Radio Free Meredith

version control buddhism

2009-07-15T06:02:27Z

The Git community in general seems somewhat opposed to the idea of documentation. I mean, yes, there are man pages, but they're ... interestingly sparse, and I'm sort of surprised that github doesn't have a link to a tutorial prominently displayed on the site (somewhere after you sign up, at least).

It's oddly Zen, but in that sort of annoying way where you get hit on the head with a stick a whole bunch.

Your daily dose of awesome

2009-07-15T01:01:00Z

I bet this could be used to create some pretty awesome illusions. (hat tip to tdj)

For the RPG fans; non-gamers can skip this post

2009-07-15T00:23:22Z

The setting: oWoD, Mage: The Ascension.

Imagine, if you will, a Horizon Realm such that everyone who enters it has an automatic extra dot of Mind while they're there. That is, if you're already a Mind mage with two dots, now you have three; if you're a mage with zero dots in Mind, now you have one; if you're Kindred/Garou/Fae (oh good grief...)/mortal/whatever, you also have one dot in Mind. (If you had no Arete score before, you have a temporary Arete of 1 that can only be used for Mind effects, and it disappears when you leave the Horizon Realm.) If you have a way to affect someone/something outside the Horizon Realm -- say, with appropriate Correspondence/Spirit magick, or a werewolf opening some kind of Umbral portal or whatever -- you can. (So, yes, you can sense the emotions of someone outside the Horizon Realm if you can get a lock on them, for whatever that means. Handwave it.)

What would that be like?

maradydd @ 2009-07-14T03:10:00

2009-07-14T01:11:31Z

Okay, tdj, I may be going to bed angry, but I got a great belly laugh in from the following, linked from one of the comments in the post about Dembski:

And now I sleep.

maradydd @ 2009-07-14T02:22:00

2009-07-14T00:24:38Z

By way of Pharyngula, apparently the creationists are starting to abuse information theory, not just physics, in their tortured attempts to justify their doctrine.

Of course, you understand, this means war.

ETA: /me reads the comments. Oh. Apparently creationists reject Claude Shannon's work on information theory. Infidels. They shall be first against the wall when the revolution comes.

One thing that I will never understand is why creationists believe that an omniscient God is bad at math.

Progress report

2009-07-13T12:30:30Z

Chording glove pattern prototype, version 1, three fingers and a thumb left to knit:

I am making this up as I go along, thus there are a few irregularities that I will correct in the next version when I take my notes and turn them into a proper pattern. I realized halfway up the index finger that I'd failed to knit a solid line up the thumb side (for mounting the thumb switches) like I'd planned to, and that ugly-looking line right across the palm was an experiment that didn't quite work out and that I couldn't be arsed to go back and fix. (The fishnet pattern is made by knitting two stitches together, then making a hole by bringing the yarn to the front, over and over again. The cool spirally pattern comes from having each row of holes offset from the next by one stitch, which was obligatory when I was making increases for the thumb; I forgot to alternate when I started going up for the thumb side of the palm.)

All in all, though, I'm quite happy with how it's turning out, especially since a couple of experiments succeeded -- you can rib lace after all! -- and some things that I was worried would look stupid, like the solid fingertips (for stability, and to have a place to anchor the switches), look okay after all. Since this is an attempt to figure out a pattern, I'm making this out of plain cotton, and will wire it up by sewing 30ga wire through the knit stitches (the thicker "lines" that you see on the glove), but I still want to figure out a way to work the wiring into the pattern itself, because it will look cooler and I am stubborn like that.

Barring anything weird happening, I should have the complete standalone USB keyboard glove working sometime this week. I have my wire-wrap sockets now, and have soldered in half of the discrete components (the ones I had spares of, by way of a test run); I'm going to hold off moving the rest of the circuit from the breadboard until I have the glove finished and the switches mounted and wired, but the actual wiring-up shouldn't take more than an hour or two.

