Pretzels

Today I was out with the kids, and we came across a place selling fresh-baked pretzels. "Mmm, those smell GOOD," said Eli. "Want to try making some when we get home?" I asked. "Sure!" he said, sounding surprised that such a thing was even possible. One quick check of "More Food that Really Schmecks" later, and we were off to the races.

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Tags: geekdad

LISA 2016 - Day 0/1/2

LISA again! This is the fifth? (Washington, Baltimore, San Diego, San Jose, Seattle, and now Boston) sixth! that I've been to. Saturday's flight in was fairly uneventful, except a) it didn't bother my sciatica too much, so yey and b) I forgot my coat on the plane, and it doesn't look like Air Canada has a working system to take "Hey, did you see a coat?" calls.

Fortunately I can count on the kindness of Andy Seely, who brought an extra coat and loaned it to me. For his kindness I have given him a "Taggart Transcontinental" t-shirt, and let him buy me supper. I'm nothing if not generous.

Sunday I spent the entire day at the Google SRE tutorial, which was very, very cool; a big part of it was an exercise to architect a system that would read and join logfiles. It took a long time to wrap my head around how everyone was thinking about this, but writing down the moving parts made it all a lot clearer. In the end, my team's proposal approximated the final example config presented by Google, so that was good. Final sol'n, BTW, used 101 machines. The math all worked out, but it still made my jaw drop. When I asked the presenters about this, they grinned. "We've forgotten how to count small," one of them said.

Today was spent in "Everything you ever wanted to know about operating systems but were afraid to ask", aka "Caskey's Brain Dump". It was a pretty awesome talk, covering everything from silicon through filesystems. Well worth it; I'd love a recording of it, since the slides simply don't do it justice.

Tags: lisa

That's it.

Docker refuses to start. My IPv6 tunnel has started working again after it refused to do so. I have had it with home system administration. I have better things to do with my time.

Tags:

Out of the pen of Glenn Beck

Holy crap, Glenn Beck is a reasonable man:

If you voted for Hillary Clinton this week, you likely feel despondent, confused and unable to reconcile how the country elected Donald J. Trump. “Don’t people see how dangerous this man is?” Clinton supporters asked. “Our entire way of life is at stake.”

I get it. I opposed Mr. Trump, too. But this is how nearly half the country felt eight years ago. It does not matter if we do not understand one another’s feelings. What matters is that we at least hear them.

How do we stop the cycle?

Tuesday night, as it became apparent that Mr. Trump would win, I saw myself as others may see me. Pundits were beside themselves talking about sexism, “whitelash” and bigotry. I read three articles comparing him to Hitler. I understand what they meant. But just as President Obama was not a Manchurian candidate, Mr. Trump is not Hitler. The seeds of 1933 may have been planted, but they can grow only through our hate and divisiveness.

I don’t question your right and reasons to feel fear. But don’t fear Donald Trump the way I feared Barack Obama. I read a perfect election summation: The people who were against Mr. Trump took him literally but not seriously. His supporters took him seriously but not literally. It is the same pattern of 2000 and 2008. We heard President Obama was coming for our church and our guns. We were mocked. We thought those who laughed were lying or stupid. Yet, I still go to church, sometimes with a gun.

Tags: politics

Moving on

Well, that happened. Tuesday night I went to bed hoping for better news. I woke up at 2.30am, unable to sleep; after a while I gave up and came down. Still no good news. President Trump it is, help us all.

But. This morning there was an ISS flyover, and a rare semi-clear sky to see it. So I fired up the ISS HDD viewer on my laptop, went outside, and watched the sun rise from the ISS while I watched it fly overhead, a wonder heading for the dawn.

Tags: politics space

CAN I ROCK BUSINESS WITH YOU?

Today's title from the subject line of some spam I just got. ("a spam"? "a spammy email"? just "spam"?)

