jury duty

the sacred dignity of fashion trendsI had been called to jury duty several times before, but never selected. Steph is an attorney, Charles was an investigator, people in my family have gone to jail, and I’ve seen enough movies to know that the police can be compromised (Blade, for instance).

So I was confident I could weasel out of my latest summons, and all the more so when I learned the case was a DUI. I stood before the judge and stoically recounted the times I had found myself on the hoods of thoughtless motorists. Why, your honor, I half-chuckled, I would have been standing here in November if a driver hadn’t broken my collarbone and driven off.

But do you think that experience would interfere with your ability to judge this case impartially?

No, I replied. I held my gaze steady and locked on the judge, confident that, in the periphery of my vision, the attorneys would see the zeal for bicyclist jihad that was blazing in my eyes. I would surely be struck from the jury pool, freed by my victimhood.

Well, no such luck. I was selected for the jury and spent the next day listening to a very brief trial. The facts were these.

Around 3 AM on a Thursday morning, the defendent emerged from a cab on a side street in Adams Morgan. She walked past three bike cops–unsteadily, though perhaps not staggering–and got into her car. Moments after she had started the engine, an officer was tapping on the glass, asking her to get out. She had some trouble producing her license, and left the car in gear when she first tried to emerge. It lurched and she had to hurriedly swing her body back inside to brake. She never left her parking spot.

She admitted to having a drink, but said she thought she was okay to drive. She then failed the first of three field sobriety tests–the horizontal gaze nystagmus test, the one where the officer makes you follow a point with your eyes–displaying six out of six potential indicators of intoxication. She then began to fail the next test (walking a straight line), but refused to complete it, saying it was too late in the evening. She refused the third test as well (standing on one foot), and so was cuffed and taken to the Third Distict station. There she refused to use the breathalyzer, acknowledging on a form that this meant she would lose her driver’s license for twelve months.

So. That was the prosecution’s case. The defense took its turn, but was unimpressive. There was some inconsistency in how the testifying officers described their physical locations on the street relative to the defendent. The newest cop was caught claiming that he could smell alcohol on the defendant from fifteen feet away.

Here, the defense convinced me: the uniformity of the police claims of alcoholic odor and bloodshot eyes were suspicious. I’m not trained to watch for such things, but I don’t think I’ve noticed someone smelling of booze more than a handful of times; other signs of drunkenness seem much easier to detect. In rooms where videos like this one are shown, I have no doubt that officers are told they should always claim these unverifiable impressions.

The extent to which the police had been trained for the courtroom was subtle but impressive. The defense asked if the testifying officer was familiar with a textbook about field sobriety tests; in fact he not only knew it, but could name distinctions between its editions, identified to the month. The tech from the station was eager to explain the difference between the semi-discredited Intoxilyzer and the new and faultless Intoximeter.

More than this, their affect and conduct made an impression. The steady eye contact with the jury; the friendly confidence; the polite references to the defendant; the lack of mistaken use of gestures or imprecise speech, knowing that they were participating in the creation of a written transcript. I couldn’t help wonder whether the second officer–an MPD veteran of several years–was putting us on when he appeared uncertain about how to approach the witness stand or navigate the courtroom’s other logistical minutiae. Surely he had done this exact thing dozens of times in this very building, probably in this very room.

The defense amounted to little more than nitpicking. No witnesses, brief cross-examinations. We went to the jury room without much doubt about the evening’s events, but unsure whether they were enough to produce a conviction.

Per the judge’s instructions, two standards had to be met. Was the defendant operating the vehicle in DC? The law says that you merely have to be “in control” of a vehicle. It doesn’t even have to be running! Pushing a car out of the snow or leaving your hands on the steering wheel can qualify. We all agreed that this criterion had been met.

The other standard related to the defendant being “under the influence of alcohol”. This means impairment of her ability to operate a vehicle to an extent that could be perceived. There is no specific threshold or test that divides impairment from non-impairment.

