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2016 September 27

Teensy 3.5 & 3.6 Kickstarter

Filed under: Uncategorized — gasstationwithoutpumps @ 16:59
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As many of the followers of my blog know, the Teensy 3.1 and Teensy LC have been my favorite microcontroller boards for the past couple of years.  The Teensy 3.1 has since been replaced by the slightly better Teensy 3.2, which has a better voltage regulator but is otherwise pretty much the same as the 3.1.  I’ve been using the Teensy LC with PteroDAQ software for my electronics course.

I’ve just noticed that PJRC has a Kickstarter campaign for a new set of boards the Teensy 3.5 and 3.6.  These will be much more powerful ARM processors (120MHz and 180MHz Cortex M4 processors with floating-point units, so at least 2.5 times faster than the Teensy 3.2, more if floating-point is used much).  The form factor is similar to before, but the boards are longer, taking up 24 rows of a breadboard, instead of just 14.  The extra board space is mainly to provide more I/O, but there is also a MicroSD card slot.

The designer is still dedicated to making the Teensy boards run in the Arduino environment, and the breadboard-friendly layout is very good for experimenting.

PJRC is positioning the new boards between the old Teensy boards and the Linux-based boards like the Raspberry Pi boards. The new Teensy boards will have a lot of raw power, but not an operating system, though I suspect that people outside PJRC will try porting one of the small real-time operating systems to the board.

The new boards are a bit pricey compared to the Teensy LC ($23–28 instead of under $12 for the Teensy LC), but still reasonable for what they provide.  PJRC also has a history of providing good software for their boards.

I probably need to get both a Teensy 3.5 and a 3.6 to port PteroDAQ to them—that looks like a $50 purchase. If the boards and the software are available in time for me do development on PteroDAQ by December, I might get it done—any later than that and I’ll have no time, as I have a very heavy teaching and service load for Winter quarter.

I suspect that the new Teensyduino software will need a newer version of the Arduino development environment, which in turn would require a newer version of the Mac operating system (my laptop is still running 10.6.8), which in turn probably means a new laptop.

I’m waiting to see if Apple releases a new, usable MacBook Pro in October, so there is a bit of built-in delay in the whole process. I’m not impressed with their recent design choices for iPhones and MacBook Air—I need connections to my laptop—so there is a strong possibility that I may be having to leave the Macintosh family of products after having been a loyal user since 1984 (that’s 32 years now).

Update 2016 Sep 27: I just watched the Kickstarter video.  They used the Karplus-Strong algorithm as a demo.  Of course, that demo could have been done on a Z80 chip from 1976 (though not easily—the sampling rate suffered a bit to run 4 strings on the Z80, and only 8-bit DACs were affordable in those days).  It would have been more instructive to do an FM synthesis algorithm, which takes a lot more processor power than Karplus-Strong.

2016 September 24

US News covers UCSC referendum on athletics

US News and World Report wrote an article,So Long, Banana Slugs? Students Cry Foul About Paying More for Sports, about the UCSC student vote last year on funding athletics.  In it they pointed out that athletics does not really benefit universities:

And while administrators often say athletics benefit their universities—and 77 percent of Americans in a Monmouth University poll said they thought big-time programs make “a lot of money for their respective schools”—the NCAA itself reports that only 24 of its 1,200 member schools take in more than they spend on sports. Even after broadcast rights, ticket sales, sponsorships, sports camp and investment income is taken into account, colleges have to subsidize a median 27.5 percent of athletic spending, much of it from student fees, the AAUP says.

“The fact is, all the data shows that many of the purported academic benefits of sports—recruitment, prestige—have all proven to not be true. They don’t exist,” Tublitz said.

One of the things that I like about UCSC is that sports is a participatory activity, not a spectator activity. A lot more students are involved in intramural sports and in individual fitness activities than bother watching the 250 or so varsity athletes, who the university has been subsidizing at a rate of $1million a year. I’m pleased to see that the national press is noticing that the subsidy of athletics by universities makes no sense, and that UCSC has an opportunity to be a leader in turning their back on this nonsense.

I’ve posted on this topic before: I’m proud of UCSC undergrads, Sports at Any Cost, and Not so proud of UCSC undergrads this year.  I am hopeful that students will realize that subsidizing a couple hundred of their fellow students to play for them is not nearly as valuable as playing themselves—that they are better off taxing themselves for equipment and facilities that all students can use than for special services (coaches, trainers, transportation) for just a few.

I also hope that the UCSC administration comes to its senses and realizes that students are having a hard time getting into the classes they need, because of all the growth in student enrollment without a corresponding growth in instructional resources, and that the $1million dollars a year they pour down the athletic drain  could be used to provide more classes.

