Gas station without pumps

2015 December 22

Small updates to book

Filed under: Circuits course — gasstationwithoutpumps @ 13:56
Tags: , ,

I released a couple more small updates to my book today:

  • revised Chapter 25 (Electrodes) and electrode lab
  • small additions to loudspeaker lab to remove several TODO comments
  • cleaned up many (but not all) overfull-box LaTeX errors

I’ll try to get Chapter 27 (EKGs) and the EKG lab redone by the end of 2015, completing the rewrite that I started in June 2015.  After finishing this pass, I’ll raise the minimum price on the book (probably to $3.99 from $2.99), though the book still won’t be “finished”—I’ll still have 46 TODO comments to resolve.

If anyone is waiting for me to finish the book before buying it, remember that as long as I’m publishing it with leanpub, buying a copy entitles you to all updates for free, so you might as well get it now, before I raise the price.

2015 December 14

Sabbatical leave application 2016

Filed under: Circuits course — gasstationwithoutpumps @ 14:33
Tags: , ,

I’ve got to write an application for sabbatical leave and submit it before 2016 March 11.   My plans are to take sabbatical leave for fall quarters at ⅔ or 5/9 pay for the next five years, to gradually drain the accumulated sabbatical leave credits, rather than spending them all at once getting two quarters off at full pay.  If I do that, I can retire after Winter 2021 with one unused sabbatical credit (which is a little left as you can get, as you have to return to the university for at least as long as the duration of your last sabbatical).

It is better for the department for me to take sabbatical at partial pay, as the savings in salary is returned to the department as Temporary Academic Staffing (TAS) funds, which can be used for hiring lecturers.  If I took salary at full pay, the department would get nothing, and if I took leave without pay, they’d get my full salary—at ⅔ salary they get  the remaining ⅓, which should be enough to hire 1.5 lecturers to replace me for that quarter (and cover the 1.4 courses that I’d not be teaching).

The sabbatical leave form is only for the Fall 2016 leave and asks a lot of questions, some of which are difficult to answer briefly.

The application form shall be accompanied by a statement providing in detail the following information:

a. A brief history of the project, from inception through progress to date and projection as to completion date. This history shall include a description of the applicant’s preparation and any significant contributions already made in the field of activity with which the project is concerned.

I’m planning to do two things in Summer and Fall 2016: work on my textbook and try to find a bioelectronics project to design, preferably in collaboration with a doctor at UCSF.  Unfortunately, I don’t know any one at UCSF who has a problem that would be interesting for me to work on, and I’m not very good at the networking needed to find such collaborators. I’m also more interested in open hardware than in proprietary development, and that could be a bad mismatch for the UC emphasis on making money off of research developments in the biomedical field.

Even if I’m vague in the request about starting a bioelectronics project, giving a brief history of the textbook development will take some thought—I can’t very well give them the 373 blog posts I’ve written about the course, as they probably want only one or two paragraphs.  I suppose I should mention the times I’ve taught the course, the evolution of the lab handouts into the current draft of the book, and the need for revision based on changing the level and pace of the course next year. The course will be moved from upper division (junior/senior) to lower division (freshman/sophomore), and split into two quarters (2 4-unit courses, replacing the current 5+2-unit course).  The move to lower division means reducing the prerequisites (I’ll still have differential calculus as a prereq, but not calculus-based physics), which in turns means beefing up the background in the text and in the class, to cover the physics that the students won’t have had.

The book may be publishable after the Fall 2016 leave, but I’ll probably want to try using it at the slower pace during Winter and Spring 2017, and revise it Summer and Fall 2017, based on that experience.  I’m still not sure when the project will be “completed”.  There are many milestones along the way: used in the course (done Spring 2015), released to the public (done in draft form starting August 2015), all the “to-do” notes in the text done (maybe never—I keep finding more that needs to be improved), adopted for teaching by someone other than me, available on paper (maybe never—the cost of printing is high relative to PDF distribution, but see Textbook should be on paper), available in EPUB and MOBI formats (maybe never—those formats are awful for math and for scientific graphics), freezing an edition and getting an ISBN, distributing through a professional publisher (maybe never—the textbook publishers take way too big a share of too high a price, providing little in return except their name).

b. Significance of the project as a contribution to knowledge, to art, to a particular profession; or as an expected contribution to the applicant’s increased effectiveness as a teacher and scholar.