I'm kind of tempted to set up an Etsy shop and sell these, though I'm not sure how much would be a fair price. The actual knitting probably takes about ten hours (spread out over a few days, since my hands get sore quickly), and the soldering goes fast; the parts are less than $20 total. Any thoughts? Would you buy one?

My Saturday evening

2009-07-11T20:52:51Z

A little cafe, lined with books and magazines; a table in the garden next to a tree-shaded trampoline; a small carafe of French wine and a volume of Chesterton.

It's a good one, this life is.

Behold my wrist-mounted USB hub

2009-07-09T20:57:20Z

Seven ports! I need to make a really short USB cable so that I can hook the chording glove up to it.

Four on the inside, three on the outside. USB-mini in the back, optional power supply.

The wristband is a padded velcro thingy that the company that a guy I know works for ordered by mistake. Normally, a smaller beige plastic holder for a barcode scanner velcros onto it; I took the velcro off the plastic thingy and put it on the hub.

My original plan was to get one of those four-port unpowered jobs, mount it in the original plastic housing, and also add slots for SD cards. I may still do that, since the guy has lots of these wristbands available. This approach means less work to do with a Dremel, but I like the idea of storage on the go. Perhaps one for each wrist, to support keyboard and mouse. (Hey, if I ever don't feel like chording but have the rig set up anyway, I can just plug an ordinary USB keyboard into my wrist!)

If I do make a custom wrist-mount, I might go all out and make a PCB for it using this approach.

ETA: Three hours in, I'm still wearing it comfortably, which is impressive for me, since I usually fidget like crazy with bracelets, watches and things like that. I did flip it to the inside of my wrist, because I realised that the titanium bracers that Chris++ is making for the sleeves of my leather longcoat will go on the outside of my arms, leaving no room for an outward-facing hub, but I think it will fit okay on the inside. Worst-case scenario, the velcro straps are long enough that if I have to, I can wear the hub on my bicep. Time to get one of those retractable USB-A/USB-mini-B cables, the clicky kind.

Photo meme

2009-07-09T14:51:01Z

Snagged from michiexile.

1.Take a picture of yourself right now.
2.Don’t change your clothes, don’t fix your hair…just take a picture.
3.Post that picture with NO editing.
4.Post these instructions with your picture.

Me and my Arduino NG, with the accelerometer I just rigged up to it.

Brief weekend update

2009-07-06T23:30:45Z

A three-day-long rave. In a field full of windmills. With an absinthe bar. Cool art; music so good that I frequently could not convince myself to leave the dance floor; truly excellent conversations about evolutionary psychology, game theory as applied to intentional communities, chemotaxis and other forms of animal communication (did you know bees' dances have regional dialects? I didn't until Sunday), and emergent network behaviours at the molecular, cellular, and human scales. I spent a good chunk of the time uncertain where my boots were and mostly unconcerned about that fact; I also lost my pants for a day and a half straight, though not the ones I was wearing at the time and not for any particularly exciting reason, but hey, that makes a good line, doesn't it? (Works better for "No shit, there I was" than for "So, there was this girl...", but hey, you can't win 'em all.)

More details later. At the moment I'm going to go soak the grime off of myself, see if a warm bath will unwind these knots in my shoulders, and slather Vitamin E cream all over the ridiculous-looking asymmetric sunburn that is my shoulders and upper back. (Note to self: do not fall asleep in full sun while wearing a tank top ever again.)

Ah, summer

2009-07-04T14:09:27Z

Crazy mad heat and humidity -- and small children on the street outside having Super Soaker wars, who are all too happy to hose me down on the way to swap out the laundry. That was refreshing.

I'm heading out in a bit to go to a techno party in the middle of the woods, where it will hopefully be a bit less oppressively hot. Happily, all the good stuff happens at night anyway. Have a great weekend, LiveJournal!

