wiredfool

So now, I have inflicted linux on the kids. They seem to be adjusting well enough.

Their old computer, a PPC mac mini from before Ben was born, started having issues. The most frustrating one was shutting down when flash was playing on several Very Important Websites (like lego.com), but in general, it was just acting like an old creaky machine. It was set up with the parental controls on safari and mail, and a limited set of applications that they could access, just so that things didn’t get too messed up. I would have liked to replace that machine with an imac, so that it was all in one, less cables to muck with, and generally just fewer pieces. Or a mini, and they could have had the same interface again. But those were all 600$ or more solutions.

So, the lowball approach. One barebones atom MB + case, a stick of memory, usb wifi dongle, and a dvd drive from newegg. Add a drive from my extensive collection of small to med sized hard drives, Monitor, keyboard, mouse, speakers from the old computer, and suddenly, there’s a linux box. I was planning on using the netbook remix from ununtu 10.04 for the interface, but I wanted the wifi to work and some of the more modern stuff from edubuntu on there, so I’m on 11.10. The atom isn’t the most powerful machine, but it’s roughly the equivalent of a decent computer from 4 or 5 years back, and it was only $150.

Which is a little unfortunate. 10.04 was stable, and solid, but the interface there is a dead end and not going to be supported. The netbook remix launcher is gone from any later version, and the whole gnome2 interface is gone as of 11.10. Growing pains it has. It’s mostly ok, just a little confusing. I think the kids might be better at adapting to different interfaces than I am. I’m hoping that the unity interface stabilizes a bit, I’ve seen my share of bugs — layering issues, unity not working for one user anymore, crashes, 600 copies of gnome-screenshot attempting to run at once.

Web filtering is running through a combination of privoxy’s trusted whitelisting and iptables rules to redirect any untrusted user connection on ports 80 or 443 to the privoxy proxy. Firefox is also configured to use the proxy, just to make the connections cleaner on SSL, but it’s not strictly necessary. (github) Mail filtering is going to be whitelisted on the server with procmail or something similar.

I’ve also patched out the unity dash listing of applications for download when searching for an application to run on the machine. They can’t install apps, so there’s no reason to show options to install. Also, there’s no reason that this can’t be a preference somewhere, except that it seems to conflict with the goals of Canonical.

VLC plays movies ripped for the iPad just fine. (At least on the trusted user accounts. Other accounts don’t have access to the movies) Firefox hosts flash just fine, no shutdowns or other issues. Scratch runs well enough that it’s fun to play with. TuxPaint is just like it was on the mac.

I’ve now got an arduino to start on the automation of the chicken’s door. It’s only been 6 months since I put in the sliding door, and 10 months since they’ve been in the outside coop, so it’s time to do a little hacking.

Day 1, the blink example works.

Day 2, I’ve got a basic light sensor running with a random sensor from American Science and Surplus, a pull up/current limiting resistor, and the analog in ports. Helpfully enough, there’s a pretty simple example to get it all running with very little programming.

Day 3, I’m looking at the sensor levels, and trying to distinguish between dusk and night. The sensor appears to allow between 10ma and 100ma through, at an apparent resistance from to the meter of between 5k and 100 ohms. The trouble is that most of the sensitivity is in the brighter ranges, and the range where I need the resolution is in the 4.5k to 5k range, or in the 10 ma end of current. (it’s not a simple resistor, so simple approaches aren’t goign to necessarily be correct)

Using a simple voltage divider isn’t going to give me a whole lot of resolution in this range, so I may need to look at some sort of amplifier circuit (either op amp or transistor) and clip or compress the bright end of the spectrum. With one 220 resistor as the limiter, I’m seeing about 3v over the sensor at indoor night light levels, and slightly more (.1v) when covered. If I lower the resistance to 110, I’m seeing more like 3.6v across the sensor.

The basic design I’m thinking of is that if we see ‘dark’ for 15 minutes or so, I’m going to close the chicken door, and if I see ‘light’ (or increasing light) for a similar time, I’ll let it open. Thresholds and delays are TBD, since it’s going to depend on bright moons, dark rainy days, and other weather related light level issues. Also chickens. I suspect that the microcontroller has a larger brain than most of the chickens.

Other observations — I’m probably going to want another one, and probably a mini instead of an uno, so I can just drop it into a breadboard instead of using the wire sockets. On the other hand, the motor shields and comm sheids work better with the original form factor. I’m probably going to want another one to play with for lego or r/c car robotics. Or two.

