Hackaday links: October 17, 2010

Cards you should crank

These greeting cards must be the product of a mechanical engineer run amok. They come with a crank and are designed to entertain with their simple, yet elegant movements. [Thanks Phil]

Magnetic card stripe reader

[JP] built an Arduino based magnetic card reader. It uses off-the-shelf parts but if you don’t mind buying the components this will get you up and running in no time. If you want more info there’s also this Teensy based version.

Homemade Airsoft sentry gun

This sentry gun has an amazingly fast firing rate that can continue for quite a while, thanks to the big flashlight housing that is holds a lot of ammo. [Thanks David]

Scanner easter egg

The engineers over at HP had a little fun building an easter egg into this scanner. If you know what you’re doing you can get it to play the Ode to Joy. It needs to join the old-hardware band from our Links post earlier in the month. [Thanks Googfan]


  1. someone says:

    I’ll be the one; the scanner is not a hack. It was made to do that.

  2. Dr.Evil says:

    The scanner one is also a very old “hack”.

  3. strider_mt2k says:

    OTS is cool if you can pull it off.

    It’s assembling the OTS stuff in interesting and provocative ways that can make it worth the money.

    Neat projects all!

  4. xorpunk says:

    All cool. The CC reader and cards that show mechanical and reverse engineering are the most intriguing.

    I’m glad you can’t clone debit and credit cards anymore(unless you can emulate the new security bank that is hard-encoded and not on any open-market cards).

  5. Lank says:

    This is cool, but old as hell. I knew about this in the 1990s.

  6. Hirudinea says:

    Those kenetic crank cards are neat, I think the yike-a-cycle card could be made into a record player card (very short play), and that would be much cooler than those stupid musical cards they have now.

  7. thetruthhertz says:

    In a world where benchmarks have decayed to the lowest common denominator… where shellacked dead puppies, vandalized rail cars, and crucifixes floating in jars of piss are considered “art,” my vote goes to the mechanical greeting cards.

    The idea is original, the artwork is beautiful, the mechanisms are ingenious, and watching them operate is sheer pleasure.

    I wonder what this guy could do with a pager motor and a lithium coin cell.

    Bravo, sir. I have your site bookmarked and expect to share it– a lot. I hope it goes viral.


  8. biozz says:

    clearly your a moron
    scanners were not meant to play ode to joy

    any one know how he built the airsoft gun?

  9. therian says:

    you fail, this one was made to play ode to joy

  10. Tom says:


    No, no this one was designed to play Ode to Joy

  11. taylorian says:

    sheez,,,if any of you would read…the scanner is not a hack…it is an easter egg….something that requires other than usual usage to reveal. it is included because of its similarity to hacks that do the same thing.

  12. biozz says:

    its a scanner … making it do anything else but scan is by definition a hack … if it was a scanner and ode to joy player than it would not be

    cracking eastereggs is still hacking even if its easy … grow up

  13. Pix3l the B1t says:

    Those cards are pure genius! All of that engineering in a tiny card :D especially the rotary engine, I could just sit for days watching it go :p
    The Airsoft sentry gun is awesome… and the portal turret noises make it even more so :). all somebody needs to do now is make the scanner play “Still Alive” :p

  14. chango says:

    @Pix3l: Not a scanner, but I’m sure it would sound just like this: http://www.youtube.com/watch?v=uKCX1CeXIjA

    • Pix3l the B1t says:

      Oh my god that is so epic! We have one of these at school (not the exact same one though); I’d laugh so hard if I got it to do that :p
      P.S. I think that I have a new hobby ^_^

  15. bobdole says:


    I have a mouse for my computer whose LED color changes when you press a button. Is that a hack? That’s what the button was designed to do, and when I press it, the color changes. Just because most mice don’t have that button, doesn’t mean that pressing it is “hacking”.

    Anyways, still an interesting video. I didn’t know these scanners had this easter egg.

  16. SOI Sentinel says:

    Wow, those cards are beautiful.

    @boizz: from the parts list, it looks like the airsoft gun is using a machined vortex block. They are feeding in compressed air or CO2 to fuel it. The air spins some BBs around until they happen to hit the exit to the brake line barrel, and out they fly. VERY air hungry. Not exactly consistent ROF but you’d never really notice since it has huge volume. The explosions are definitely happening because he’s getting jams in the barrel, which clogs and lets the pressure build up in his gun, and the lowest strength parts goes flying. Looks like the top to his hopper. Of course, this also sends BBs everywhere. Because it’s a constant air feed system, you also need the top to keep it from randomly sending BBs into the local area.

  17. chango says:

    @biozz Actually HP did publish documentation on how to play music with this scanner, including SCSI commands to play certain notes:


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