Chording glove prototype pics

2009-07-04T12:14:57Z

First off, my apologies for the lousy picture quality. We have a really good camera, thanks to foxgrrl, but I am a terrible photographer who cannot hold a camera steady one-handed to save her life. Also, unfortunately there are no macro shots, because either we don't have a suitable lens for it or I don't know how to use our existing lenses properly (the latter is far more likely). But these should get the picture (har!) across.

So, how does this thing work?

This is the circuit, all breadboarded out. Major components of the circuit are labeled -- which is basically all of them, it's not that complicated of a circuit. The whole thing is basically a USB keyboard with only seven buttons. It both talks to the computer and is powered via USB thanks to the connector over there on the right. (The production model will use a mini-USB connector.) Those four skinny red wires (thanks, wire-wrap tool!) are connected to four pins sticking out of the board, marked "Headers for USB"; the outer two are +5V and ground, the inner two are the data lines. Below and to the right of that, you'll see a couple of resistors, capacitors, and diodes. (There are actually two diodes but only one is visible.) The diodes make sure that current over the data lines only runs over the data lines (think of them as valves to hot and ground that are always turned off), and the resistors and capacitors clean up the signal going to and from the microcontroller.

The long green and yellow wires carry data to and from the microcontroller. I'll get to that long orange wire in a minute.

The microcontroller itself is an Atmel ATMega8. It's an 8-bit microcontroller with 8 kilobytes of onboard storage -- Flash, like a card for a digital camera -- and 1 kilobyte of RAM. The silver can labeled "Timing crystal" dictates the speed at which the processor runs, which is 12 MHz, or over 100 times slower than the 1.66GHz Intel Atom processor in my laptop. You can kind of think of it as the moral equivalent of a faster Apple II with less RAM, although if I needed more RAM, I could do what Woz did and add external RAM chips. (I don't, though, because the program the microcontroller is running is very small.)

Okay, so what program is the microcontroller running? Well, for that we have to look at the switches. This is actually breadboarded-circuit version 2: the twisted red-and-black wires running off the board go to the switches on the glove itself, but when I first breadboarded it up, they just went to the seven black-and-silver pushbutton switches on the board. (Those still work, and it will work without them, I was just lazy and didn't take them off.) The orange and red wires in the background, as well as the orange wire in the foreground, each connect one input pin on the microcontroller to one switch apiece. (So I'm using 7 input lines for switches.) See the pullup resistor and the ground for the pinky switch? (The ground is half-covered by the arrow, sorry about that. It's a little red wire.) Normally, the output of that switch is +5V, because the pullup resistor pins it there. (For microcontrollers like these, "pin X is off" corresponds to "high or floating voltage detected at pin X". The pullup resistors aren't strictly necessary, but they help prevent spurious input from voltage fluctuation by keeping that voltage pegged at +5V.) When the switch is pressed, the output drops to 0V because closing the switch closes the circuit to ground. Meanwhile, over at the microcontroller, the input pin that the switch is connected to detects that the input voltage has gone to 0, and the code on the uC handles the input signal appropriately.

So, the program running on the microcontroller simply listens for input signals and combinations of input signals, and when it receives one that it recognises (it has a table of input signal combinations and how they correspond to keyboard symbols -- ASCII characters, cursor movement, whatever), it sends a signal for the correct keyboard symbol over the data lines to the USB connector, which sends that signal on to the computer, which processes it the same way it would an input from a regular old USB keyboard.

The colour-coding on the wires doesn't mean anything special with respect to the circuit, by the way. They're just standard jumper wires from a kit, and they're coded for length.

People who know their way around microcontrollers may be saying at this point "but where's the FTDI chip? The ATMega8 doesn't have onboard USB!" You're right, it doesn't -- we're handling USB in software thanks to V-USB.

Also, the one thing I forgot to label is the ISP (in-system programming) headers. Those are the little gold pins (there are six, though it's hard to tell from this angle) between the microcontroller and the pushbutton switches. With these, when the board is powered up (over USB), I can plug in my AVR-ISPmkII programming device, hook that up to my computer via USB, and flash a new program onto the microcontroller. Making this was kind of hilarious, because finding six adjacent pins on a breadboard that aren't electrically connected to each other is a little difficult. I ended up completely dismembering a 6-pin piece of angled header and jamming all six pins in backward. But hey, it worked.