  • Mystery flu-like illness continues, or at least its fallout; I've had lower back pain for the last ~ 4 weeks. Doctor says removing spine is "not an option" but I've done some Googling and

  • $WORK continues apace. After taking a week of Python training, we're using Go for a new tool we're building. Haven't got a good sense for what it's like just yet, but so far I don't seem to be making a mess of things.

  • Tried out drone.io at $WORK yesterday and holy god, is it good. Auth with our internal Github, then activate repos, and boom! it runs tests on every new commit on any branch, watches for PRs, the whole nine yards. When I think of the amount of work we had to do to get Jenkins to do this, it's insane. Plus the whole run-as-a-Docker-container, fire-up-sibling-docker-containers-for-tests thing is very, very impressive.

  • Sportsball has started up again with a vengeance: practices on Monday and Wednesday, games on Fridays and Saturdays. Somebody stop this merry-go-round!

  • I've registered for LISA 16, woot! This will be my fifth -- wait, sixth? -- LISA, ten years after my first time attending. Not sure who's gonna be the theme band this year -- I've done New Pornographers, Josh Rouse, Soul Coughing and Sloan. And since he's co-chair this year, it seems like a good time to pull out that picture of Matt Simmons (@standaloneSA) as a PHP dev:

Matt as drugged-out PHP developer

Tags: spam geekdad lisa python golang drone

I'm done

I have spent this weekend debugging shit on my home server: I've managed to break my IPv6 tunnel and Docker networking, and for some reason /etc/resolv.conf was emptied I don't even know why. Last weekend I spent far too much time debugging problems with DKIM and SPF and breaking my wife's email, and that was with only one domain; I've still got another to go through. I am thoroughly sick and tired of it.

I have always thought it important to run your own server (buy me a beer some time to get the reasons), but I am done. Done, I say. I am ready, at this point, to throw money at someone or something to just make this go away. I still want my own SSH server at home -- that's too much to give up -- and I still like checking my mail with Mutt. But web hosting, docker networking, metrics, monitoring, DNS, backups, calendaring -- gahhhhhhhhhhhhhh.

Probably, I am just going to put all this away for now, leave the unpaid sysadmin work for another time.

Tags: wellnotreally

Today's bit of weirdness

The recent Lawfare Podcast episode "Disrupting ISIS Recruitment Online" makes fascinating listening. It's a recording of a panel discussion consisting of two Google-affiliated companies that do targeted advertising aimed at, well, disrupting ISIS online recruitment, and the US Undersecretary of State for Public Diplomacy and Public Affairs.

It is, at first listen, profoundly weird to hear the jargon of online advertising applied to propaganda. (It's propaganda I agree with, but propaganda nonetheless.) But then I realized where I'd come across the idea before: Robert A. Heinlein's "If This Goes On --". Here's a quote:

'I'm in the Psych & Propaganda Bureau,' he told me, 'under Colonel Novak. Just now I'm writing a series of oh-so-respectful articles about the private life of the Prophet and his acolytes and attending priests, how many servants they have, how much it costs to run the Palace, all about the fancy ceremonies and rituals, and such junk. All of it perfectly true, of course, and told with unctuous approval. But I lay it on a shade too thick. The emphasis is on the jewels and the solid gold trappings and how much it all costs, and keep telling the yokels what a privilege it is for them to be permitted to pay for such frippery and how flattered they should feel that God's representative on earth lets them take care of him.'

'I guess I don't get it,' I said, frowning. 'People like that circusy stuff. Look at the way the tourists to New Jerusalem scramble for tickets to a Temple ceremony.'

'Sure, sure-but we don't peddle this stuff to people on a holiday to New Jerusalem; we syndicate it to little local papers in poor farming communities in the Mississippi Valley, and in the Deep South, and in the back country of New England. That is to say, we spread it among some of the poorest and most puritanical elements of the population, people who are emotionally convinced that poverty and virtue are the same thing. It grates on their nerves; in time it should soften them up and make doubters of them.'

'Do you seriously expect to start a rebellion with picayune stuff like that?'

