Gas station without pumps

2016 May 16

DASL Updated

Filed under: Uncategorized — gasstationwithoutpumps @ 08:25
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Tim Erickson, a statistics teacher, announced in his blog, A Best-Case Scenario DASL Updated. Mostly improved.

The Data and Story Library, originally hosted at Carnegie-Mellon, was a great resource for data for many years. But it was unsupported, and was getting a bit long in the tooth. The good people at Data Desk have refurbished it and made it available again.

Here is the link. If you teach stats, make a bookmark:

It looks like there are a number of good small data sets there, suitable for toy problems in statistics classes.

2016 May 12

Sprockets closed again

Filed under: Uncategorized — gasstationwithoutpumps @ 21:43
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I reported in 2012 that one of my favorite bike shops (Sprockets on Mission Street in Santa Cruz) had closed without any fanfare, and a couple of months later that they had reopened under new ownership.

Unfortunately, they seem to have gone out of business again—my wife went there on Monday to get a new floor pump for the soda-bottle rockets, and they weren’t there. I don’t know the reason, but I suspect that they were not moving enough product to make their payroll—bike shops are a tough business, and there are two others within 0.7 miles on Mission Street, as well as one downtown (about a mile away).  That doesn’t count the two (or is it three) on the Eastside, just a mile further away, nor the one near the beach, about a mile away.

The City of Santa Cruz can support 7 or 8 bike shops, but only marginally—it is more a labor of love than a profitable business enterprise.  (Note: one bike shop per 7,000–8,000 residents is a high concentration for the US. There were supposedly only 3790 specialty bike shops in the USA in 2015 [], which is a ratio of one shop per 84,000 people. So Santa Cruz is still doing at least 10 times better than the US as a whole.

It will be annoying to have to walk 0.6 miles instead of 0.4 miles to the nearest bike shop, but not a major hardship. I just hope that the circumstances are not as dire as the previous closure of Sprockets (one of the co-owners died and the other decided not to continue the shop without her).

Soda bottle rockets used again

Filed under: Uncategorized — gasstationwithoutpumps @ 20:48
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I had another chance on Tuesday this week to play with soda-bottle water rockets, which I have not done since my son was taking home-school physics and we wrote the timing program for measuring the ascent of the rockets that later turned into PteroDAQ to go along with the homemade Lego “superpulley”.

My wife volunteered me to help out at the Spring Hill School’s Family Science Night—a tradition I started 9 years ago (here are my notes from the 2 years I ran it).  She had thought I could set up the “Dr. K’s Applied Electronics” display I’d used at the Mini Maker Faire, but I didn’t have the time it would take to set up the display (over an hour, to do it right).  Instead, we agreed to revive the soda-bottle water rockets, which are always a hit with elementary-school kids.

I raced home from running the pulse-monitor lab for the Applied Electronics course, loaded up my bike trailer with empty mineral water and soda bottles, a couple of floor pumps, and some rocket launchers.  My wife also brought a few copies of the instructions for making the PVC launchers, though not the Spanish-language version, which we first created in 2001, when my son was in kindergarten (a post I wrote in 2011 talked a bit about the activities I did with the Kindergarten kids to explain how rockets worked).

The rockets were a big hit at Family Science Night last night, though the kids preferred the commercial launcher that I believe I bought from Arbor Scientific (which can be seen in the superpulley post and the water-rocket simulation posts 1 and 2).  Nonetheless, several families did take instructions for making the simple PVC launchers, with the intent of doing it as a fun project this summer.

It was fun to do the science outreach, though I only managed to talk with one family about how rockets worked, and it gave me a good excuse for not doing any grading that night (after 3 days of doing not much besides grading, teaching, and supervising the students in lab, a night supervising kids sending up soda-bottle water rockets was a welcome relief).

2016 May 5

PCB CAD tools

Filed under: Uncategorized — gasstationwithoutpumps @ 20:58
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I’ve been using Eagle for designing printed circuit boards for a few years now, and I am reasonably happy with it as a free tool. However, I’m a little annoyed by the low quality of the schematics and by the awkward creation of new footprints for components, and so I am willing to consider other tools, and am looking for recommendations for free PCB tools that are better than Eagle.

Two I’ve heard of (but not tried yet) are

  • EasyEDA , which is web-based, and
  • DipTrace, which (like Eagle) is a commercial package with a free, but limited, hobbyist version.

I’ve not used either of these yet, and I don’t have any PCB designs to do right now (nor time to do them until the quarter ends), but I’m curious whether any of my readers have tried EasyEDA or DipTrace, particularly if they can compare them with Eagle.  I’m also curious whether there are other PCB tools out there that run under both Mac OS X and Linux and that are free, easy to use, and robust.

My son and I are planning a couple of boards this summer as part of the LED theater lights project, so there will be an opportunity then to try out different PCB tools, if anyone has ones to recommend.

Democratic primary very important this year

Filed under: Uncategorized — gasstationwithoutpumps @ 20:48
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The Democratic primary is very important this year, because it gives US voters the opportunity to choose between a New Deal Democrat (Sanders) and an Eisenhower Republican (Clinton).  This is the first time since George McGovern ran in 1972 that such a choice has been offered to the US people.

The Republican party itself no longer offers serious candidates for president (and increasingly often doesn’t for other races either), so the Democratic party has taken over most of the Republican policies and positions and offers Republican candidates a place to run for office without having to associate with the clowns who have made the GOP into a circus sideshow.

Personally, I’m a progressive Democrat, so I strongly favor Sanders’s policies, but I can see a lot of Republicans voting for Clinton, whose stand on almost every issue is a late 1950s Republican position (except that Eisenhower warned us about the military-industrial complex, while Clinton supports it whole-heartedly).

Because the Republican Party is incapable this year of running a serious Presidential candidate, the Democratic primary is doubly important—it is the only chance voters will get to choose between a classic Democrat and a classic Republican.


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