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Hardware Hacking Christmas Cheer Music Toys Build Hardware

Homemade Robotic Xylophone Plays Holiday Melodies 70

compumike writes "Just in time to add a bit of geeky holiday cheer to your office, this video demonstrates how to build a robotic xylophone featuring handmade solenoids and aluminum bars, and shows it playing several classic holiday tunes. New songs can be programmed in with C macros, and this project could even be extended to perhaps play a melody when a new e-mail arrived or a software build has finished compiling!"
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Homemade Robotic Xylophone Plays Holiday Melodies

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  • Now we just need a printer than can play Fur Elise.
  • doesn't make patrick moore redundant.
  • The meat of exercise could have been summarised in about 3 sentences; I did not need to watch 13 minutes of video. Congrats, you have a GCSE / high school knowledge of electronics.

    • Re: (Score:3, Insightful)

      by Anonymous Coward

      You meanie. Knowing the theory is not the same as actually building it. The problems they solved with using re-pulser magnets at the bottom of the solenoids, hollowing out the striking bars for less mass etc are interesting. They show what happens when you try to build something like this in real life, as opposed to just sitting at home thinking you know it all already.

      • ...opposed to just sitting at home thinking you know it all already.

        Are you kidding? Just this morning I flew to Jupiter and back then rebuilt the engine in my car. But I didn't have to get my hands dirty or dump a lot of cash on rocket fuel.

    • Would have been much more interesting if they'd done it with a pair of robotic arms, rather than a bunch of homemade linear actuators...

  • Pedantic correction (Score:4, Informative)

    by residents_parking ( 1026556 ) on Monday December 06, 2010 @07:02AM (#34458322)
    That's a glockenspiel. A Xylophone has wooden bars. I know because as a kid I assumed it would be the other way round.
    • Xylophone [etymonline.com] -- from Greek xylon "wood" + phone "a sound".

  • Not a xylophone (Score:4, Informative)

    by diethelm ( 35652 ) on Monday December 06, 2010 @07:16AM (#34458360)

    A xylophone has wooden bars. This would more correctly be called a metallophone.

    With that important piece of information pointed out, you can all carry on now.

    • It could also be a marimba.

      Not sure what the difference between them is, other than a metallophone has metal keys by definition and a marimba’s keys are usually wood (but unlike the xylophone, don’t necessarily have to be).

      • by Anonymous Coward
        It could also be a marimba.

        Not sure what the difference between them is, other than a metallophone has metal keys by definition and a marimba's keys are usually wood (but unlike the xylophone, don't necessarily have to be).

        Not entirely true. A critical component of a marimba is the resonators under the bars. Those who are referring to this as a glockenspiel, or more generally as a metallophone, are 100% correct.

        -- A long-time percussionist
        • Marimbas (like xylophones) have the bars made out of wood (or a synthetic substitute). Marimbas have a lower range than xylophones. Both xylophones and marimbas in modern western form have resonator tubes. Given the range, this is probably best called a metallophone... if it were chromatic, then maybe it could be called a glockenspiel. - also a long time percussionist, especially wanting to note that marimbas have wood bars.
      • A marimba has resonator tubes suspended bellow the bars.

    • With a few modifications, it could sound much nicer than a toy piano. The plungers contact the bars too long. Examining a doorbell shows the plunger should overshoot the end of the electrical stroke to strike the bar and leave it free to resonate instead of remaining in contact to dampen the sound. Addition of either a cavity or tuned tube below the bar can give it the door bell or department store tone or a vibraphone with dampers in tuned tubes.

      Without either, it sounds like Schroder's piano on Peanuts

    • by Yvan256 ( 722131 )

      You know what else is made of wood?


      A WITCH!

  • They should write a few more tunes... it would easily supplant this project [slashdot.org] in geekiness.

    They have until February to design the robotic slide guitar and robotic congos. Cocktails not included...