'It's not picayune stuff, because it acts directly on their emotions, below the logical level. You can sway a thousand men by appealing to their prejudices quicker than you can convince one man by logic.. You can sway a thousand men by appealing to their prejudices quicker than you can convince one man by logic. It doesn't have to be a prejudice about an important matter either. Johnnie, you savvy how to use connotation indices, don't you?'

'Well, yes and no. I know what they are; they are supposed to measure the emotional effects of words.'

'That's true, as far as it goes. But the index of a word isn't fixed like the twelve inches in a foot; it is a complex variable function depending on context, age and sex and occupation of the listener, the locale and a dozen other things. An index is a particular solution of the variable that tells you whether a particular word is used in a particular fashion to a particular reader or type of reader will affect that person favorably, unfavorably, or simply leave him cold. Given proper measurements of the group addressed it can be as mathematically exact as any branch of engineering. We never have all the data we need so it remains an art-but a very precise art, especially as we employ "feedback" through field sampling. Each article I do is a little more annoying than the last-and the reader never knows why.'

I'll leave my ambivalence about Lawfare for another day. For now: the podcast makes fascinating listening, and if you haven't read "If This Goes On--", I highly recommend it.

Tags: politics

Updates, Sep 2016

  • This week I've been taking Python3 training at work: 4 days of staying at home and concentrating on Python. The result? 4 days to work on Python, sharpening my skills, and that's a good thing. The lecture was not that hot, but what was useful was having the exercises in front of me, waiting to be done and no distractions to keep me from them. And after all that, the biggest difference I notice between Python 2.7 and Python 3 is print "foo" vs print("foo"). (Which shows you how much Python I know. But still.) I finished the exercises a few hours early, so I spent the time trying to solve the coding challenge we give new people at OpenDNS. (I didn't get that one; instead, I got the "this machine is borked in 12 different ways, please solve it" challenge.) This has been a wonderful way to stretch my brain, and work on something very very different from what I do every day. I wish work had the same sort of course for Ruby and Go.

  • Have I mentioned that I've come to love Bandcamp? Lots of excellent music, and I keep finding lots of excellent music. I mean, really really excellent music.

  • Like Hairy Hands.

  • Or Mars, Etc.

  • Or Snail Mail.

  • Also on the music front, one really excellent station I've found is Popadelica.

  • But back to Python: despite the click bait title, O'Reilly's "20 Python Libraries You Aren't Using But Should" is wonderfully informative for this Python n00b.

  • I loved showing this video to my kids, demonstrating how bacteria evolve.

  • Set up a Tor node last week for the cause.

Tags: randomupdates music programming geekdad

The obligatory mortality piece

There are three people I know that are, or have been, close to death in the last year. One had a double mastectomy last fall when she discovered she had breast cancer. Another fell down confused one day earlier this year and discovered she had stage 4 brain cancer. And the third got taken to hospital a few weeks ago because, it turns out, she's alcoholic and has pretty much destroyed her liver.

One is getting better; her hair is growing out after chemo and radiation, she's playing music again (she's incredibly talented), and seems to be nearly endlessly positive (at least around me). Another is taking things day by day, travelling when she can, trying to eat (her sense of taste has been destroyed by the radiation treatment), hanging out with her grandchildren. And the third has been in detox for a few weeks now, and has a long road in front of her if she's lucky.

One was a close friend, then we lost touch, and now we make a point of seeing each other regularly; it's not as often as I'd like because we each have our own commitments, but it's wonderful to talk to her again after so long because she's funny and talented and just a righteous pleasure to be around. Another lives far away, and for a long time has been someone I knew about rather than knew; she's a good person, but our lives are separate, joined only by the people we have in common. And the third was always a wonderful, funny person to talk to at the social occasions we ended up at together, and I loved her writing when she kept a blog, but I could in no way say I knew her.