Time Machine is great when it works. I had the chance to do a restore from an existing backup today, and had the original drive not been working, I would have been somewhat out of luck.

First, when importing using the migration assistant, the backup was not found. It just wasn’t there even when the network share that contained the sparse image was mounted.

Second, and likely related was that when I attempted to mount the image in the finder, I got an error that there we’re no valid filesystems on the image. This was a highly distressing thing to google, since most of the advice was to make a new backup. (and the pages without that advice are mainly q/a spam. Really bad search results. Thankfully there’s a new chrome extension for that.). I was pretty hopeful, since the original machine could access and continue to update the time machine backup. It turns out that the image opened properly once I copied it to the local drive and mounted it from there. I’m thankful for gigabit networking.

Finally, and most disturbing, there are missing files. These are files that should have been backed up, as they are the original images imported into iphoto. The databases that reference them were backed up properly, as were the thumbnails. Getting them to backup was a matter of touching the directories from a terminal window, then running a new incremental backup.

This does not fill me with confidence that Time Machine will be there when I need it.

Mood: Calming Down.
Music: Burning Down the House (Talking Heads)

Well now. That was a nice little arc welding experiment in the oven just now. And me with a nicely heated stone and pretty well proofed bread. I was getting ready to stick a couple of loaves in, and I noticed quite a bright light from the bottom of the oven. Closer inspection told me that I didn’t really want to look directly at it. It was slowly spiraling the element fading in and out of view. Lots of sparks too. A couple of minutes after turning off the oven, I decided that I’d really rather have it stop. I wasn’t actually sure if it was an arc or just burning aluminum, but after putting a soaked cloth diaper on it and both not seeing it stop and half of the element still glowing red, I had Rose kill the breaker to the stove. That and the wet cloth stopped it. I was prepared to use the dry fire extinguisher, but I really didn’t want to coat the kitchen in the chemicals if I didn’t have to.

I know that we’ve fried the element, as it’s in a couple pieces. I suspect the controller’s dead, since it didn’t kill power to the element when I turned it off. And the bread is quite interrupted. Grrr. I wanted bread.

I doubt it’s going to be cheap to fix the controller, and I really don’t think that it’s going to be cheap to replace the whole stove.

Update — Replaced the main bake element, and things seem ok. The controller seems to work, the oven seems to heat up faster, and there’s no more scary arcing. For now anyway.

Dear Apple,

Apparently you’re considering dropping the mini from your lineup.

In the immortal words of some space hero: Noooooooooooooooooooooooooooo!!!!

Seriously. These are probably my favorite desktop Macs ever. I have two PPC minis, and I’ll get Intel ones when I get too annoyed at how much faster/shinier/better my MacBook is. They are absolutely the right size and quietness for my office.

But if you do drop the mini, please consider shipping a Mac Nano in its place. Or a shuffle. I’d totally dig a Mac Shuffle with Wifi and Bluetooth, and only USB, Power and Monitor connectors.

Sincerely,

wiredfool

Ooh, this looks interesting. Yet another firmware for the linksys/buffalo wrt series routers (I have two), this one named for a vegetable. (or fruit). (whatever). The Tomato Firmware looks more shiny and has interesting bandwidth graphs and other such things built in.

Like I need a router to be shiny. It needs to work. Must not install the shiny.

Got a Linksys SPA3102 box to add some VOIP capability to the home phone, mainly so that we can cut out most of the long distance costs here. Like calling down to Useless Bay, that’s 10c/minute. Ireland, on the other hand, is 8. Voip? about 1c/min each.

It a nice little box, one phone plug for the wall, one for the phone, one ethernet for the uplink, and one for anything that you might want to put down stream. If the power’s out, it routes the phone straight to the wall. I’ve got it setup that emergency, local, and 1800 numbers go through the phone system, and anything else goes through the internet.

There are still a few bugs to work out — there’s some static that comes and goes, I don’t know if it’s a bad cable or there is some interference somewhere. It only happens with the cordless phone, so I’m suspecting interference. There’s also a lot of echo when doing touch tones over the phone system, enough that it makes getting voicemail difficult. I’ve seen some echo cancellation settings as well as some dtmf ones, so there’s a bit of playing that I need to do.

Mini Dial Plan Link Dump: 1 Manual, pdf 3