I could find no intro electronics textbook that was suitable for bioengineering students at the level I wanted to teach.  Everything that had sufficient design content assumed that the students had already had at least a circuits course and often several low-level analog electronics courses. The books that assumed no prior electronics experience all ended up being “cookbooks”, which had students building things that others designed, or “physics” books, doing demos to illustrate concepts, with no design work in either case. There seems to be a real need for books that get students to design simple electronics without years of preliminary drudgery.

c. Name(s) of the location(s) or institution(s) where the project will be carried on, and the names of authorities, if any, with whom it will be conducted.

Textbook writing will happen at home.  Finding a project to collaborate on with someone else is less definite—I’ll probably try to find collaborators at UCSF, though that will not be easy to arrange, as I don’t want to move to San Francisco, but only visit for a few days at a time every couple of weeks. Stanford would be closer, but the doctors at the Stanford medical school have easy access to Stanford engineering faculty, so finding a fruitful collaboration is likely to be harder.

d. Assurances of cooperation, or authorization to conduct the project, received from individuals, institutions, or agencies.

No authorization is needed for the textbook project, and nothing has been set up yet for doing a collaboration.  It may be that I’ll spend much of the first sabbatical just finding people and setting up mechanisms for later collaborations.

e. Description of all financial support expected during the sabbatical leave, including any fellowship, grant, government-sponsored exchange lectureship, or payment for contract research. (See also APM-740-18 and 740-19.)

No external support expected. I may do small amounts of consulting (well less than the 1-day-a-week limit), if the opportunity arises.

f. Description of University service which will be provided if the applicant proposes to substitute significant University service for some or all of the teaching/instructional requirements of a sabbatical leave in residence (See APM 740-8-b & CAPM 900.700-G)

Not doing a leave in residence, but I may still do some service work at UCSC while on leave, like giving the “Speaking Loudly” workshop for Women in Science and Engineering or helping the advising office with new-student orientation.

2015 November 25

Buy Nothing Day

Filed under: Uncategorized — gasstationwithoutpumps @ 20:00
Tags: , , , ,

Today I got a message from Leanpub, the site where I’m selling drafts of my Applied Electronics for Bioengineers book, suggesting that authors provide a discount for Black Friday, the biggest shopping day of the year in the USA (or one of the 10 biggest, depending whose figures you believe).

My family doesn’t engage in the demented frenzy of orgiastic consumerism that the day after Thanksgiving has become in the US.  We, instead, stay home and celebrate Buy Nothing Day.  The celebration is simple: we stay home and buy nothing that day—not venturing out into the crazy traffic of drivers too stoked on the thought of bargains to look out for pedestrians, not doing on-line ordering, not even ordering pizza by phone (though we did do that one year, when we didn’t have enough food in the house for dinner).

Despite our family’s habits, though, I’m going along with Leanpub and offering a discount on my book:  From Friday 2015 Nov 27, through Monday Nov 30 (“Cyber Monday”), I’m lowering the minimum price on my book from $3 to $2.50.  As always, this includes not just the PDF of the current book, but all future updates for as long as I’m publishing the book with Leanpub.

Quite frankly, I doubt that the 50¢ difference (17% OFF!) will result in any more sales. Most of the purchasers of the book are paying more than the minimum anyway (average currently is $4.89, and that includes several people whom I gave free coupons to).

2015 November 23

Meeting for teachers of writing to engineers

Filed under: Circuits course — gasstationwithoutpumps @ 19:00
Tags: , ,

Last Spring I got a small grant from the Academic Senate to create a new “Disciplinary Communications” course for the bioengineering majors (a $7,000 “partial course relief” for 2015–16).  Most of the effort of creating the course happened last year, as we needed to offer the course in Spring 2015, but the money comes for this year.  I’m not actually taking any course relief this year, though my load is lighter than last year, since I’m not doing two overload courses this year.  The money (as all our course relief money) is being spent on hiring a lecturer—paying part of the salary of the lecturer teaching the new writing course.