One my wife and I have been able to help, at least in a material way. Another, my wife and I have helped someone else be able to travel to see her. And the third...well, the whole problem has only just emerged, and we have no idea what to do, or what will help, or the prospects of her being around long enough to help.

I've come to learn the way I react to things like this: shock and numbness for an hour or two, then being surprised when I burst into tears, then long weeks of worrying. I've begun to be wary of hearing about someone I haven't thought of in a while, because this is when things and people fall apart and some days it feels like the news is never good. And I've started to think about why we go to funerals, and the way grief and mourning and remembering are built somehow into our DNA, our shared heritage with all the other animals that cherish and love and mourn and, in their turn, die.

Tags: wellfuck

Observing Report -- August 5, 2016

Tonight I went out to the local park with the scope. I had a bit better list than last time and stuck to it, and ad the end of the night I was able to shut down & be home in 10 minutes. Not bad at all.

So: Quick look at Saturn to start with, before it set beneath the trees. Very nice.

Managed to split Double-Double in Lyra, but I had to use the 6mm Radian to do it. South pair easier to split than the north pair.

Followed ISS with the scope (17mm, 71x) and man, that was neat.

Omicron Draco: double star, yellow and green/blue. Not my thing, double stars, but I do like the ones that resemble Earth & the sun (blue + yellow). Colours on this one were more subtle, though.

M56: Faint. No sign of resolution.

NGC 6939: OC in Cepheus. Took a while to track this down, as it was a lot fainter than I expected. Got a sketch.

NGC 6543, the Cats-Eye Nebula: Saw this straight off, an obviously non-stellar object. Faint blue. Neat.

M92: Aw! Looks like photo of a spiral galaxy. Liked it better than M13, which I looked at next.

NGC 6229: GC in Hercules. Faint like a Q-Tip, and no resulution at all.

NGC 6709: OC in Lyra. Nice! Big, sparse, and kind of reminds m of a fish shape. Mentioned in "Annals of the Deep Sky", which I'm enjoying.

Packed it in at 12.15am. Overall, a lot better than last time.

Tags: astronomy

Observing Report - July 23, 2016

Tonight I went out to Boundary Bay with the Dob; it has been a long time since my last observing run. Here's what I saw:

  • Mars, with some detail -- probably Mare Acidalium & Siunus Meridiani. Held up well in the 6mm Radian, considering how low it was.

  • Saturn, with the Cassini Division easily visible. Also: Titan, Tethys, Dione and Rhea; couldn't pick out Enceladus.

  • M9, glob in Ophiucus, which seemed to be a bit lopsided. Hint of resolution.

  • M62, which has no hint of resolution at all. Quite low. Maybe a bit lopsided as well?

  • M24, which was nice in the 15x80 binos.

  • Beta Cephei and Delta Cephei, two very nice doubles. And of course, Delta Cephei is the prototype for Cepheid variables.

  • Gamma Cephei; unremarkaable to look at but it's 45 light years away (almost my age!) and has an exoplanet.

I looked for Pluto but couldn't get it; 12th mag was hard to see, let alone 14th, and the moon was just starting to shine in my face.

Showed a couple of folks sights through the telescope & answered their questions; saw an owl hunting.

Okay night. I was not feeling the enthusiasm tonight, though.

Tags: astronomy

Update

  • The cloud sensor is behaving badly of late, refusing to post updates. I suspect it's overheating, but it's hard to get data when the thing is across town. I had set up an SSH tunnel back to home so I could connect to it, but did the classic fail when I tried to convert it from running in tmux to running under supervisord and it didn't work and now I can't get back in. Waiting to get back to my inlaws' so I can debug it more properly.

  • But while it was working, I got it logging to InfluxDB (running on my home server over) over said SSH tunnel. Pretty sweet! And it was not hard to import all the previous stats I had as well.

  • And so but InfluxDb was running in a Docker container on the home machine, along with Grafana. Which of course led to running Telegraf on a lot of things, and collectd where I couldn't (hello OpenWRT). Which now OMG the stats. And the annotations.