By now you're probably sick of my nattering about circuits and want to see what the glove looks like in action. Here you go!

There are 7 switches total on the glove: three along the side of the index finger, which the thumb presses, and one on each fingertip, which I can drum on the table (or my leg, or my head, or a nearby wall, whatever) or press by closing my hand. Yes, they are inside the glove. You can kind of see the pins for some of them; the yarn of the glove hides them pretty well, but they're fairly mechanically secure. I'll be soldering them in place on the real glove, or possibly wire-wrapping the positive and negative poles to their unused counterparts (they're double-pole-single-throw switches, meaning that each switch has two identical outputs, but only one output is actually used in this circuit), but I'd like to use this glove again next winter.

When I need to tap one fingertip switch, I can just do it with the tip of my thumb.

The centre thumb switch (yeah, I know it's on my index finger, but the thumb actuates it) is used for a lot of key combinations. With the production version I'll probably tap my fingertip on a solid surface, but I can also press my fingertip to the palm of my hand.

Another thumb-and-fingertips combination, this one the near thumb, middle, and ring. Here, I'm pressing the near thumb switch with the inside of my thumb knuckle, though the thumb tip works too.

Finally, a three-fingertip combination, made by making a half-fist. All this hand squeezing gets a little tiring after a while, sort of like working with one of those hand exercisers. I'm going to have really strong fingers if I use this approach a lot.

Sadly, no video yet, because I don't have a suitable camera for it with me. The footage would be kind of boring anyway, because I'm not very good with it yet -- the one-sentence post I typed took a good ten minutes, easily -- and I screwed up with the leads and didn't give myself a lot of room to maneuver. The next step of this project is to move the circuitry into a pair of 28-pin wirewrap sockets which I can attach to the wrist of the glove, and then it will be a lot easier to move around. I expect I'll have my camera that does video back by then, so I'll take some action vids when that happens.

This post brought to you by free software. No, really. Image editing was done on my EeePC running Ubuntu Netbook Remix, using F-Spot and UFRaw for importing and colour correction, and The Gimp for annotation and resizing. And, of course, the SpiffChorder design is itself free-as-in-speech and free-as-in-beer.

catch you in a few?

2009-07-01T16:19:53Z

It is retardedly hot and humid in the late afternoon/early evening here. I have given up entirely on the notion of pants, and still cannot bring myself to do much of anything except drink water and read. Every window is open, my neighbours probably think I'm a pervert (we have big windows), and still all I can do here is lie here and sweat.

Pics later (of the chording glove, not my pantsless self, get your minds out of the gutter), I promise, but for the moment I'm going to try to keep from melting if that's okay with y'all.

I need to find some milk crates, a hose and a couple of half-amp motors; this is giving me ideas for a stackable modular swamp cooler.

maradydd @ 2009-07-01T14:33:00

2009-07-01T12:44:49Z

i am typing this post with my prototype chording glove

project update

2009-06-30T13:12:18Z

Since my last update, I've picked up the necessary hardware to build a SpiffChorder, Mikkel Holm Olsen's homebrew AVR-based chording keyboard. The circuit is now mostly breadboarded, and one of my winter gloves has been converted into a prototype that looks scarily like something out of Serial Experiments Lain. ph34r my wire tentacles!

I have also fallen madly in love with the art of wire-wrapping. It's not a technique people use very often anymore, since soldering is so convenient and cheap, and almost nobody prototypes CPUs with discrete components these days -- we have FPGAs for that. However, it's a great way to hook up components that need a flexible connexion, such as glove-mounted switches that need to tie in to a breadboard. Wrap a lead, then wrap a single header pin, and voila -- breadboardable glove-mounted switch. (Also handy for connecting panel-mount components to a breadboard, using the same header trick. This worked great for the USB-B jack.)

joel tells me that I'm not the only one doing my part to keep wire-wrapping alive -- Steve Chamberlin did prototype his own CPU with discrete components, showed it off at Maker Faire, and taught Joel (and presumably many more people) how to wire-wrap. Keep the dream alive, Steve!