Interestingly, the judge’s instructions stated that the defendant’s refusal to take the breathalyzer could enter into our consideration. Specifically: this refusal could be interpreted as evidence of “feelings of guilt”, which could in turn be taken as evidence of actual guilt. Steph feels this is unconstitutional, and I admit that it felt a bit fishy to me, too. But it was plain as day in the instructions.

The jury quickly settled into a 10-2 split favoring a conviction. One dissenter remained quiet, but the other was happy to argue on the defendant’s behalf. I sat next to this gentleman during the trial, and found him to be friendly and pleasant. But he was a bad juror. He seemed used to being afforded respect and being celebrated for his cleverness. At home I suspect he is considered a man of erudition. Alas, his arguments betrayed an imprecision of thought and an eagerness to use the proceedings for a sort of role-playing.

Among the arguments he brought to the table:

  • “Only one of three tests was administered; that’s 33%. And we know that test is only 77% accurate. That’s only a 25% chance she was impaired!” [In fact, that 77% figure was quoted for observations of 4 of 6 indicators at 0.1% BAC; the defendant displayed 6 of 6. Also this is not how statistics works.]
  • “We have her signature on the form where she declined the breathalyzer. Let’s ask for a current signature and compare [to look for differences due to drunkenness].” To my embarrassment, a note was passed to the judge asking for this new evidence, which he politely rejected.
  • A suggestion–seconded by several other jurors–that we consider the defendant’s appearance and decide whether she looked like an alcoholic. This was particularly revolting to me, and I said as much.

Basically, justice is terrible. Many of the other jurors weren’t much better, confusing facts and engaging in inappropriate flights of speculation before being shut down by their peers.

I don’t know that I was so much better. I could assemble relatively cleaner arguments, but I left the courtroom feeling equivocal about the presumption of innocence and reasonable doubt; and I was saddened by the likelihood that the police had watched a drunk woman walk to her car, patiently waiting to stop her until she had–just barely–committed a serious crime. I walked into the jury room thinking “guilty”, but the sense of the majority cemented this from opinion into belief. At some point I stopped bothering to dismantle bad arguments coming from those on my side.

And the rhetorical skills lacking in some other jurors lacked amounted to little more than a clumsiness at manipulation. At one point we received an answer to a question we had asked the judge, and the answer undercut the argument for exoneration. My fellow jurors immediately pounced on the hold-out, browbeating him with this new fact rather than giving him space to admit a change of heart while retaining some dignity. I found myself waving them off, even though I agreed with their position. I wanted to get out of there. I was ready to bend the conversation to that need.

The holdout’s ego survived this attack, and he reluctantly agreed to a guilty verdict. Besides, he noted, he had a lunch appointment to get to. A verdict was read to an impassive defendant, whose life became much (but I hope not disastrously) worse. We were thanked for our service, collected our $4 per diems, and walked out into the cold, mostly confident that we had done something.

lyrics sites are still kind of dumb

Tim Lee is 100% right to situate Genius within a long and failed utopian tradition of annotating the web.

Earlier today I complained about one class of hopeless apps that often applied for grants from Sunlight. It eventually became clear to me that web annotation tools were another. That’s not to say that they weren’t cool–heck, we even built some ourselves. But it’s definitely a low-percentage play.

Consequently I think that Genius’s efforts to expand into a news app are probably hopeless (there’s no money in news apps to begin with, and probably even less in this one). But that doesn’t mean the site hasn’t done something clever.

In particular, they’ve paired excellent technical execution with even better timing. It seems clear that lyrics sites can make at least some money–the web is littered with heaps of garbage like azlyrics.com. They’re benign parasites, the geothermal vent-hugging tubeworms of the internet, thriving in an ecological niche made possible by larger, more popular cultural phenomena. The Genius guys picked just the right genre (hip hop, with its closely associated and copyright-averse mixtape and sampling cultures) and just the right moment (when noncorporate reproduction of others’ IP became a part of everyone’s daily communication habits). This let them become a more polished operation than the fly-by-night SEO lyric farms that had lived and died by the whims of record company lawyers and Russian webhosts. And that, in turn, has let them take investors along for what looks like a pretty fun ride.

