isn’t because people are unwilling to give, but because those who collect the blood are incompetently managed.

2016 January 21

Santa Cruz Shakespeare—Oregon Shakespeare

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Santa Cruz Shakespeare (SCS) is organizing a trip to Ashland to see the Oregon Shakespeare Festival (OSF) before the SCS season starts. It sounds like fun, but …

  • The trip is March 16–March 19, 2016, at the end of exam week, with grades due on March 22.
  • It costs $1250 a person (a bit high for a bus trip, 3 plays, and 3 nights of hotel—a lot more than the AFE trips my son took that saw 4–5 plays and several workshops).
  • Deposits have to be made before Feb 6.
  • They are going all that way by bus and then only seeing 3 plays.
  • My wife is not excited by the plays they plan to see:
    • an adaptation of Glibert and Sullivan’s Yeoman of the Guard
    • Twelfth Night
    • Great Expectations

I must confess, I’m not particularly excited by those choices either. Yeoman of the Guard is not the best of G&S, and I’ve no idea what OSF is doing in the adaptation. Adding country music does not sound appealing to me.

I think my wife and I both like Twelfth Night, but my wife is afraid that I’ll be comparing it to a performance that I saw in Berkeley when I was a grad student at Stanford (so almost 40 years ago). That performance included the a capella group Oak, Ash, and Thorn singing all the songs that are alluded to in the script (there are a lot of them), in addition to good acting and staging. I doubt I’ll ever see as good a Twelfth Night again. What amazes me is that the band is still together and still (sometimes) performing in the Bay Area.  (Hey, maybe Santa Cruz Shakespeare could hire them to do a great Twelfth Night performance!)

Great Expectations is not my favorite Dickens story (actually, I’m not sure I have a favorite Dickens story—it’s been a long time since I’ve read any of them).

Of course, so early in the season OSF only has 4 plays running (the SCS trip doesn’t include River Bride, which seemed the most interesting of the 4 plays running early.  Later on the OSF season gets more varied and more interesting, but SCS will be in rehearsal or production then, and unable to run a tour bus up to Ashland.

Maybe some year SCS will do the trip during UCSC’s spring break and OSF’s first plays of the season will be more enticing—then my wife and I might find the prospect more alluring (though going up later in the season, when it would be possible to see a wider variety of plays, is still more appealing).

2016 January 19

Reading switches with ADC

Filed under: Uncategorized — gasstationwithoutpumps @ 22:49
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Circuit for reading 4 switches.

Circuit for reading 4 switches.

It is often necessary to read the pattern of a large number of switches using few pins on a microcontroller—this problem came up for my son and me in planning to read 9 switches of a DIP switch for setting a DMX-512 address on theater lighting.  There are many ways to do this, but I’ll only talk about one today—using an analog input to read a voltage provided by a voltage divider.

In the circuit to the right, each switch can be open (1) or closed (0). The resistance of the pulldown is the sum of the resistances associated with each switch, and the voltage is Rsum/(Rup+Rsum) Vdd.

To make this work, all the pulldown resistors must be different, so that each combination of switches makes a different voltage. We want to make sure that the values are all easily distinguished by the analog-to-digital converter of the microcontroller, even with worst-case tolerances of the resistors and noise on the ADC input.

I wrote a little python program to optimize the values for different number of switches, selecting optimal thresholds and measuring how close the worst-case resistance values come to the thresholds. I used only standard resistor values from either the E48 series or the E24 series, all with 1% tolerance, and assumed that the ADC had either a 10-bit resolution (like Arduinos) or a 16-bit resolution (like Teensys).  The resolution matters, because the thresholds are integers, and so rounding may reduce the tolerance for noise when the ideal threshold is halfway between integers.

E48 resistor series, 1% tolerance. 10-bit DAC

pulldowns pullup minimum distance to threshold
 1,1.62  1.62 58.322
 1,1.87, 3.48  6.49 19.772
1,1.96, 3.83, 7.5  14.7 7.187
 1, 2.05, 4.02, 7.87, 16.2  30.1 2.016

E48 resistor series, 1% tolerance. 16-bit DAC

pulldowns pullup minimum distance to threshold
 1,1.62  1.62 3704.975
 1,1.87, 3.48  5.9 1239.316
 1,1.96, 3.83, 7.5  14 430.585
 1, 2.05, 4.02, 7.87, 16.2  31.6 103.930

E24 resistor series, 1% 10-bit ADC

pulldowns pullup minimum distance to threshold
 1, 1.6  1.5  56.952
 1, 2, 3.6  4.7 18.586
 1, 2, 3.9, 7.5  12 6.993
 1, 2, 3.9, 8.2, 16  33 1.804

E24 resistor series, 1% 16-bit ADC

pulldowns pullup minimum distance to threshold
 1, 1.6  1.5   3644.94
 1, 2, 3.6  6.2  1181.525
 1, 2, 3.9, 7.5  13  425.540
 1, 2, 3.9, 8.2, 16  27 103.065

Note that a 10-bit DAC with ±2LSB of noise can decode 5 switches only with the E48 series—the E24 series does not allow values to be tweaked sufficiently (and ±2LSB on a 10-bit ADC is unusually low noise—it probably isn’t safe to put more than 4 switches on a 10-bit ADC). A 16-bit ADC with <±100LSB of noise should be able to decode 5 switches with no trouble.