Now to figure out what I did with those 82-ohm resistors, finish that breadboarding job, and try loading Mikkel's hex image onto my ATMega8. Cross your fingers for me -- I want to take this to the hackerspace meeting tonight.

ETA: hm, that's strange, the ISP pins are definitely lined up correctly (my multimeter tells me so!), there's a 2.2k pullup on the RESET line, but I still get the blinky red LED of no love from the AVR-ISPmkII. Actually, first it's the solid red LED of no love which isn't mentioned in the manual, then when I try to load up the image via avrdude it's the blinky red LED of no love. Downloading AVR Studio now, we'll see if the official tools give a more useful error.

maradydd @ 2009-06-22T01:07:00

2009-06-21T23:16:49Z

Just now I heard a repetitive, high-pitched "mew" outside that can be only one thing: a hungry kitten.

I went out to look for it, mewed a few times to see if it would answer, and caught a glimpse of a little tail going under a car. I knelt down to look under the car and spotted it; it appears to be grey (though, in the dark, all cats are grey), and is probably about eight or nine weeks old. I'm pretty sure it's feral, as there are a lot of feral cats around here already, and we're coming up on kitten season.

It wasn't interested in an outstretched hand, but I wanted to do something for it, so I went upstairs and rummaged through the cabinets. enochsmiles and foxgrrl had brought a tin of liver pate (that no one was curious enough to eat, I guess) back from their train trip to Berlin, so I took that outside. The kitten had vanished by then, so I opened the tin and left it between two parked cars, situated so that I can see it from the bedroom window.

If nothing else, I hope the poor guy goes to sleep with a full belly. I also hope cats like pate.

ETA: wtf, half an hour later the entire tin has vanished without a trace. It better have been a cat dragging it off to eat in peace, and not the people I heard outside on the street just now. (It sounded like they were up by the corner, but it's hard to tell.)

PSA: how not to kill yourself

2009-06-21T17:21:48Z

Dear everyone,

If you are planning on committing suicide via overdose, for fuck's sake do not do it with anticholinergics. Anticholinergics are otherwise known as "deliriants" for very, very good reason. If you want to die confused and terrified while your blood pressure pingpongs around out of control, anticholinergics are an extremely effective way of accomplishing that. If you're lucky, the rapid swings in blood pressure will trigger a heart attack (which is also not a lot of fun, especially when you can't tell what's real and what isn't); if not, you're likely to end up in a coma with a failing liver.

Seriously, just don't. It will suck for you, it will suck for whoever finds you while you are still alive and it will suck for the medical professionals who end up treating you. Do yourself a favour: call a friend, call a suicide hotline. You can even call me if you can deal with someone talking you out of it with logic and being pretty much entirely unemotional about the situation.

But yeah, fuck anticholinergics in the ear.

ETA: thanks ephermata for just generally being awesome

[LJ Genie] What is this called?

2009-06-21T16:13:30Z

Dear LJ Genie,

Here is a picture of an audio cable:

I know that I can go to Radio Shack and buy a screw-together or snap-together end for an audio cable, but the friend on whose behalf I am asking doesn't need an audio cable; he needs to provide more mechanical stability for a join, and layered heat-shrink tubing doesn't look nice. Is there a name for the thick plastic part of the cable that one holds onto while inserting the male end into a socket, such that I could search for it on digi-key?

ETA: It's a strain relief boot. Thanks, grepmaster and tikiking!

Dept. of I'll Get Right On That

2009-06-18T22:23:28Z

Why doesn't the core Arduino firmware already support V-USB? 1400 bytes, wow, that ain't bad. I'd shave off some program space for that.