The calculated executive outrageousness and appearances on various future-of-news plenaries are meant to distract you from a business model that has always been founded on accidental Google traffic and encouraging visitors to click on popup ads.

Perhaps there’s a plausible escape route. But what seems more likely is the story we’ve seen again and again on the internet: somebody builds a business next to an existing one, the incumbent waits until revenues appear and then throws a fit, and the courts decide if it’s Napster time or Spotify o’clock. Usually it’s a more interesting underlying industry and a less compelling product. But we’ve been here before.

bsg0043

badness

Vox has a nice piece about the nonsensical nature of “detox” diet regimens.

The idea can be opened up a little more, though. I think “auto-intoxication” is a mental tic that goes way beyond our physical well-being. That we are polluted with something that diminishes us is a pervasive kind of neuroticism, one arguably present in everything from dietary concerns to Scientology’s body thetans to the doctrine of original sin. I’ve come to believe it’s an evolutionary feature of humans, one related at the very least to our tendency toward spirituality and perhaps even to the kind of mammalian restlessness that we call “work ethic.”

When applied to food and health this drives me nuts, in no small part because I have had to grapple with my own relatives’ inventions in this genre. For years dad wouldn’t go to a conventional doctor for his disorientation and memory problems thanks to my aunt’s diagnosis of mercury poisoning, which proved robust despite various disconfirming test results. It doesn’t take much to sustain these suspicions. In his case, merely anecdotal observation of how symptoms (sometimes!) responded to nutritional supplements and, perhaps, the ecclesiastical satisfaction to be had through near-hourly observance of my aunt’s prescribed chelation regimen.

In the last few days I’ve seen these mystical habits of mind on a less worrying scale, as a guy I like and respect translated his negative opinion of Wal-mart–developed, presumably, because of their effects on workers and the economy–to guess that the chain’s produce might be particularly riddled with glyphosate, the purported negative health effects of which he had recently been reading about.

Some of this is probably due to the media’s translation of statistical accounts of epidemiological phenomena into stories that are causally simple enough to be understood by everyone. Something does something or it doesn’t; confidence intervals and statistical significance are the first thing to go when we compose a mental synopsis.

But I think much of it is in-built: an inherited need to seek personal purity (even if only in relative terms). I suppose there are worse ways for this to manifest than time spent in Whole Foods.

advertising seems hard

I was saying something dumb on Twitter and stumbled across an old post about the constricting array of tools available to advertisers as consumers become ever more attuned to manipulation. I’m now less sure that this idea isn’t just a product of my own limited imagination. Still, an observation in its favor:

banana republic instagram ad featuring a puppy from the humane society

This is the first Instagram advertisement I’ve seen that attracted anything less than intense vitriol in its comments (“why the fuck is this in my feed”, etc). And you can see why: it’s barely an advertisement at all. It’s just a photo of an adorable puppy (people like puppies) and an invocation of the idea of saving puppies (people like pretending that media consumption can be a form of altruism).

In one sense: congratulations, Banana Republic #brand managers! You’ve cracked the code. This is going to make for a great SXSW panel.

In another: what’s the point? I won’t pretend this ad hasn’t manipulated me to some degree. I no longer have enough faith in human cognition to muster that level of self-flattering defiance. But even if some part of me now feels better about Banana Republic–if we grant that some hypothetical fMRI study could now show a slightly stronger correlation in metabolic activity between my Sweater Cortex and my Puppy Striatum–how easily can this be converted into cash money? There is, after all, a gulf between getting someone to agree that a thing is nice and getting them to give you money for it. I doubt that Instagram clients are keen to reinvent the nonprofit fundraising industry.

