Shallow Thoughts : : Sep
Akkana's Musings on Open Source Computing and Technology, Science, and Nature.
Tue, 18 Sep 2007
It's nearly autumn, and that's the time of year when a girl's heart
turns to ...
BIG FAT HAIRY SPIDERS!
That's right, the tarantulas are on the move.
Mostly, tarantulas are hard to see. They stay in their underground
burrows for most of their lives; if they do come out of the burrow,
it's likely to be at night.
But for a few weeks each fall, male tarantulas become more
adventurous, when they emerge from their burrows and wander in search
of females. The females stay snug underground,
but the males can often be spotted on roads and trails, if you
know where and when to look.
Ah, but where and when?
I've seen tarantulas numerous times at Alum Rock Park (in San Jose)
and at Arastradero (in Palo Alto) ... but not in the last four years.
In recent years, Dave and I have gone out every October looking for
spiders, and have struck out locally. (Fortunately we've had better
luck on trips, so not all of these years were completely
tarantuless -- we've found them in places like Arizona's
Valley of the Gods
and Utah's Kolob Canyon.)
This year, we got started early, in September.
We had no luck at Alum Rock last weekend,
so this evening we took a late-afternoon hike a little higher
up in the east bay hills, at Grant Ranch.
On the trail by Grant Lake, we got rattled at by a fairly large western
rattlesnake, saw an underground beehive as well as lots of small
wasps, watched a flock of wild turkeys down by the parking lot,
and found a lovely feather from the blue heron at the lake.
But ... no spiders.
So we got back in the car and continued up Mt Hamilton Rd toward
the upper parking lot (Twin Gates). About two-thirds of the way there,
Dave spotted our quarry: a tarantula crossing the road. We found a
pullout and ran back with cameras.
After the photo session, we continued up the road to Twin
Gates for another mini-hike. Again, we saw no tarantulas on the
trail -- just hawks and kites, an oak tree covered with acorn
woodpecker holes (with the woodpeckers themselves darting among the
branches), and another oak tree being killed by mistletoe.
We returned to the car and headed back down the road -- and bagged
the day's second spider, scurrying across one of the roadside
pullouts. A nice end to the day's spider hunt!
Photos of the two tarantulas are here.
[ 23:16 Sep 18, 2007
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Fri, 14 Sep 2007
The new semester started last week. I'm taking a class
that's held in a new building:
When Dave first saw the building, he laughed. "No wonder they're
complaining that fewer students are taking science and math classes --
they're sending the wrong message! They ought to call it 'Science
Simple'. Then they'd get lots of students signing up."
[ 22:12 Sep 14, 2007
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Sat, 08 Sep 2007
It's always amazed me that Linux doesn't let you customize the system
beep. You can call
xset b volume pitch duration
make it beep higher or lower, or you can turn it off or switch
to "visual bell"; but there's nothing like the way most other OSes
let you customize it to any sound you want. (Some desktops let you
customize the desktop alerts, but that doesn't do anything about the
beeping you get from vim, or emacs, or bash, or a hundred other
programs that run in terminals.)
Today someone pointed me toward a
wiki page that led me to
Daemon. This is a small kernel module that adds a device,
/dev/beep, which outputs a byte every time there's a beep.
You can write a very simple daemon (several samples in Python are
included with the module) which reads /dev/beep and plays the
sound of your choice.
I downloaded beep-2.6.15+.tar.gz, but it needed one tweak
to build it under 2.6.23-rc3: I needed to add
among the includes at the beginning of beep.c.
After that, it compiled and installed just fine.
Since it's a kernel module, it works in consoles as well as under X.
/dev/beep is created with owner and group root, and readable/
writable only by owner and group, so to test it I had to
chmod 666 /dev/beep to run the daemon. I fixed that by
making a file in /etc/udev/rules.d called 41-beep.rules,
Finally, based on the nice samples that came with the module, I wrote
my own very simple Python daemon,
that uses aplay.
Lots of fun! I don't know how much I'll use it, but it's good to have
the option of custom beep sounds.