I was not able to find a 6-switch solution with 1% tolerance resistors, even assuming a high-precision ADC.


2016 January 18

Theatrical weekend

Filed under: Uncategorized — gasstationwithoutpumps @ 19:59
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This weekend has been a busy one for me—I went to three different theatrical performances:

Saturday night: 8 tens @ 8
Each year, the Actors’ Theatre puts on a show consisting of 8 10-minute one-act plays, which they select from submitted manuscripts.  (I wrote a little of the history in 8 Tens @ 8 in 2016). My wife and I went to see the A show on Saturday night—we’ll go to the B show in a couple of weeks.  The plays were not all of equal quality—not in the writing, not in the directing, and not in the acting.
Our favorite of the A show was You Too, by Tim Woods, directed by Scott Kravitz.  The lines were good, the characters believable, and acting and directing spot-on.
Also excellent was A Shared View, by Mary Caroline Rogers, directed by Audrey Stanley.  The script was a little less strong, but the acting and directing were excellent (both MarNae Taylor and Marcus Cato were well cast).  Good Medicine by Rod McFadden was fun, but very predictable. Flirting with Age, by Jack Spagnola (the only author without a blurb in the program), was a pretty predictable farce, but we enjoyed seeing MarNae in a very different role than she had in A Shared View. It is always a good idea to end with a farce (or at least a comedy), so that people leave feeling good about the show. Flirting with Age was a good choice for this position (though Good Medicine might also have worked, it wasn’t quite as fun).  
Threatened Panda Fights Back was too silly for the somewhat serious theme of extinction—the costuming was fun, but I was not otherwise impressed with the play. The Italian Prisoner by Paul Lewis had directorial problems (the singer was much too loud relative to memory of the boy Joey Rosen), the acting was a bit wooden, and the script too obviously borrowing from Tosca. Following Ms. Sergeant was a good effort with a rather flawed script—the sudden confessional mood seemed out of character for both characters, and the resolution too forced. Janis Gives Comfort was trying to handle “death and sex” as a theme in a nostalgic vein, but it didn’t resonate at all with me—perhaps I just didn’t care enough about Janis Joplin, who the main character was obsessed with.
Sunday morning: Winter’s Tale
The Del Mar Theater had the broadcast of Shakespeare’s Winter’s Tale performed by the Kenneth Branagh Theatre Company from the Garrick Theatre.  The Winter’s Tale is not often performed, because it is a somewhat muddled combination of a number of themes (jealousy, young lovers in disguise, rustic merriment, …) better handled in other plays. Branagh assigned himself the choice role of Leontes, but then over-acted the part. OK, it isn’t the subtlest part Shakespeare ever wrote, but it doesn’t call for crumpling up on the stage with stomach cramps all the time.  Setting the initial scene at a Victorian Christmas party exchanging token presents also seemed rather forced. Judi Dench as Paulina was very good, though, and the dancing in the rustic scenes quite impressive (if a little more balletic than country).  It was worth going to see The Winter’s Tale, but there’s no reason be sad if you missed it.
The Del Mar had put the broadcast in one of their small upstairs theaters, which sold out—I think that there was a high-school class getting credit for attendance. It would have been better in the larger theater downstairs.  But the Del Mar was definitely the right theater to show the broadcast in, as it has the closest that Santa Cruz gets to the gilt plaster ornamentation of the Garrick Theatre.
Sunday evening: Neil Gaiman’s Graveyard
West Performing Arts did a theatrical performance of Neil Gaiman’s Graveyard, using only 6 actors (5 female, 1 male) and 3 musicians. The actors were fairly young (middle school or early high school, I think). One review on a homeschool mailing list said “Very different from everything else I’ve seen going on locally in this age group,” but it seemed to me to be pulling together many of the theatrical techniques I’ve seen WEST developing over the past few years with their teen actors. 
They did a lot of chorus work, like at the Shakespeare conservatory; they did a lot with solid colored lights and backlighting (using their LED floods); they had movement pieces like the ones S. Kate Anderson had done for Call of the Wild; there was a “seduction” scene done in single-word lines, inspired by a Carol Burnett sketch that my son and another teen actor had performed at AFE (under WEST direction); and the actors kept changing roles, with a hat or a shawl to mark the characters (also from a Shakespeare conservatory). They had a dance scene under blacklight with fluorescent makeup (WEST has learned something since the days they tried Star Wars with glow-in-the-dark paint—fluorescence is much more visible and controllable than luminescence).
They were pretty true to the plot of the book, while making a very theatrical production, and I was impressed by how well they pulled off a rather difficult bit of theater.  The next generation of WEST actors is going to do well. I was only sad that the light rain had kept people away, and the house was only about 80% full—the performance was good enough that they should have been selling out every night.  (Of course, with only 6 actors, the built-in audience of family and friends is smaller than when they have a larger cast.)

My weekend was busy (in addition to the theater, I did a bit of blogging and spent most of a day putting together a course fee request for two-quarter version of the Applied Electronics course), but my wife was even busier, as she went to a Metropolitan Opera broadcast on Saturday morning, at a different theater chain than the Shakespeare broadcast on Sunday morning.

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