Perhaps this boils down to the same old unanswerable questions about mindshare and brand awareness–ideas that, to an untrained observer such as myself, sure sound like the kind of bullshit you invent when you can’t show your boss any concrete results.

And yet every year the same Coca-Cola ads featuring Santa and, more recently (and pan-religio/culturally) polar bears–issued, presumably, from the vast bunker beneath the Masonic Temple in Alexandria. They must think they know something we don’t about making us know things we don’t think we know. Right?

terror from the skies

Steph got me a quadcopter and it’s awesome.

I haven’t gotten to the point of the manual where they teach you how to add a horrible electronic music soundtrack, so this will have to do for now.

using others’ information

stylized photo of malcolm gladwell

There are defensible reasons for disliking Malcolm Gladwell (too glib!) and bad reasons for disliking him (too successful!). But this is the reason that irritates me the most:

Gladwell has used information from others without attribution, often in language that closely resembles the source. […] There is one possible escape clause for Gladwell here–something that could absolve him of any guilt or plagiarism charge. Many journalists–especially magazine writers–have for decades subscribed to the idea that the use of established facts does not require attribution. […] I’ve long been troubled by the use of unattributed material with the excuse that it’s already been disseminated and established. When does the need for attribution fall away? Where do we draw the line?

The example cited is about the specifics of an old public works project–a particular tunnel’s length and cost, its difficulty and progress. It’s taken from a hard-to-find book of economic history by John E. Sawyer, which was published in 1952. Gladwell could have and probably should have provided attribution to Sawyer–it’s hard to see what the downside would have been.

But it’s also hard to see the downside to what happened. Jack Sawyer has been dead for twenty years. Gladwell’s offense, if there is one, has been committed against our collective sensibilities, not against a person.

There are good reasons to consider plagiarism bad. Enforcing rules of fair play within the writing professions makes sense as an economic necessity. But proof of copying is not proof of deprivation. Adding a moral dimension to the prosecution of victimless crimes requires an unpleasant meanness of spirit.

I feel a bit sad whenever someone is drummed out of office for, say, a lifted graduation speech or some other misappropriation that isn’t the crux of their job. I’m sure that I, too, would be disappointed to learn that the greatness of words I admired was borrowed, and I would want to punish the speaker, to reclaim my misapplied esteem. But why? We can make all the words and esteem we want.

The idea that facts belong to someone is crazy. It’s a fiction we use to ensure that fact-creators keep creating facts. The usefulness of this game of make-believe is obvious enough to have been pithily expressed hundreds of years ago. Maybe it’s because it’s such an old story that so many people have started to believe it’s real.

Perhaps I’ve been radicalized by work–the nonsensical nature of database licensing agreements could drive anyone mad. Ignore, for a moment the impossibility of conjuring a coherent line between “a bunch of facts” and “a legally protected database”. There are other problems!

These licensing agreements invariably prohibit some uses of the knowledge contained in the database, and these prohibitions rarely make much sense. When read with eyes too inexperienced to know what not to see, the text often outlaws the very thing the database is meant to facilitate. When you ask the salesperson about this, they assure you that what the agreement says is not what it means. And they’re right. What it means is: make sure we can keep getting paid. You can let people have this information but not, you know, let them have it. Make sure you tell it to them in a way that ensures they will pretend not to know what they know.

I don’t begrudge this approach. What else can they do? These databases are expensive to create and maintain, and we should all be glad that someone is doing this work. It’s a fiction that we navigate and treat with respect. But it is pretty absurd.

When the process is complete–when the tunnel is done, its specifics related, its chronicler dead–we can drop the pretense. And we should. It’s disappointing to see those who esteem ideas arguing that they ought to be more scarce.

I went to UVA

It was the best school that I could afford, and I think it gave me a good education. But it was never a great fit for me. I met some people there that I really liked and many more that I didn’t. I identified with these kids, not the ones in ties at football games. I seemed to be the only person thrilled that Stephen Malkmus had gone to UVA (including Mr. Malkmus).