  • But holy crap, Docker and IPv6 is a giant whirlwind of not-done-yet.

  • Because the kids' old laptop was, frankly, shitty, we got them a new cheap laptop and I did some complicated surgery resulting in two swapped hard drives and a new install of Debian 8 on Zombie, my home server, which is now managed nearly entirely by Chef. This was a lot of trouble -- setting up everything under a medium-weight config mgt system like Chef, I mean -- but I think it was worth it.

  • I've got the first breadboarded version of an Arduino weather station going, currently logging stats to InfluxDB. It is (/me checks Grafana) (/me checks on Arduino serial port for transmitter because receiver serial port acting badly) 67% humidity, 19.1 deg C and 1011.5 hPa and falling.

Tags: astronomy arduino cloudsensor raspberrypi influxdb grafana telegraf chef

Cloud Sensor -- Field Deployment 1.0

Today was another visit to my in-laws for lunch, and we got the cloud sensor fully deployed for the first time! Check it out:

The enclosure is a plastic container, one of a set of 6 I got from London Drugs for $15. It's got clamps to keep the lid on tight, and a rubber gasket to keep water out. I cracked the lid of the first one I worked when I drilled a hole without proper support, but my father-in-law has a drill press (one of the many advantages of marrying well) and we were able to get a second container set up.

We drilled a hole in the top for the sensor can to poke through and sealed it with silicone. I thought that would hold it in place (ie, that it would act as a glue as well) but no dice. Instead, we placed the first container -- which is smaller and was designed to nest inside -- in there as well. It sat under the sensor and kept it in place. It took a little bit of arranging to route all the USB cables, but we got it sorted out in the end.

My father-in-law crafted a shelf for the container out of some cedar planking and some steel bits he had lying around. We screwed that to the patio, then the container to the shelf. Plug in the Raspberry Pi to a nearby outlet, and boom -- we had data!

...until yesterday at noon, that is; that's when the last update was posted. (I'm starting to regret not having set up an SSH tunnel back home.) I'm not sure at this point what happened, but overheating seems a reasonable guess. We made some holes on the bottom of the container for ventilation, but it's a concern. I think the Pi itself should be good for longer periods -- I had it running outside my house here for days in a row, just not inside the container. I'll have to power cycle it and see what happens.

On the data front, I realized a while back that the CSC is only updated twice a day...which means downloading every hour is overkill. The script still runs every few hours, but now it checks whether the newly-downloaded chart's checksum is the same as the previously-downloaded example; if it is, it throws it away. And I've got the analysis script set up to convert the colours of individual squares in the CSC into cloud coverage predictions. Next step is to figure out how to store this info so I can work on it. All in all, not a bad bit of progress.

Tags: astronomy raspberrypi cloudsensor arduino

Cloud Sensor -- Alpha One Field Deployment

Today we visited my in-laws for our usual Sunday lunch, and I took along the cloud sensor to demonstrate for my father-in-law. He's a retired millwright with a strong sense of curiosity, so he enjoyed seeing it a lot. We set it up by a gazebo (?) he has in his back yard, with the Pi hanging from the wall and the sensor clipped to the roof:

Deployment Alpha One

After some clouds rolled out, it got seriously sunny. The data reflected that:

Screenshot

For the record, the ambient temperature is not really to be trusted. It kept reading in the mid-thirties, but a nearby thermometer showed nothing higher than 25 all day. And when the sensor is deployed here, it seems to register about a 10 degree higher temp for the sky; doubtless it's the combination of the wide FOV (90 degrees) and the narrow slice of the sky it can see from my front porch.

The day before I'd bought a plastic container to use as an enclosure, so we kicked around ideas about how to make it work. I'd picked it because the clipping lid seemed like it would keep out the weather quite well, especially since the lid completely overhangs the container -- but I'd forgotten to think about shedding water. The lid is recessed maybe half a centimetre, and any rain would just pool in there -- not what I want. We agreed that the enclosure definitely needs at least a flat roof, and ideally something rounded that would let rain roll off. A plastic bowl with a flat bottom would do the trick nicely.