But I felt that I ought to be doing something this year on improving “disciplinary communications” for bioengineers, in order to have something to report at the end of the year for the grant.  Since the new course was designed last year, the main effort this year will be on tweaking that course and other courses our students do that involve writing.  Rather than work just with the instructor of that new course, I thought it would be useful to gather all the faculty who teach writing to engineering students, to discuss (according to the message I sent out):

  • course design
  • teaching techniques
  • assignments
  • grading techniques
  • use of TAs or graders
  • creation of a “Professional Learning Community” to meet on a regular (quarterly?) basis

There was no set agenda for the meeting—just a chance to meet and talk about what we do. We had a pretty good turnout: 3 ladder-rank faculty, 4 writing instructors, and 1 staff person who teaches writing to a small group of minority students.

After self-introductions we had a wide-ranging conversation about assignments people gave, challenges they faced, approaches to making assignments work better, and so forth.  We did not talk much about TAs and graders, course design, or grading techniques, concentrating more on assignments and teaching techniques.

I’m a lousy note-taker, so I don’t have good notes of what was discussed, but I remember a few things.  I’ll present them here mainly as they apply to me, since that is what I remember best.

None of the ladder-rank faculty are teaching courses where writing is the primary content of the course, but improving student writing is a secondary goal of their courses. In my case, I’m (thankfully) not teaching either the technical writing for bioengineers course nor the senior thesis writing course this year, but I do provide a fair amount of writing feedback both in the Bioinformatics: Models and Algorithms course and in the Applied Electronics course. In the bioinformatics course, there are a couple of writing assignments, but most of the feedback is on in-program documentation. In the Applied Electronics course, there is a weekly design report due, which is centered on the graphics (block diagrams, schematics, and fits of models to measured data). Other courses include assignments to write abstracts, write proposals, write standard operating procedures, and other assignments typical of both academic and industrial writing tasks.

One aspect of teaching writing that I’ve never had much luck with is peer editing—another of the ladder-rank faculty brought this topic up as one of the challenges that help was needed on.  A couple of the writing instructors agreed that peer editing was hard, because the students had no notion of “editing” as an activity. What they suggested was having a set of specific questions for the peer editors to answer—questions relevant to the piece they were editing, like “what is the research question? Is there a summary of results? Is the approach clear?” for editing an abstract.  Without specific guidance, students tend to fall back on the if-you-can’t-say-anything-nice-don’t-say-anything meme, and provide useless “looks good to me” comments.  One technique that the faculty member who raised the issue has tried (with mixed success) is getting students to rewrite another student’s abstract in their own words.  Although this often pointed out problems in the original writing, it sometimes just reflected the inability of the editing student to write coherently.

One idea that seemed to come as a bit of surprise to some of  the writing instructors was creating the figures and figure captions of a document first, and then writing the paper around the figures.  This is a common approach in some research groups in our department, and one that some students will have to face. One of the writing instructors pointed out that the poster assignment (used in two of the courses) is good preparation for this.

We all pretty much agreed that there was no place in the writing instruction students were getting about good presentation of data and generation of figures. I mentioned that one of our junior faculty is interested in creating a course centered on scientific graphics, but it wasn’t clear whether he’d get to teach it next year or not.  I felt that students in my Applied Electronics course got a lot of instruction and got pretty good at displaying data (at least the scatter diagrams and fit models for that course), but that they really struggled with the notion of block diagrams and organizing problems into subproblems. One of the writing instructors, who saw the students mostly after they had had the applied electronics course, saw more problems with data presentation than with block diagrams.  This may be because of different expectations of the block diagram, or it may be that the data representations her students needed were not among the few types covered in Applied Electronics.