When I read the Rolling Stone article, I believed it. I had known and disliked the callous frat culture. I had been disgusted by the university judicial system’s failure to grapple with the beating of Sandy Kory, and was unsurprised to hear that it had failed Jackie, too. And I believe that sexual assault is an enormous problem on American college campuses. I didn’t bother to finish reading the story, to be honest. It only took a few hundred words to bring me to despair, and I knew what the rest would say.

When critics raised doubts about the story, I believed them, too. I knew and was friends with people in frats — the stoner and geek frats, but frats nonetheless. I even rushed one, briefly! At a school like UVA these connections to the Greek system are all but unavoidable, particularly if you are underage and keen on drinking. Although their culture was sexist and aesthetically distasteful, it never seemed violent to me. Individuals behaving despicably was and is all too believable. But a premeditated, group-level endorsement of predatory violence seemed unlikely, particularly given the frats’ years of experience projecting the most upstanding image they could manage to help keep the party going.

And of course there were other problems, some of which will only make sense to alumni. Gawker’s dismissal of the timing of fraternity rush as a salient factor seems unwarranted, for instance.

I was unsure what to think. Because of conflicting evidence and heuristics? Only superficially. In truth, it’s because I have competing self-conceptions that can justify themselves in different ways depending on what we collectively decide this episode’s moral will be. I am a supercilious iconoclast who disdained the frats, even as he let them buy him oceans of beer. And I am a UVA graduate who thinks but does not say the phrase “public ivy” and who doesn’t want people to think of rape when he tells them where he went to school.

My thoughts are ambivalent but they are uniformly tainted by emotion and vanity. And although their reasons are different, I think this true for most people discussing this case, and everything else, on the internet.

How could it be otherwise? We don’t have enough information to judge the truth. There are endless explanations and additions that could modulate every atom of the narrative, but no amount of reporting is likely to let us access them satisfactorily. Luckily, we don’t care that much. Instead we will settle for asserting, by fiat, how the world must have worked in this instance, reasoning from first principles: we are good, and the people we dislike are bad, and reality, in the long run, must surely reflect this distinction.

I no longer believe that I have a right to hold an opinion about what it was or when it happened, but I am pretty sure that something very bad happened to Jackie and that she’s suffering because of it, and because of this she deserves sympathy and help. I believe it’s her right to go to advocates for support or to the police for justice, but I don’t believe that the rest of us deserve to continue gawking at her horror — particularly now that the conversation surrounding it has lost any plausible claim to preventing future violence.

genies, bottles & GPS

Over the past few months I’ve been idly picking my way through You Are Here, a review copy of which was generously sent to me while I was still at Sunlight and in the wrong industry to review it. It’s enjoyable!

Inertial navigation — tracking position by keeping a careful tally of acceleration (originally, by using gyrocopes) — is particularly badass.

giphy

This is even more amazing now that we have solid-state accelerometers in our phones and wiimotes and laptops.

The RoomScan app uses these techniques to let you build accurate models of interiors by sliding your iPhone along the wall. Using it during the home-buying process was an I’m-living-in-the-future moment. (Making light saber noises is also good.)

The two things that jumped out at me from the book were about the GPS system and the silliness of politics. First, on the popular myth that Ronald Reagan’s bold vision is the reason the military-built GPS system was opened to civilian use:

reagan_gps

And second, on the idea that Bill Clinton’s brave decision to unlock the GPS system’s full precision to civilian uses is what delivered our current era of accurately-positioned benefits:

coast_guard_gps

It turns out various other agencies were successfully building systems to defeat selective availability, too, notably including the FAA. But good for you, Coast Guard. This might have been the highest-altitude DRM system of all time, but it didn’t work any better than the rest.

Our positioning is going to get even better, incidentally. iPhone chips can already use not only GPS signals but those of GLONASS, Russia’s competing (and never-crippled) system. The EU is launching Galileo, which promises to improve accuracy even further. In fact, its (paywalled) commercial version will allegedly deliver precisions of just a few centimeters.