So what worked well?

  • Wireless worked without a hitch -- very happy with this, as I wasn't sure it would reach from inside to the back yard
  • Data logging worked too, including status updates when rebooting
  • Good to kick around ideas
  • Got script working to analyze the CSC and turn it into hour-by-hour predictions; some initial ideas about how to store that data, and how to visualize that and logged temperature data

Needs work:

  • Enclosure
  • Committed API key to git without noticing; had to generate a new one

Next up:

  • Desolder header pins so eval board can be mounted with the sensor poking through the lid of whatever
  • New enclosure
  • Think about how to store CSC predictions

If you're interested:

Tags: astronomy raspberrypi cloudsensor arduino

Cloud Sensor -- We have data!

The MLX90614 eval board arrived at last. I managed to get the header pins soldered on without melting much, and hooked up to the Raspberry Pi. The default firmware logs the temperature in Fahrenheit to the serial port every tenth of a second, and I was able to read it out with screen without a problem.

Next up was adjusting the firmware slightly to slow it down a bit, write out ambient temperature as well, and to switch to Celsius. (Cue feeling bad about not using Kelvin.) That took all of ten minutes, so huzzah for that.

Finally, I set up an account at ThingSpeak.com (free as in beer, plus free as in freedom software, plus export of data whenever you like), and set up a stupid simple script to send data both to a CSV file and to, you know, the cloud. The result? SWEET, SWEET FREEDOM:

Screenshot

Clockwise from top left, that's: sky temperature (sensor pointing up), ambient temperature, and the delta (ambient - sky). It's interesting to see how smooth the ambient temp is compared to the sensor temp.

Oh, and here's a shot of how it looks sitting on top of the BBQ outside:

Pi and BBQ

Not at all weatherproof, of course, so that comes next. With the way I soldered the header pins on (all pointing up), that's going to be a challenge; I may de-solder them and have the top as bare as possible. That would let me (say) drill a hole in a Tupperware container, push the sensor through, then epoxy around it for waterproofing. As for the Pi...not too sure. I may try to mount it out of the weather, then run the sensor out under the sky.

Tags: astronomy arduino raspberrypi cloudsensor

Cloud Sensor -- First iteration

Since my last post, I've made a bit of progress:

  • I've ordered the Sunfounder Arduino starter kit, along with a Arduino Uno clone and a Mega clone (all arrived)

  • I've ordered the MLX90614 eval board plus a Redboard from Sparkfun (can't have too many Arduinos!) (arriving shortly)

  • I've done some initial playing around with the Arduinos and the accelerometer included in the Sunfounder kit, as a standin for the MLX90614. It amazes me how easy it is to get started with all of this...

  • I've grabbed one of the Raspberry Pis around the house and got it logging data over the USB serial port from the Arduino

  • Even got WiFi working on the Pi; it's an older one that doesn't have it built-in, but I've got an extra Asus N13 lying around that seems to work well

  • I've modified ttylog to include the date in its output; may not seem like much, but I'm no C programmer

Rough plan right now is:

  • Have the Arduino log once a second to the serial port; that's far too much data, but at least it'll be easy to see if it's working

  • Log that with ttylog; it'll be running under supervisor, and will log for an hour before exiting (and starting up again)

  • Once an hour, assuming WiFi works in its final location, try to rsync the log files home; if not working, pick up the log files manually

  • Put it all in a waterproof case of some sort, and find a place to plug it in at my in-laws (they've got a nice big yard)

Tags: astronomy arduino raspberrypi cloudsensor

On our way

Yesterday at work, I set up the live cast of the CRS-8 launch on the big TVs in the kitchen:

There were a lot of people watching with me. The footage from the rocket was absolutely amazing...but of course, the landing was spectacular. I found myself swearing with amazement, over and over again, I'm sure much to the amusement of my coworkers.

