Hackaday Links: February 22, 2015

Hackaday Links Column Banner

We met up with Freescale guy [Witek] at our party in Munich last year, and he wrote in to tell us about the Freescale booth at Embedded World this week in Nuremberg. They’re going to have a bunch of Freedom boards to play around with and an extremely powerful RIoTboard with a 1GHz iMX6 Solo processor, 1GB of RAM, and 4GB of EMMC Flash. It’s not a Raspi or BeagleBone killer, but if you need a small Linux board with a lot of horsepower, there ‘ya go.

SmarterEveryDay is finally getting around to doing a series of videos about space. This guy knows his stuff, and with the access he can get, it should make for interesting viewing.

Here’s something for your Sunday listening: [Vint Cerf] at Carnegie Mellon talking about the Olive Project and the Interplanetary Internet. The Olive project is an archive for executables, and solves the problem of having to preserve hardware along with software. Cool stuff.

10 GHz pulse magnetron destroys electronics. That’s the only information you’re going to get with this one. There’s a fine line between ‘don’t try this at home’ and ‘this project needs replication’.

Most of the northern half of the United States is covered in a billion tons of snow. [Jamie]’s electric snowmobile/Power Wheels is the perfect vehicle for this occasion. It’s 36V with two 500W motors. Figure out how to replace the wheels with small treads, and there’s really something interesting here.

24 thoughts on “Hackaday Links: February 22, 2015

  1. I have a lot of wordy criticism regarding the sleek Web 2.0 revamps of (essentially) the worst abandonware sites from 1997, like Olive Project and the archive.org MS-DOS megadump. The summary is that there is a real community who gives two shits about “preservation” in a meaningful sense, but they aren’t these people, and the two don’t seem to cross paths for whatever reason.

  2. Wow, putting your hand directly in a 10GHz Microwave beam … I was going to say that the only thing more dangerous would be putting you head in the beam path but .. for these people it wouldn’t make any difference because they’re already fn{} dumb enough to put there hand in the beam. Darwinian really.

    1. It’s a PULSED magnetron. Peak power may be many KW. But the on time is so small that average power is just a few watts, and that’s what counts. It’s harmless for a few seconds as shown. A microwave oven magnetron is much more dangerous.

          1. From a VHF radio wave yes the danger would be a RF burn. That would take a lot of power or a very directional antenna though, most VHF radios only put out 100 watts or so.

          2. Heating and any other as yet not-well-understood effects. I know the difference between non-ionizing radiation (RF) and ionizing radiation (the scary kind), so cancer is not something I worry about. However, I understand exactly how good RF is at cooking flesh.

            @John: 100 watts into a highly focused directional antenna can easily create an ERP (effective radiated power) of many times the input power. DB is a logarithmic scale, and a good directional antenna can offer gain of 20 dB or more, easily. 100 times 100 watts is 10,000 watts ERP, or about 10 times more powerful than your average microwave oven. That same microwave oven can boil a cup of water in a minute. Imagine what it would do to your hand, your eyes, or worse, your brain.
            It’s a bit like frying an ant with a magnifying lens.

          3. @DainBramage: I think there’s some misleading mixing of concept/units in your example. If you have a 100W transmitter and a 20dB directional antenna, that means a target at some distance in the beam can receive *up to* 100x more energy compared to a setup with a non-directional antenna, where the vast majority of the energy misses the target. But it does NOT mean the target can receive 10,000W! (That would make free energy way too easy.) It can under no circumstances receive more than the full 100W, which is only 1/10th of the energy of a typical microwave oven. Much less dramatic, though I agree it’s still enough that it should not be treated casually.

            But the average power from a pulsed magnetron like this is probably only about 10W. The power absorbed by a hand in the beam, at the distance shown in the video, is probably 2-3W; as some misses the hand or is absorbed by the neon-filled vacuum tube. The setup is also powered only for a few seconds at a time. I would have no fears about putting my hand in it for those brief periods. However I wouldn’t expose my eyes or testicles at all, or leave my hand in it for minutes at a time. And would also be cautious about touching anything metallic like the pins on that tube, as they might concentrate energy to a pinpoint area of skin, resulting in RF burns.

          4. For me the primary problem is that the only research that has been done and concludes that low levels of RF energy are safe for the human body was conducted by mobile phone companies (as sponsors).

            It’s too much like when the tobacco companies told us that there was nothing wrong with tobacco.

            We know that even the radiation from a faulty TV (CRT type) can cause birth defects when pregnant mothers are exposed. We also know that keeping a mobile phone in you pants pocket (for a male) can reduce fertility.

            So while I am in no way able to disprove anything said by Chris C, I am still very much inclined to take DrainBramage’s view and err on the side of caution.

      1. Most people have seen it on the news. Many of us have seen it in our driveways. I’ve seen winters where the total accumulation was more than this, but I haven’t seen this much accumulation in such a short amount of time since 1978.
        Wheels are fine, if they have chains on them and being used to propel a snowblower.

    1. Display tube? Probably not as display tubes usually have phosphor. Neon wont do anything that far from electrodes up in that space anyway. I am guessing the red glow is coming from heat energy alone and not neon. Perhaps it’s a sensor of some sort? or emitter x-Ray?

    2. Its absolutely Neon gas lighting up in an electric field. The Dekatron has low pressure neon in it as the gas. At those distances needs a few volts to create the plasma and light the gas up. Any hi-voltage hi-frequency supply will generate enough power to light them up – his hand is acting as the earth return. If no hand then the water molecules in the air are adequate for the earth return. Check out plasma globes etc but be aware they have Neon as the carrier gas but have added Argon for the purple. My personal favourite is pale white Krypton but its not very bright.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.