Flickr users are wrong

creative-commons-flickrA lot of people are upset about Flickr’s plans to begin selling prints of user photos that are available under Creative Commons By-Attribution licenses.

Some people have told me that Flickr’s plans bother them because it changes their understanding of their relationship with the company. Companies are not people, and I will gently suggest that it is unwise to cultivate emotional relationships with them. Doing so invites disappointment or manipulation.

So let’s look at the other reasons that people are upset about this. I think that many people are either behaving irrationally or do not understand what free culture licensing means.

  1. Flickr users are under no obligation to add a Creative Commons By-Attribution (CC-BY) license to their work. It is and has always been easy for users to retain complete control over distribution of their photos if they care to do so.
  2. Just as easily, Flickr users can select a CC-BY-NC license, which allows reuse of their work for noncommercial purposes.
  3. Right now, CC-BY images on Flickr are often used for various commercial purposes. There is nothing stopping anyone, anywhere, from selling a print of your CC-BY licensed work, nor from downloading your CC-BY licensed photo and making a print for themselves.
  4. Flickr’s sale of prints does not deprive photographers of their work or money. Users have the same ability to use their work that they always had. The vast majority would never have taken the steps necessary to profit from their work, so print sales do not deprive them of money. When a user really expects to sell prints, they should avoid Creative Commons licensing, which, as I’ve mentioned, is easily done.
  5. Flickr’s sale of prints provides benefits to other people. People who work for and own Flickr make money. The vendors producing and delivering the prints make money. And people who buy prints get to enjoy works of art.
  6. Some people have earnestly-held beliefs about this last point amounting to a bad thing. But not very many (it’s a difficult trick to pull off without also rejecting most aspects of global civilization). Most people think these are good things.
  7. I suspect that many Flickr users agree that the things in point 5 are good. It’s just that they’d like to have control over when they happen. Maybe it’s okay for the local coffeeshop to use your photos on a flyer, but it’s not okay for Archer-Daniels-Midland to put them on a billboard. I suspect this is how a lot of people feel, because I used to feel this way, too. But if you insist on control, those good things in point 5 usually won’t happen, because it’s too hard to ask for permission every time you want to use a piece of culture. This is one of the main reasons why Creative Commons licensing was invented.

Open licensing is about giving up control so that other people can benefit. That’s all it will cost you: control. Having control feels nice. But you should ask yourself what it really gets you. And you should think about what others might gain if you were able to let go.

Think carefully and decide what you need. No one is going to make you tick that Creative Commons box. But when you do, it’s a promise.

LEDs for halloween

I’ve continued to drift away from my commitment to dressing as villains. In my defense, Cyclops is kind of a jerk.

I worry that I’m beginning to stagnate: my palette of duct tape, under armour and LEDs is flexible enough for a variety of comic book characters. If augmented with adhesive velcro strips and the choice of a pouch-laden Rob Liefeld character, it’s even sort of convenient.

The LED components are always a hit, and I’ve seen more costumes incorporating them in recent years. I’ve added light to my costumes with a variety of different systems in the past, but they always had shortcomings. This is the first year that I achieved a well-engineered yet simple implementation, so it seems worth writing up how best to do it.

LED strips

China now produces these in great volumes, and they’re both cheap and easy to work with. Tons of different colors and configurations are available from eBay and Amazon, invariably arriving on black plastic spools and with peel-off adhesive backing. Besides color, you’ll have to decide on brightness, which varies both LEDs per meter and LED type, and waterproofing. For a halloween costume, pretty much anything will be fine — which is to say blindingly bright.

The strips can only be cut in certain spots, but these are clearly marked. Solder tabs are present if you want to connect strips together. You’re going to need a soldering iron to connect the strip to power, but it’s about the simplest soldering job imaginable.