That $1million would pay for about 100 more courses taught by lecturers, or 40–50 more taught by tenure-track faculty, about 40 more TA sections.  (Surprisingly, TAs cost departments much more than lecturers, because departments have to pay the tuition for TAs, which get recycled back into other things—like subsidizing athletics, probably.)  The money would benefit about 3000 students a year, rather than the under 300 who benefit from athletics subsidy.

I think that it is past time for UCSC to leave NCAA sports and return to having just club sports, as they did when I first started teaching at UCSC 30 years ago.

 

2016 September 23

Evolution of caffeine

Filed under: Uncategorized — gasstationwithoutpumps @ 13:07
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PZ Myers has a nice discussion of the convergent evolution of the synthesis of caffeine (separately evolved at least 5 times!), based on the paper from PNAS, Convergent evolution of caffeine in plants by co-option of exapted ancestral enzymes, by Huang, O’Donnell, Barboline, and Barkman.

Biologists used to think that there was one canonical pathway for caffeine synthesis, from xanthosine through 7-methylxanthine and theobromine to caffeine.  The paper shows that some plants use a different pathway (through 3-methylxanthine and theophylline) and that the enzymes used even on the common pathways are different.

The evolutionary model that best explains the data is that ancestral enzymes were promiscuous (which means that they had several different functions, not that they were sexual) and were eventually duplicated and specialized for caffeine production.  The researchers reconstructed some of the ancestral enzymes from the modern descendants and confirmed that this hypothesis was reasonable, as only single amino-acid substitutions were necessary to confer the two different specificities of the modern enzymes from the ancestral ones.

Threadsteading: A Game for Quilting and Embroidery Machines

Filed under: Uncategorized — gasstationwithoutpumps @ 11:03
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I just found out about a cool game, but one that few people can play: Threadsteading.

Threadsteading is a two-player game for a modified quilting machine. The quilting machine is a computer-controlled longarm quilting machine, which moves a sewing head around a 12′ x 2.5′ area to stitch 2D paths.

Threadsteading-Image1Our custom input controller is attached to the sewing head, so it is always located just under the fabric surrounding the needle’s position. We’ve also reverse-engineered the control to the machine so we can send sewing paths directly to it. The game is thus played entirely on the quilting machine, and each round of the game results in a permanent physical artifact: a quilt.

full article at  Disney Research » Threadsteading: A Two-Player, Single-Line, Territory Control Game for Quilting and Embroidery Machines

They also have a version of the game that can be played on a smaller scale on a computer-controlled embroidery machine, which is something that is more likely to be found in a home.

I found out about the game because two of the designers are affiliated with UCSC (April Grow is a grad student who was a Disney Research intern, and Gillian Smith is a UCSC alumna), so the game was mentioned in a recent press release by Tim Stephens about student-designed games in the UCSC game-design program: UC Santa Cruz student games featured at IndieCade Festival.

Some of the other games mentioned in that press release also sound interesting, but none are quite as out-of-the-norm as a game on a quilting machine.

2016 September 20

Trick for encouraging cooperation

Filed under: Uncategorized — gasstationwithoutpumps @ 15:26
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Adam Grant, a professor at the Wharton School of the University of Pennsylvania, provided an interesting technique for encouraging cooperation in his business-school classes (a culture noted for cut-throat competition between students):

How could I get students to help one another?

Four years ago, I found a way. The most difficult section of my final exam was multiple choice. I told the students that they could pick the one question about which they were most unsure, and write down the name of a classmate who might know the answer — the equivalent of a lifeline on the game show “Who Wants to Be a Millionaire?” If the classmate got it right, they would both earn the points.

Essentially, I was trying to build a collaborative culture with a reward system where one person’s success benefited someone else. It was a small offering — two points on a 120-point exam — but it made a big difference. More students started studying together in small groups, then the groups started pooling their knowledge.

You can read more about his attempts to encourage student cooperation in Why We Should Stop Grading Students on a Curve, published in the New York Times.

I don’t think I can use this exact technique, as none of the courses I teach involve exams—all are graded on the written reports that students write.  I could use it for homework, I suppose, but the overhead of checking other student’s responses might increase the turnaround time for homework grading.  I’m also already seeing more cooperation on the homework than I really want.

Furthermore, students quickly learn who the best student in the class is, and would just point to him or her, with no increase in useful cooperation.  So I think this technique would only work in student cultures that currently have a high degree of secretiveness and competition, not in already collaborative cultures.

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