I will, naturally, have to see if I can compile it for Arduino in userland, but this should be a kernel thing. For the microcontroller notion of "kernel", anyway.

(clones? where are you, clones?)

ETA: thanks, internet

more idea fodder

2009-06-18T20:06:57Z

...wait, I could do 3D "circuit board" design if I could somehow produce the unholy fusion of gEDA and Blender.

If Blender lets you freehand draw on the texture of a surface, that could actually work. omgwtfbbq.

...and then you somehow convert the Blender data file into a knitting pattern, which would in and of itself be a neat little hack, since you could 3D model a garment and then convert it into a pattern ... oh cloning why are you not here yet

I forgot to take my antidepressants today. Maybe I'm actually back to the point where I don't need them anymore. That would be nice.

ETA: apt-get install blender but I am not allowed to play with it till I get more work done, it is a reward

eHuh?

2009-06-18T16:06:50Z

I'm a huge fan of Instructables, not so much eHow. The former is an amazing treasure trove of projects with a well-implemented search function; the latter has some pretty cool material too, but is plagued by pointless articles such as "How To Be [insert Naruto character here]" which keep coming up as "related articles" when I'm looking for, say, information on making a planter.

Given the, shall we say, tender age of most Narutards, I wondered whether eHow was being used as a sort of covert social channel for the Nickelodeon set -- the kind of people who would think it a major victory if their little eHow bullying page ("How To Be A Total Loser Like Amy Kunkel") or guilt-trip page ("How To Make Your Girlfriend Cry", calling the target out on recent behaviour) picked up a whole thirty hits, because that's like half the school, seriously. Searching on "how to make your girlfriend cry" came up empty, but there is How To Make Your Boyfriend Cry. For the, uh, teenage passive-aggressive gold-diggers in the audience, I guess.

No covert mockery that I can find, either, so I guess it was just a passing fancy. But I share it with you anyway, a flicker of some possible internet future.

I'm a bad person

2009-06-18T14:54:34Z

I just bought two rolls of sportweight cotton in what can only be described as "printed circuit board green".

It cost me less than 5EUR, so I'm not that bad. But I'm still giggling.

Switch placement worked well (and comfortably!) on the test glove, a winter glove that I'm not using right now. Next step is to get some junk wire and lay out the traces, as it were.

maradydd @ 2009-06-17T14:17:00

2009-06-17T12:26:53Z

For want of a needle I cannot finish making my pimped-out EeePC carrier (padded sling bag, using webbing from a messenger bag that was coming apart), and thus must hand-copy a list of parts to take with me down to my Local Electronics Shop, where I must stop on the way to my doctor's appointment later today. Or just, you know, use a backpack, but it seems awfully silly to devote an entire backpack to such a tiny piece of equipment. My sling bag will be efficient and modular. If I want to, I can clip other things to it. Neoprene will protect the laptop itself from liquids and impact damage. The weight will ride nicely in the small of my back or at my hip. Only a needle, between me and this!

But no, I will be sensible and take a backpack, because it will be faster, and that way I can make time to go to the sewing store. (Neoprene is kind of a beast.)

Oh, and I should find a good oldskool punk patch to sew to the back of the case...

Hand-knitted chording devices?

2009-06-17T02:21:27Z

Okay, knitting people, here's one for you: I want to do some work with conductive yarn. Specifically, I want to make a chording glove -- like a chording keyboard, but knitted into a glove.

After all, keys are just switches, and switches are just two contacts completing a circuit. So, imagine conductive pads leading to outbound "channels" -- insulated from each other by the surrounding nonconductive yarn.

Is this a job for embroidery, or is there a way to actually knit this?

A moment

2009-06-16T03:49:25Z

/me watches the ICMP traffic flicker by and notices a pattern in the increase in packet sizes. The derivative is an exponential function (2ⁿ), how delightful!

Bitshifting is of course simplest but the notion of increasing payload size as a function of e^x amuses me for some reason.