Power

The strips aren’t just LEDs: they also have integrated resistors that are rated for 12 volts, presumably because this is the voltage at which automotive systems run. That’s what you’ll need to supply to the strip. You have a few options:

  • Batteries’ voltage is summed when wired in series. Alkaline batteries like AA cells, AAA cells and D cells are all 1.5 volts per cell, meaning that 8 placed in series will give your LEDs the power they need. You can find appropriate battery cases at Radioshack or eBay (you might need to chain two four-battery cases together). This is arguably the easiest of the approaches listed here, but also the shortest-lived and the one most likely to cause problems if asked to power too many LEDs (particularly with AAA cells, which I don’t recommend).
  • Lead-acid batteries are rechargeable, can hold a ton of power, and come in 12 volt or 6 volt varieties. Avoid the latter, buy a cheap trickle charger, and connect directly to your LEDs. The downside, as the name suggests, is weight (and price — a small battery will probably run $30). Any lead-acid battery is likely to be 10 or 15 pounds. For the right costume, this is no problem. For others, it’s a huge pain in the ass. If it suits your needs, though, a lead-acid battery can be a handy thing to have around: keep one charged and one of these doohickeys on hand and you’ll be able to power your cell phone for a solid week when civilization finally collapses.
  • Lithium-polymer USB batteries are rechargeable, pack a lot of juice, are compact and lightweight, and can now be had for less than ten bucks. They’re ideal for costumes, and they often wind up being useful cellphone supplements after the holiday. Their downside is complexity. USB power is always 5 volts. That’s not enough for a 12 volt LED strip. Chaining these batteries together isn’t a great idea, either. There are already electronics in play in those enclosures; and anyway 12 isn’t divisible by 5. We need a way to turn 5 volts into 12.

Boost converters do this pretty efficiently, and cost just a few dollars on eBay. You’ll need a few more things to use them, though: wirecutters, a USB cable you don’t mind ruining, and a multimeter. This last tool might sound intimidating, but a crappy $10 multimeter will work just fine.

At this point your mission is to cut the USB cord in half and expose conductive portions of its four wires. Plug the USB connector into the battery and use the multimeter’s probes to test the wires until you find a pair that gives you a reading close to 5 volts (it might not be exact, but it should be within a tenth of a volt or two). If your USB cable was designed by good people, these wires will be red and black, like the probes of your multimeter almost certainly are. But maybe they won’t be. I’ll assume they are.

Disconnect the USB plug from the battery. Then solder the USB wires onto the boost converter. Red is positive; black is ground. They go to the IN(+) and IN(-) solder terminals of your boost converter, respectively.

Now reconnect the cable to the battery and use the multimeter to probe the output terminals of the boost converter. There’ll be tiiiiny screw on top of a plastic box on the boost converter. Turn it while reading the measurement from the multimeter until it reads twelve. It can be tough to do all of this with only two hands, so finding someone to help is recommended.

Once your boost converter is set to twelve volts, you can solder your LED strip’s connection to the output terminals. Simple.

You can avoid the multimeter hassle by buying one of these units and using its integrated display to set the voltage.

This is both more expensive and a waste of energy (the display will remain on while powering your costume). It’s also not something I’ve personally tried — I’ve only used these to step down voltage from 12 to 5, not to step it up. I think it should work, but I can’t make any guarantees.Either way you’ll need to chop up a USB cable. And a basic multimeter is a handy thing to have around.

How Much Power?

It’s a drag, but if you’re powering more than a dozen LEDs, you should do at least a little math to ensure longevity and safety. Batteries can get dangerously hot when they’re drained quickly. Besides, you wouldn’t want to run out of power before the end of the party, would you?

We’re concerned with amperage — milliamperage, to be more precise. A liberal estimate of an individual LED’s power consumption is 30 milliamps. This level of current draw, held for an hour, equals 30 milliamp-hours (mAH). Conveniently, this is also the unit that battery capacity is measured in.