I'm fortunate enough that there are a string of evening ISS flyovers happening for me right now, and Heavens Above has tracking info for the Dragon as well. Sure enough, there was one tonight just before 10pm.

I went out to a local baseball field with 10x50 binoculars; nothing at all resembling a dark sky, but of course it was enough to catch the ISS as it rose. At first I thought it might be the Dragon -- it was faint and looked smaller through the binos than I've seen it previously. Of course, most times I see it much higher in the sky (and thus closer, larger & brighter). As it rose, it became apparent that it was indeed the ISS. It went slowly through the Pleiades (now that was pretty!) and right by Menkalinan (Beta Aurigae). But where was Dragon?

I stopped following the ISS with the binos and let it rise out of view -- and just a few seconds later, following almost exactly on the same track, a dim satellite came into view. Dragon! It was maybe two degrees further from the ISS than would fit in the FOV of the binos. I followed it along until nearly the zenith, then tried to catch it with the naked eye. Sure enough, there it was -- maybe 4th mag or so, much dimmer than the ISS but still visible. Although it was harder to see this way, it was so much more wonderful -- it was so obviously in pursuit of the ISS. It's amazing to see a supply ship on its way to a space station. I like living in the future.

Tags: spacex

Cloud sensor -- initial plans

So after doing some digging around, I think there's a simpler approach than using Peltier coolers, and that's using an IR temperature sensor. This guy has built his own using this approach, though he's using Arduino controllers to read them. That led me down the Arduino path, and after a lot of reading I think I've got an approach that might work.

Sparkfun sells the MLX90614 temperature sensor in a couple of different formats: bare sensor, or on an eval board. After reading that tutorial, my understanding is:

  • I can connect the evaluation board to an FTDI cable/breakout board, and hook that up via USB to the Pi. The default sketch in the evaluation board will give me temperatures in Fahrenheit once per second over a serial port. Later, I can change the sketch by using the Arduino IDE. Pro: Quick to start, USB is dirt simple, and I don't need a RedBoard or similar. Cons: Not as flexible as it would be if connected to RedBoard, since that would give it lots of expansion possibilities (humidity sensor, motion-activated potato cannon, etc.)

  • I can connect the evaluation board to the Pi via I2C. Can still reprogram the sketch later. Pro: Not really sure. Cons: Have to build my own I2C connector....not that hard, from what I can see, but I'm a newbie.

  • I can get the bare sensor (no eval board) and hook it up to the Pi via I2C. Pro: Unsure. Cons: Much more fiddly than anything I've tried before.

  • I can jump right in to Arduino and get an Inventor's Kit. I can use the bare sensor (as shown in the tutorial -- start on breadboard, package it up somehow when I'm confident it's working), or the eval board (doing something like [this example4), using I2C in both cases. Pro: Lots of room for expansion, Arduinos are fun, etc. Cons: Will take me a while to get up to speed.

Assuming I've got all that right...my inclination is to start with the FTDI breakout board and USB; that'll make the learning curve easier, and I can get the Inventor's kit later on.

I've asked on the SparkFun forum whether I've got all this right...time will tell. But getting quickly started with the USB seems like a good way to start.

Tags: astronomy raspberrypi cloudsensor arduino

Possible Raspberry Pi project

For a while now I've been wondering idly how I could measure cloudiness. My goal is to both track how cloudy it is now (and over time), and to compare actual cloudiness with predictions from ClearSkyChart.

A few days ago I came across an approach that I think might work. This person measured the current coming from a Peltier cooler when exposed to the night sky. The difference in temperature between the ground-facing side (warm) and the sky-facing side (cold) varied depending on whether it was cloudy (less difference in temp == less current) or not (greater difference in temp == more current). It occurred to me that I could use a Raspberry Pi I've got lying around to take that same approach.

Since then I've been browsing around, and here's what I've found:

I'm starting to think I've got a good approach here.

Tags: astronomy raspberrypi cloudsensor