Holy crap am I tired. Suffice it to say that learning to use a laser cutter was pretty awesome: I now have a chassis for my clock, and a broken key chain QR code. Seriously, bass wood will not hold up to hiding in your pocket for half a day.

First time at NYC Resistor, too. Very cool hackerspace, not sure if it’s bigger than A1L or Metrix. Oh well.

I would post a picture of that clock chassis, but wordpress is barfing on me and I don’t want to deal with it right now.

I'm going to try and focus on homework, maybe go to sleep early for once. Going to sleep for 6 hours for 4 days in a row can't be good... On the other hand, always waking up at 9AM seems to have cured my insomnia. Either that, or getting 6 hours of sleep means I'm always tired. Eh.

Here’s a thought: similar to how martial artists strive to not use their skills, printmen should strive to not use their printers.

Why do I say this? Well, printing is based on the idea that we can make any object our minds can think of, to fill needs that aren’t so easily met by the larger market; moving fulfillment of the long tail out to the long tail, in a sort of lingo-speak. Us print-dudes* believe that this is a net win, that the costs of printing adoption and sustaining a printing public are less than the benefits of having more creative power and flexibility available in the goods available to the public.

So if printers are a good thing, then why the proposal that print-dudes try not to use them?

Back to my comparison with martial arts**: the master and the novice know that their art is a last resort. To think otherwise would mean an abuse of power, a violation of the societal trust that restrains people from using firearms to settle petty disputes (usually). The difference between the firearm and the martial art is about 10 years, assuming that martial arts are among those things that take 10 years to really learn; then, one can imagine that a martial artist would struggle with himself over whether to invalidate all the effort put into learning the art, versus settling a dispute turning nasty in the quickest way possible.

Now, what does this have to do with us print-dudes? Now, I can’t add up all the externalities, but I am quite sure that printing is not a net-green-gain. For example, the reprap*** runs stepper motors and a heating element for a couple of hours in exchange for one object. True, it is custom made, but that’s still a whole ton of energy for one object. The reprap has other things going for it conceptually****, but the point is that if we can go without it, we should. Better would be recycling objects: not melting printed parts back down to filament, but re-purposing ready-made, old objects, and scraps to fill functionality we normally think ‘3D printer’ for.

So my thought went something like that. Meh.

• I’m trying to figure out what the signifier for print-men should be: print-men seems somewhat sexist, and printer refers to the actual machine itself. Hmm…

** Note that I am not a martial artist. You should essentially assume that I am bs’ing this entire paragraph.

*** I’m building a reprap, no offense intended. Also take this as a plea to ignorance about the true power consumption of the reprap.

**** On a different note, printers like the reprap can help decentralize the economy to the point that regions can nearly decouple from each other. Maybe I’ll write on this particular vision later.

So I’ve been a lazy butt, and I haven’t been keeping up with my favorite pet blog as well as I should be. Over the last week or so, I’ve been screwing around with interfacing a wii nunchuck with my laptop. Have some videos:

http://www.youtube.com/watch?v=koXZ20MdEt4

http://www.youtube.com/watch?v=2ro-Lz3BUOo

They’re pretty self explanatory. I’ve also done some work with moving the mouse with the nunchuck, but I haven’t actually gotten off my lazy butt and recorded it for a humiliating posterity yet.

The next step is to… do nothing with it. It’s very much less useful as a HID device than I thought it would be, to the point that I would curse working with such a thing if I had to use it as a mouse for every day activities. It might be useful as a gaming device (as Nintendo intended), but I can see the intention of the nunchuck as an accessory showing itself in such a function. So, it would be better to just use the entire Wiimote as an input device, or to use the nunchuck as a control device for the arduino itself.

In short: it was fun, but ultimately useless (as of right now). Having the functionality mapped out might prove to be useful later, but not yet.

So, it just occured to me that I haven’t updated on the status of the reprap in a while. Obviously, I didn’t finish the metal mendel, although my partner in crime is moving the project forward while he stays for summer school. I think the metal mendel will be finished by the time summer is over, too: we were at least halfway done, and now he has a bunch more time on his hands to put into the project.

Despite not finishing the metal mendel, I still want a reprap of some sort (there’s a reason I bought two sets of electronics), and I’ve opted for the recently developed mini-mendel. I got the RP parts, just ordered the motors and bearings, and am now waiting for more money so I can get the rest of the mechanical bits, plus extruder RP parts and bits, plus enough stuff to get my boards working again (they’re in pretty poor shape right now, I’m sorry to say). So, I have stuff, but I’m not quite ready to move forward. There’s also the small matter of stubborn de-soldering jobs I’ll have to do…

Basically, there is a very high probability that I will have a reprap by the end of the summer.

Hi. The MCM starts in 2 days.

I have to finish a paper and a bunch of lab questions before then, and I want to do at least one run through with my talk on maglev trains (as well as hacking S5 to auto-advance ala ignite), run at least one reprap part into existence, find if we can do etching cheaply, start the E/M test, and talk to a prof about what sort of equation I should use in a feedback loop.

Whew.

So with all of this to do, I took 3.5 hours off and coded up a framework for a problem posed by my prof that could have been a potential summer research topic: looking at the bottleneck assignment problem, what’s the relationship of n and the probability distribution used to assign weights to the assignments? If you are terribly lost, and I manage to do some work on this after the MCM, then I’ll post an update. Point is, I’m code deprived or something, and I just finished something I thought would take me at least a week, which shows me just how good my estimation abilities are (off).

And updating wordpress isn’t such a lark: I gotta do backups? Hell, gotta wrap this stuff up into a script

This is a very quick and easy hack to convert an LED light that runs off batteries to mains (wall) power.

Standard warning: following these instructions may kill/maim/turn into flowers everyone your know and hold dear. Be smart.

Usually, LED lights run off batteries, because… well, let’s expand the acronym. LED stands for light-emitting diode, a diode being a circuit element that usually only lets current through in one direction. Hence, it stands to reason that trying to put an alternating voltage across it will result in subpar performance, since half the time the current is trying to go “the wrong way”, and it won’t light up very brightly*. Also, making a diode rated for 120V is probably a pain: regular 1N4001’s rate to 50V.

However, batteries are a very poor power source for a stationary light. Since the light has to put out an appreciable amount of light for long period of time (versus, say, a flashlight), the batteries wear out quickly (and I don’t get why regular alkaline batteries are so prevalent. Rechargeable batteries have not been shown to be detrimental to the environment to me, and taking the position of the armchair environmentalist, it seems that even if you could squeeze only 10 charges out of it, it would displace 10 batteries otherwise destined for the landfill, and grabs energy from the wall at at least 80% efficiency (depending on your charger). The only problem I would see with this is running out of Li (unless we’re talking strictly NiMH), but we just need to get working fusion, and we could probably synth our own Li. Of course, this would be incredibly ‘inefficient’ as a process to produce Li). Hence, the motivation for this particular mod.

To get DC from the wall, the easiest solution is grabbing a wall-wart (essentially an AC->DC converter in a plug) and sticking it in place of the batteries. Find yourself a wall-wart that outputs about the same voltage as all the batteries combined; mine used 3 AA batteries, for a total of 4.5V, so I used this 5V wall-wart from BG Micro http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=12944 (or something like it).

So, most of these wall-warts output their DC voltage through some obtuse connector: in my case, I got ’lucky’ and got a barrel type connector, where the outside of the connector was ground (0V) and the inside at 5V. To get at the 5V, I used a mangled paper clip. Note that you could also snip the wire, strip it, and figure out which one is 5V with a meter.

Now for linking the DC power into the light: in this case, I had to snip some more of the paper clip to get it to fit into the battery slot, and add some aluminum foil to connect the negative terminal with ground. If you snipped the wire, you could solder the wire to the battery terminals, or otherwise manhandle the two to stay together.

[caption id=“attachment_100” align=“alignnone” width=“300” caption=“A modded plug, using electric tape to secure the foil.”][/caption]

If you have multiple battery slots like me, bridge it with wire, again soldering or manhandling it into place. I have not tried this yet, but sticking a resistor in place of a wire might lower the voltage across the LEDs, and make more apparent such things as a “half intensity” mode.

[caption id=“attachment_101” align=“alignnone” width=“400” caption=“Wires marked in red for visibility.”][/caption]

Put the plug into place:

[caption id=“attachment_102” align=“alignnone” width=“500” caption=“What it says.”][/caption]

Then, we cover everything up/partition with electrical tape to lessen chances of death by 5V:

[caption id=“attachment_103” align=“alignnone” width=“500” caption=“Electrical tape is pretty cool.”][/caption]

At this point, if the wart is plugged in, the light should turn on.

[caption id=“attachment_104” align=“alignnone” width=“400” caption=“Tape should be used to secure the plug.”][/caption]

Tada! If I have time/motivation, I may do a more DIY method for the same result.

Tangent: Future Electronics packs their stuff much more efficiently than Newark.

• There are non-directional LEDs, but they tend to be a bit more expensive than your run-of-the-mill polar LED.

Also, sorry about blurry pics: still learning to shoot well with SLR.