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2020 August 17

PteroDAQ installation video

Filed under: Circuits course — gasstationwithoutpumps @ 21:52
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As part of my lecture videos for the first half of the electronics course, I’ve created a video on installing PteroDAQ:

and put in the playlist Applied Analog Electronics Part A.  The instructions are only for macos, but similar steps are needed on Linux and Windows machines.

2020 August 9

Videos for Fall done!

Filed under: Circuits course — gasstationwithoutpumps @ 09:35
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I think that I finished the videos for BME 51B last night—53 days before classes start.  There are 49 videos totalling 11 hours and 49 minutes (averaging 14 minutes, 28 seconds).

So far, only one of them has had the captions edited (, but the student doing the caption editing is beginning to get the hang of it and I expect the caption editing for subsequent videos to be done more rapidly.  The process is somewhat simpler than I expected, as we don’t need to do anything with time stamps.

  1.  Download the auto-generated transcript of the video using, which can provide the transcript in a simple text format without time stamps.  For some reason, YouTube does not provide an easy way to get this with their native interface—only providing a file in VTT format, which has lots of duplication of words in order to simulate scrolling.  The VTT format is much richer than the simple text format, but very hard to edit to correct bad line breaks and incorrect punctuation.  (I saved the VTT files, in case I need to restore the autocaptioning, but I don’t expect to use them.)There is a way to get the transcript on the native YouTube interface, but it involves screen-scraping and doing a cut-and-paste to a new file.  The download just needs the YouTube URL and keeps the title of the video as part of the file name, making a much more usable interface.
  2. Edit the text file, keeping all lines to 45 characters or fewer.  The point of the editing is to correct mistranscribed words (there were two or three in a 20-minute video, and for one of them even the student couldn’t figure out from my mumbling), to eliminate verbal glitches, to correct punctuation, and to put the line breaks at semantically meaningful places (where possible) to make reading the captions easier. Music at the beginning and end should be labeled as “[Music]”.
  3. Upload the edited transcript, as described in and  One step seems to be missing there—the upload silently failed the first time I did it, with YouTube still showing the auto-generated captions the next day.  I tried again, deleting the autocaptions when uploading the edited transcript file, and that seems to have worked.

The student hired by the university does steps 1 and 2.  I do one more editing pass over the transcript, correcting any places where the student was unsure of the transcription and looking for punctuation errors (mainly comma splices and hyphenation errors).  The comma splices are a natural result of spoken speech not being obviously broken into sentences—run-on sentences are a common speech pattern.  Judicious punctuation makes the captions easier to read correctly without changing the words of the utterances.  On the first video, I fixed half a dozen punctuation and capitalization errors, corrected one word that the student was unsure of, and corrected another phrase that YouTube had mistranscribed and the student had not caught.  It took me much less time and pain to do that final editing pass than it would have to do all the editing, so it was definitely worthwhile having the student do the initial editing.

I have not yet estimated how many videos I’ll need for BME 51A for the Winter, but I think that there will be closer to 20 hours of video than the 12 hours for BME 51B, so I don’t think I’m halfway yet through the whole course. I’ll probably not quite have finished them by October 1, when Fall classes start, but I might be able to get them done before the grading load for BME 51B crushes me.

I’ll also need to do some videos that won’t go up publicly on YouTube: 10 quiz solutions each for BME 51A and BME 51B.  I’ll probably also do an intro video for each course, calling student attention to important parts of the syllabus—the intro videos may go up on YouTube, but not be part of the playlist.

I’m probably going to rename the Applied Analog Electronics playlist to Applied Analog Electronics Part B, and create a new playlist Applied Analog Electronics Part A.  That will make it easier for students to find the videos they need, and it will make it easier for me keep the videos in order—it is much easier to add a new video at the end of a playlist than to add it somewhere near the beginning.

2020 July 23

Fall 2020 plans and tools

Filed under: Circuits course — gasstationwithoutpumps @ 13:44
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I swapped my Fall sabbatical for a Spring one, so that I could have time to figure out how to move my lab course into an at-home lab. I also took a university-sponsored course this summer on remote instruction to help.  That course on remote-instruction has now ended, but I still have some work to do on converting my course.  USCS will still be providing some help—they’ll be paying for a student (one of my graders from last Winter) to edit the closed captions on my videos.

I’ve made a list of some of the tools I’ll be using for the Fall:

  • I’ll be using Canvas for collecting assignments (as I have for a couple of years) and SpeedGrader or Gradescope for grading them (the badly-named SpeedGrader for written assignments, as I’ve been doing, and Gradescope for quizzes, which will no longer be on paper).
  • I have my syllabus on my own website on the University server, so that it is public (I hate secret syllabi buried inside a learning-management system—they make it nearly impossible for students to know what a course is about before they have committed to taking it). All assignments, reading schedules, … are there. Only the assignment due dates are duplicated in Canvas.
  • I use Piazza for having students ask questions, as I’ve been doing for a couple of years. It is a much better interface than the Canvas discussion forums, and students are willing to use it.
  • I’ll be using Zoom for the synchronous parts of the course—lab times and office hours. That is new for me, but I’ve been in enough Zoom meetings, classes, and webinars now to have some idea what is reasonable. I’ll undoubtedly find all sorts of new problems in the first 2 weeks of class (particularly with breakout rooms, which have not worked very well any time I’ve been in them).
  • The small stipend I got for converting my course to online required that the lectures be fully asynchronous (and that any synchronous activities be attendable even by people in a time zone 15 hours different from mine). So I’m recording mini-lectures (6 minutes to half an hour) using OBS. I’ll probably have about 35–40 of them (considerably less lecture time than the usual 32.5 hours of lecture for the course, but some of that time would normally be taken up with quizzes). I’ve set up my desktop computer at home (shared with my wife) as a recording studio, with a green screen, a document camera, and (starting today, if it arrives as scheduled) a cardioid desktop microphone.
  • I’m also planning to have video answers to the quizzes that are unlocked by submitting the quiz—those I’ll have to do at the last minute, as I usually write each quiz after seeing what students got wrong on the previous quiz. The quizzes are fairly low stakes (all 10 quizzes add up to about 13% of the grade), so I’m not going to worry that a few of the students are going to cheat like hell on them—I’ll be saddened by the cheating, but I’m not going to proctor. If I get obvious cheating (like identical very wrong answers that can’t be easily explained except by copying), I’ll still do the academic-integrity reporting and fail the students.

I’ve recorded 31 mini-lectures so far, and I’m gradually getting better at using OBS and lecturing into the void, but it is very, very different from my usual style, which involves 50′ chalkboards and is an improvisational performance in response to student questions. I’m glad that I only have to do this online stuff for one year (I’m retiring in 2021).

UCSC is  almost fully online this Fall (21 in-person courses out of 1300, mostly small lab or grad courses, so less than 0.5% of total seats).  I expect that Winter quarter will be much the same, though some optimists expect more in-person course (up to maybe 5% of total seats).

I still have to work out (with the Baskin Engineering Lab Support staff) the logistics of shipping stuff to the students. The parts that were ordered for the cancelled Spring course are available in storage at UCSC, but we’ll have to add to the list to provide some duplication for mistakes (as students can’t get same-day replacements from the BELS supply room, nor can they borrow easily from classmates), plus providing resources that were previously communal (inductors, wire, solder, soldering irons, solder suckers, safety goggles, stainless-steel electrodes, electrode holders for Ag/AgCl electrodes, …).  I’ll be making up a list soon of the changed needs for the parts kits.  We’ll also have to work out which things the students need to ship back over winter break, for distribution to BME 51A students in Winter.

We’ll probably freeze the enrollment in the class in mid-September (no late adds this year!), so that there is time for shipping.  I currently have only 32 students in the class, down considerably from the 50 who passed the first half in Winter 2020.  Some students graduated in Spring 2020 (we granted some emergency course substitutions for students whose required courses were cancelled in Spring), but I was still expecting about 40 students this Fall.

2020 July 13

Twenty-one videos for electronics book

Filed under: Circuits course — gasstationwithoutpumps @ 22:26

I’ve just published my twenty-first video for my Applied Analog Electronics book. I stopped announcing each one on the blog (the posts were getting repetitive).  You can see the entire set (in viewing order) in the Applied Analog Electronics playlist. If you want to be informed when new videos are added, subscribe to the playlist on YouTube.

I now have most of Chapters 27–32 done. I’ve got about 85 more days until classes start, so I’m pretty sure I’ll have all the BME 51B videos done, but I’m not so sure I’ll get all the BME 51A videos done.  I do have until the beginning of January for those.

I’m getting a little better about the production values: the green screen is better, I have intro music that I composed, I switch between “scenes” a bit better, and I’m a little more comfortable talking to the screen without an audience.


2020 July 10

Ring light for iMac

Filed under: Circuits course — gasstationwithoutpumps @ 08:19
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I was having some trouble using the green-screen capabilities of OBS, and the videographer who works on online courses for UCSC suggested trying a ring light behind my iMac to get more light on my face. I decided to make a ring light and see if it helped.

On Wednesday I walked to my dentist appointment, rather than bicycling, so that I could stop by Palace Arts on the way home to pick up a piece of foam core to make a frame to tape to the back of the iMac, without blocking any ventilation ports.  I already had strips of LEDs that I could use to provide the light.

Here is the layout of the ring light, seen from the front, before mounting it on the iMac.

The hinge (made by scoring the foam core and then crushing the foam slightly at the score line) allows the monitor angle to still be adjusted, even with the foam core taped to both the stand and the back of the computer.

Here is the ring light attached to the back of the iMac with blue painter’s tape and lit up.

The ring light was not difficult to make, but it did not do what we had hoped. It does illuminate my face a bit more uniformly, but the camera in the iMac automatically compensates for the extra light, resulting in the green-screen background looking olive drab and being even harder for OBS to use in chroma keying. It’s too bad that OBS doesn’t have Zoom-like background elimination, which can handle a much wider variation in color and lighting of a green screen. The ring light also does not work well with glasses, as there are two really annoying reflections of the light off the front and back surfaces of my glasses.

So I wasted a day experimenting with the ring light. My next attempt at improving the green screen will be to mount a strip of LEDs at the bottom of the cloth screen, to see if I can erase some of the shadows there and get more uniform and brighter lighting of the screen.

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