All posts by Windell Oskay

About Windell Oskay

Co-founder of Evil Mad Scientist Laboratories.

Fixing a bad frequency fuse bit on an AVR

ATtiny2313

This is a quick note on AVR programming with the AVRISP MkII programmer, with which it is possible to foul up your clock fuse bits. =)

(This might be plain as day to some out there, but *I* didn’t know about it, so I thought I’d jot it down.)

Minor problem: I was programming some AVRs when I thought I might try to change the clock fuse bits to use one of the low-frequency internal oscillators. Apparently, it is possible to change the clock frequency low enough that the ISP interface can no longer program the flash– at which point it *seems* as though the chip is lost. These are inexpensive chips, (around $2 each), but the cost can add up quickly if you don’t fix the broken ones. Besides, they’re made of plastic, so you can’t even recycle them into a trivet.
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The Perfect Ammunition for Valentine’s Day

Valentine's day ammo 2

The holiday that we all collectively love to hate is sneaking up on us, which brings us right back to that all-important question: Exactly what type of projectiles should we be shooting at people? (Isn’t that what you think of when someone mentions Valentine’s day?) And yes, we’ve found the answer: Customized conversation heart ammunition.

Don’t have a decent catapult for the job? This is your perfect excuse to build one. You can make a Lego trebuchet (a leguchet), like we did, or take a peek at all the hot trebuchet action on Make this week and get creative.
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JellyBean versus the Digi-Key packaging materials

JellyBean versus the Digi-Key packaging materials

Digi-Key is a great place to order electronic components. Their online search is great, they ship quickly, and their prices are reasonable. If you have cats, there’s one more good reason to order from Digi-Key: They use interesting environmentally friendly packaging materials.

A day when a Digi-Key box arrives is a red letter day at our house. I get the components in the box, and the cats get everything else, and those are (apparently) some extremely exciting packaging materials. Typically there are layers of both white tissue paper and perforated brown kraft paper. Both types are krinkly– which cats are really into for some reason– but the brown perforated stuff is a particularly special treat. Our two cats will perfect their running leaps to pounce on it. They will fight over it, where the victor gets to roll around in it and get cozy inside– as JellyBean above has done.

Why? Well, I’m no feline psychologist, but I’ll take a few guesses as to why it’s so popular: (1) it’s easier to sink teeth and claws into than regular paper, (2) it’s more flexible, (3) it tears more easily, (4) if you’re hiding in it, you can still see out, (5) it’s very krinkly, and (6) it slides well on the hardwood floor.

All in all, it’s much better than a plain cardboard box, although they often get that too.

Two strange little facts

I often come interesting little factlets while browsing wikipedia, but here are two that really struck me as remarkable:

1. The super bowl is, in fact, named after the super ball. That confirms which of the two is actually more important.

2. Trans fats are not only incredibly dangerous to humans, but the are also largely to blame for the fact that whales have been hunted to near extinction!

Make a Computer Chip Trivet

Computer Chip Trivet: Deployed and Ready For Action!

You’ve just finished cooking something tasty on the stove and now you need a place to set it down on your dining table. You could reach for that old cast iron trivet, or a simple cork trivet, or the even the trendy silicone one.

But, if you really want to impress your geeky friends, this is the one to whip out.

Here is a genuinely useful kitchen tool that you can make: a trivet built out of old computer chips.
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Some hands on time with the iPhone

iPhone

As a popular technology blog headquartered in Silicon Valley, we were lucky enough to get a chance to try out the final shipping version of the iPhone this week.

If you think that it looks somewhat different from the pre-release versions of the iPhone that were shown off at MacWorld, you’re right: Unlike those, this isn’t a prototype; it’s a genuine released product from Apple.
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Gettin’ your due from TPC

Telephone

Last week I was lucky enough to be able to go to MacWorld and worship at the altar of the iPhone, as so many others have done. That is one heck of a nice looking device, and I really wanted to own one right up until I found out about the soul-crushing “service” contract that comes chained to it. And that’s one of the reasons that I want to remind you that it’s important– no it’s your fundamental duty— to be as ruthless and cruel to The Phone Company as they are to us.

I saw an interesting article this month in an engineering magazine called EDN. (Isn’t it interesting how engineering magazines have exactly the sort of names that you would expect engineers to come up with?) It’s about how to (legally) steal power from The Phone Company. Not that you can steal enough power to run your microwave oven (or even an LED, continuously), but it’s the principle that counts, right?

Telephone lines provide 48 V with some decent current, intended for such purposes as driving a solenoid to ring the (physical) bell of an old telephone, like mine above. By law, a device that isn’t actually communicating must present a resistance of at least 5 megaohms to that line, which means that you can only get out 48/5e6 = 10 microamps of current. The article shows how you could use this tiny trickle current to charge a supercapacitor (slowly) up to 2.5V, and then use that charged supercapitor to use an ultraefficient switching power supply to do… well… something. Like flash an LED once in a while.

Of course, this idea has been around for a while; some details about this source of power are even discussed in The Art of Electronics. But who is actually doing anything about it? I’m working on some other projects right now, so it’s not clear that I’ll be building something like this any time soon, but I hope someone is. It’s time that we all worked a little harder at gettin’ our due from TPC.

Floating bubbles on CO2

Bubble Wok

Today on Neatorama and Boing Boing, we saw a great demonstration video of a light aluminum foil boat floating on a layer of exotic heavy gas– sulfur hexafluoride.

You can actually do a version of this trick at home, using stuff that you either already have or can get a the grocery store: You can blow bubbles and float them– apparently in mid air– atop a layer of carbon dioxide; a not-very-exotic heavy gas. You’ll need a big pot, pan or storage bin (made of plastic or metal), some dry ice, and bubbles.

How do you do it? Place your dry ice in the pan and wait a few minutes for a layer of carbon dioxide to form in the bottom of the pan. (We used a 20″ diameter steel wok, which turns out to have a pretty good shape for the job.) Very, very gently, blow some bubbles above the pan and let them fall in. If your carbon dioxide layer is thick enough, the bubbles will bounce off of it, or often even come to rest, sitting in place.

We made a video so that you can get the idea, but you should really just try it yourself because it’s pretty straightforward and the pictures don’t do it justice.




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Duchamp redux

Fountain

Last week I visited the Exploratorium with some friends, and we saw this remarkable drinking fountain. The exhibit cleverly produces a little bit of introspective psychological trickery: It notes that the water is clean, and that the toilet has never been used, but asks why you might hesitate to drink from it? Funny how our brains work sometimes.

Drinking aside, the exhibit reminds me in particular of one other famous fountain.
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