[ 21:47 Sep 08, 2007
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Tue, 04 Sep 2007
I left the water on too long in the garden again.
I keep doing
that: I'll set up something where I need to check back in five minutes or
fifteen minutes, then I get involved in what I'm doing and 45 minutes
later, the cornbread is burnt or the garden is flooded.
When I was growing up, my mom had a little mechanical egg timer.
You twist the dial to 5 minutes or whatever, and it goes
tick-tick-tick and then DING! I could probably
find one of those to buy (they're probably all digital now
and include clocks and USB plugs and bluetooth ports) but since the
problem is always that I'm getting distracted by something on the
computer, why not run an app there?
Of course, you can do this with shell commands. The simple solution
(sleep 300; zenity --info --text="Turn off the water!") &
But the zenity dialogs are small -- what if I don't notice it? --
and besides, I have to multiply by 60 to turn a minute delay into
sleep seconds. I'm lazy -- I want the computer to do that for me!
Update: Ed Davies points out that "sleep 5m" also works.
A slightly more elaborate solution is at. Say something like:
at now + 15 minutes
and when it prompts for commands, type something like:
zenity --info --text="Your cornbread is ready"
to pop up a window with a message.
But that's too much typing and has the same problem of the small
easily-ignored dialogs. I'd really rather have a great big red
window that I can't possibly miss.
Surely, I thought, someone has already written a nice egg-timer
application! I tried aptitude search timer and found several
apps such as gtimer, which is much more complicated than I wanted (you
can define named events and choose from a list of ... never mind, I
stopped reading there). I tried googling, but didn't have much luck
there either (lots of Windows and web apps, no Linux apps or
Clearly just writing the damn thing was going to be easier than
(Why is it that every time I want to do something simple on a computer,
I have to write it? I feel so sorry for people who don't program.)
I wanted to do it in python, but what to use for the window that pops up?
I've used python-gtk in the past, but I've been meaning to check out
TkInter (the gui toolkit that's kinda-sorta part of Python) and
this seemed like a nice opportunity since the goal was so simple.
The resulting script:
Call it like this:
eggtimer 5 Turn off the water
and in five minutes, it will pop up a huge red window the size of the
screen with your message in big letters. (Click it or hit a key to
First Impressions of TkInter
It was good to have an excuse to try TkInter and compare it with python-gtk.
TkInter has been recommended as something normally installed
with Python, so the user doesn't have to install anything extra.
This is apparently true on Windows (and maybe on Mac), but on
Ubuntu it goes the other way: I already had pygtk, because GIMP
uses it, but to use TkInter I had to install python-tk.
For developing I found TkInter irritating. Most
of the irritation concerned the poor documentation:
there are several tutorials demonstrating very basic uses, but
not much detailed documentation for answering questions like "What
class is the root Tk() window and what methods does it have?"
(The best I found -- which never showed up in google, but was
referenced from O'Reilly's Programming Python -- was
In contrast, python-gtk is
very well documented.
Things I couldn't do (or, at least, couldn't figure out how to do, and
googling found only postings from other people wanting to do the same thing):
- Button didn't respond to any of the obvious keys, like Return or
Space, and in fact setting key handlers on the button didn't work --
I ended up setting a key handler on the root window.
- I couldn't find a way to set the root window size and background
explicitly, so I had to set approximate window size by guessing at
the size of the internal padding of the button.
- There's an alternate to the root Tk() window called
Toplevel, which is documented and does allow setting window
size. Unfortunately, it also pops up an empty dialog without being
told to (presumably a bug).
- All of the tutorials I found for creating dialogs was wrong,
and I finally gave up on dialogs and just used a regular window.
- I couldn't fork and return control to the shell, because TkInter
windows don't work when called from a child process (for reasons no
one seems to be able to explain), so you have to run it in the
background with & if you want your shell prompt back.
I expect I'll be sticking with pygtk for future projects.
It's just too hard figuring things out with no documentation.
But it was fun having an excuse to try something new.
[ 14:35 Sep 04, 2007
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