If your battery assembly’s output is 12 volts, the math is really easy: just divide the mAH rating of a your alkaline battery type by the number of LEDs in use multiplied by 30. A typical AA battery might hold 1200 mAH (check the label). Given that rating, a 12-volt assembly of them (8 in series) could power 40 LEDs for an hour.

If you’re using a single lead-acid battery, it’s just the same, except your battery’s capacity might be measured in amp-hours. One amp-hour equals 1000 milliamp-hours. That means a 6 amp-hour lead-acid battery could power 200 LEDs for an hour.

With varying voltages, like we’ll encounter with a USB lithium battery, things get slightly trickier, but only slightly. We need to figure things out in terms of energy, not just current — that means watts, which are amps times voltage. Here’s how it works out:

(5 volts * USB battery milliamp hours) / (12 volts * number of LEDs * 30 milliamp-hours)
=
number of LEDs

The boost converter we use with the USB battery isn’t perfectly efficient, so we should include a fudge factor. Let’s be conservative and say it’s only 90% efficient:

(0.9 * 5 volts * USB battery milliamp hours) / (12 volts * number of LEDs * 30 milliamp-hours)
=
number of LEDs

A small USB lithium battery might hold 2400 mAH (the packaging will usually say). Using the above math, that means such a battery could power 30 LEDs for an hour.

Of course, you probably want to power your costume for more than an hour. In fact, you should make sure of it: asking a battery to dump all of its power in an hour is fairly aggressive, and might make it heat up more than is comfortable or wise. Use the above to figure out the capacity you need per hour, then double it. Remember, you can always swap out batteries. Or, for the alkaline and lead-acid otions, you can increase capacity by adding more cells in parallel (don’t do this with the USB lithium option — just plug a new one in, or power different sections of LEDs from different batteries).

The above estimates are conservative. Boost converters are generally more than 90% efficient, and the types of LEDs I’m suggesting you use generally draw 15 or 20 milliamps, not 30. But it’s good to employ a generous fudge factor. I’ve always been pleasantly surprised by how long my batteries hold out. You’ll probably want to give your rig a test run before the party, anyway.

Fading

The first time I tried to dim the LEDs in a Halloween costume it didn’t work very well. I had attached a potentiometer: a knob that can add resistance to a circuit when you turn it. Increasing the resistance lowers the voltage that gets to the LEDs. A lower voltage does dim LEDs, but the behavior isn’t very smooth. At first the change is almost imperceptible, then it’s very sudden, and then the LEDs just turn off completely. This is because LEDs emit photons in response to voltage in a nonlinear way; even worse, humans perceive brightness in response to number of photons in a nonlinear way.

The solution is not to alter the brightness of the LED, but to change its duty cycle: how much of the time it’s turned on. If an LED is only turned on every third microsecond, it will appear 33% as bright as if it were on steadily. LEDs turn on and off very quickly, so it’s easy to make them strobe so fast that the human eye can’t notice the flicker.

The way to do this is beyond an introductory blog post, but the short answer is: a MOSFET, an Arduino, and the analogWrite() function. The first two can be had for less than $5 combined, and the last is free. If you decide to try this but have no idea what you’re doing, get in touch with me and I’ll try to help.

A nice side-effect: by adding an Arduino you can easily start programming strobing or fading effects. You could even make your costume respond to the partygoers around you.

EL Wire

LEDs aren’t your only options for lighting a costume. Electroluminescent wire, strips and panels are fairly cheap and generally come with their electrical systems prebuilt, thanks to their unusual power requirements (very high voltage and frequency alternating current at very low amperages). Those power supplies generally run off of just one or two alkaline batteries and can last for many hours.

The downside to EL systems is how difficult they are to manipulate. EL wire and panels can be cut, but they can’t be spliced without unusual tools and more skill than I can muster. The power supplies also tend to be made cheaply, and when they are they emit a quiet but high-pitched whine which might be annoying in environments that are supposed to be silent and spooky, like a haunted house.