Another form of writing that a lot of students were not getting adequate feedback in was lab notebooks. Unfortunately, the different disciplines have such different expectations of the content of a lab notebook that it is hard to provide any sort of standardized assignment. A couple of the instructors who teach Writing 2 classes, mainly to STEM students, do include an observational-field-notebook assignment, which at least gets across the idea of taking notes as you go, and not trying to reconstruct what you did at the end of the day (a flaw I’ve seen in several of the Applied Electronics labs) or the end of the quarter (a flaw I’ve seen in some senior theses).

We did discuss the strategy of setting high expectations on the first assignment by giving detailed feedback on that assignment, with reduced checking on subsequent assignments.  This helps keep the grading down to an almost sane level, and the students still benefit from the practice, even if not everything they do is checked. I’ve certainly noticed on the bioinformatics assignments that by the 4th or 5th assignment I only need to spot-check the internal documentation, or check it for students who are struggling with the concepts of the assignment, as the better students generally are routinely producing decent documentation by then.

We discussed various things we could do that would be generally helpful, and I ended up with two action items:

  • Create a shared Google Drive folder where we can put assignments and examples of student work (access limited to faculty involved in the group).
  • Organize another meeting for next quarter. People were pleased enough by the meeting to want to meet again.

I don’t think that anyone will make any radical changes to how they teach as a result of the meeting, but I think that several of us came away with the nugget of an idea for a small improvement we could make. It was also very refreshing to have a discussion of teaching techniques—something we professors don’t often get a chance to engage in meaningfully.  Most attempts to foster such discussions are way too broad (like the Academic Senate teaching forums) in an attempt to include everyone, or way too bureaucratic (like the attempts of the administration to push assessing “program learning outcomes”).  Today’s informal discussion seemed to me to be focused enough to be productive, yet broad enough to involve many different courses.  I’m looking forward to doing it again next quarter.

2015 November 5

Book draft 2015 Nov 5

Filed under: Circuits course — gasstationwithoutpumps @ 22:39
Tags: , , , , ,

I released an updated version of the Applied Electronics for Bioengineers text today.  This draft involved several changes:

  • Added modifier for “resistor” at end of Section 5.1
  • Changed “load resistor” to “bias resistor” in microphone chapter and lab.
  • Fixed microphone schematics to use polarized microphones.
  • Figure 11.2 changed to use only one differential channel on PteroDAQ.
  • Brief explanation of RMS added to Section 3.2
  • Small fixes to Chapters 9–16 and indexing terms added.
  • Index cleaned up.
  • 60Hz FM figure added to Chapter 14
  • Updated power discussion in Sections 0.5, 12.3, 23.1
  • Updated to include Teensy 3.2
  • Major rewrite of Chapter 23 (Class D power amp)

I’m still not finished with the Class D chapter, but I managed to test today an H-bridge circuit using a 9V power supply, which could provide ±9v signals to a loudspeaker (the full 10W that the loudspeaker can take).  I did not actually drive the loudspeaker that far, but I confirmed that the H-bridge was providing the full voltage range for PWM and that I was getting clean signals at the loudspeaker for loudness I was willing to tolerate listening to.

I’m now convinced that an H-bridge design is a simpler approach to teach the students, as well as being more useful for students who go on into the “assistive technology: motor” concentration.  Modifying the H-bridge to use logic-level signals from the comparator but high voltages for the power FETs turned out to be quite simple.  I just added a small nFET and a couple of resistors to make an inverter with a small voltage swing on the output:

Q1 and the resistors R1 and R2 form an inverter for driving the pFET.  Sizing R1 and R2 determines the voltage swing on the pFET gate  (Q2) and how fast the turn on and turn off are.  Of course, when Q3 is on, there is a current through it that is wasted (not delivered to the load), but I was able to keep that down to about 15mA.

Q1 and the resistors R1 and R2 form an inverter for driving the pFET. Sizing R1 and R2 determines the voltage swing on the pFET gate (Q2) and how fast the turn on and turn off are. Of course, when Q3 is on, there is a current through it that is wasted (not delivered to the load), but I was able to keep that down to about 15mA.

Next Page »

The Rubric Theme. Blog at WordPress.com.

Follow

Get every new post delivered to your Inbox.

Join 335 other followers

%d bloggers like this: