The ICTP wireless school rages on. On Wednesday we did the annual “long distance link” exercise from Muggia to the ICTP. This year was cold, but at least there was no snow this time. Two out of three groups made the link work, and one of them didn’t even use an external antenna!

Photos are up in the usual place.

It’s that time again: the 2010 ICTP school on wireless networking is rapidly approaching. I’m leaving in two days and won’t be back until the end of March!

This year we’re trying out the new curriculum that we’ve been developing over the last year. All of that will be available for free on WirelessU once the school is underway.

It really is astonishing how many things suddenly require attention when you’re about to leave the country for five weeks. Arrivederci, Seattle!

Now the real question: If I invite over some friends, and we make models in this world, can we click “print” and have the results come out of the Makerbot?

UPDATE: My mistake. The viewer you’re looking for is Meerkat. It lets you export all of your old juicy Second Life data, and re-import it into your new simulator. Virtual Sushi 2.0!

Why does all of the best HV stuff come from Russia anyway?

Well, it turns out that waiting for strapping lads is a silly strategy, especially when you have the able assistance of brilliant (and also quite strapping) ladies.

Rather than just hold this squirrelly hunk of steel and awesome above our heads, I installed some heavy eyelets and carabiners in the ceiling, and slipped some ratcheting straps around the lamp. With the incredibly generous help of Willow and Star, the beast was wrangled into place to mate with… the 30lb steel mounting plate.

Oh, didn’t I mention the plate? It has six 1/2″ x 4″ lag bolts that grip into a huge 16″ x 20″ timber on the ceiling. It only took about an hour of machining and wrestling with a ratchet (and round with a burly Italian) to get it in place. That plate isn’t coming down until the building comes down…

…which means that I can now do chin-ups on the awesomest work lamp in the universe. I mean really, does your Chinese luxo-lamp knockoff give you 300 Watts of cool white love with six degrees of freedom on a six foot swingarm?

Didn’t think so. Now, to illuminate Moar Science!

I find it interesting that it’s 2010 and the mainstream voice is still hung up on the definition of “hacker”. Do people really still think that hackers are a bunch of thieves, spammers, and vandals? When much of the rest of the world recognizes the value of ingenious engineering, and DIY hackery is becoming so obviously mainstream, I can’t help but think that the old “hackers are evildoers” saw is only still around to provide a vaguely controversial lede.

Still, these folks manage to paint a pretty good picture of what’s going on in their respective spaces. And Matt, as usual, keeps things on target with a barrage of crushing one-liners. Great job, guys!

Here is a vector drawing I made, based on a whiteboard sketch a bunch of us worked on last year. (PDF)

Here’s the little guy on a ruler intended for laser cutting. (PDF)

It uses a TL494 to switch a MOSFET very rapidly, dumping current into the primary coil of a TV flyback. The air rapidly heats up when the spark is on, and it cools quickly when switched off. This causes the air to vibrate, making sound just like a speaker.

I used a Hitachi flyback (about $10 on eBay) but any flyback with an open primary will work. You can use jumper clips for electrodes (as above), but they will melt eventually. Tungsten electrodes are much better. You can also use anything else that is conductive and will tolerate heat, such as chunks of pyrolytic carbon.

Here is Plasmana’s original schematic. Replacing the IRF540 with a bigger MOSFET (such as the FQA16N50) will let you dump more current at higher voltage across the flyback, making even bigger sparks. Adding a gate driver between the TL494 and the MOSFET would also likely help.

A good heat sink is critical to keep the MOSFET from melting. I used a large copper CPU cooler with an integrated fan.

Datasheets:

• TL494 PWM controller
• IRF540A MOSFET
• FQA16N50 MOSFET

I played my first video games on it. I remember my two favorite games were Henhouse and Ambulance. I even got an introduction to text-based adventure games with Adventure.

But twitch-games can only entertain you for a while. It wasn’t long before I started fooling with the BASIC interpreter to make my own sounds and graphics. My crowning achievement was a program that would tell you how many marbles were in a jar by estimating.

I remember when it dawned on me that since the storage device used regular audio tapes, it might be possible to copy them using another tape recorder (and it was!) Too bad I only knew one other person with a TI.

The only thing missing was a modem. In retrospect, it was probably all for the best that I didn’t have access to a modem for another few years.