  • featuring handmade solenoids and aluminum bars

    Nice handmade bar! I'll have two shots of transparent aluminum.

  • I hate when nerds don't know their stuff. Xylophones and Marimbas are made from wood. Orchestra Bells and Glockenspiels are metal. Also, striking the bar directly in the middle is what makes them sound so bad. The 'mallet' should be off center for the same reason the suspension bars are. Putting the hammers on the ends of the bars would improve the sound dramatically (theoretically).
  • by pz ( 113803 ) on Monday December 06, 2010 @10:56AM (#34459708) Journal

    I *loved* this project, even if it isn't brand-spanking new, and even if they got the xylo- / metallo- / whatever terminology not quite right. They got the physics right, even going back to original reports. Moreover, they didn't intone "4th degree differential equations" all-wide-eyed, but, instead with confidence that it's knowable and understandable. They not only machined their own bars, but wound their own solenoids on custom-machined forms! Holy western union, Batman! That's beyond nerdy: That's Thomas Edison / Alexander Graham Bell levels of intensity. Reminds me of MIT undergrads.

    And, beyond all that nerdfest of wonderfulness, they managed to make a very watchable and instructive video. To all of you who are bashing this impressive effort, I say: go do better, and then come back and sling your darts and arrows.

    They wound their own solenoids by hand! I can't get over that. My father, when he was working as an engineer, built a machine to wind coils because doing them by hand was so onerous. Doing it by hand, and showing how on a video, that's beyond showing off, that's showing *how*.

    My hat is off to these folks: well done!

    • by timbos ( 710908 )

      Reminds me of MIT undergrads.

      Heh. They are MIT grads... From: http://www.nerdkits.com/team/ [nerdkits.com] "We started NerdKits as MIT students "

    • They wound their solenoids by hand? Isn’t that a little like writing an application in assembly language? on a CPU you built from relays and piano wire?

      • by pz ( 113803 )

        They wound their solenoids by hand? Isn’t that a little like writing an application in assembly language? on a CPU you built from relays and piano wire?

        Yes, *exactly*. Now that I've been told they are in fact MIT graduates, it makes sense. The MIT EECS curriculum (which I had the tremendous fortune of being able to teach all four of the core courses) emphasizes precisely that: build your own from scratch so that you understand every single aspect. In the Intro to Digital Design course (6.004) students, do, in fact, build CPUs from relays and piano wire, as it were. Then they code in machine language for a while, followed by writing an assembler so they

        • In the Intro to Digital Design course (6.004) students, do, in fact, build CPUs from relays and piano wire, as it were.

          Pure luxury. In my college, we had to produce our own coke to smelt the copper ore to produce the wire and bits to make relays by hand, and THEN we got to program them in BINARY -- we didn't have a "machine language" until senior year.

          Unless these MIT folks are extruding their own wire, I'm not impressed.

  • The next step would be to add a simple MIDI interface - an optocoupler and a UART that runs 31,250 baud would work, IIRC. I build one in college (back in the early 80's). That baud rate is 1/64th of 2MHz, which was prescaled down by the Z-80 DART chip I used.

  • These guys have invented the electric pianola. Brilliant! But wait, this one is robotic!

    • That beautiful music you hear, is the sound of Skynet coming to get you. Unfortunately, music makes it hard to sneak up on a person, so I'm guessing it'll go for the deaf first.
  • Just one instrument? "J-Bot" has and entire band with horns, guitars, and drums all controlled by robots. http://www.capturedbyrobots.com/ [capturedbyrobots.com]
  • While I am a hobbyist in my own right, the tool set sophistication of this project is a bit high. Home cut and tuned aluminum bars? Give me a break, it would be less time consuming, easier and cheaper to run to "toys are us" and BUY a cheap xylophone. Seriously, lathe cut solenoid cases? OMG, who has a lathe? I would have gone to a hardware store, or sowing store to buy some plastic spools. Again, cheaper, easier, and less time consuming. MOSFETs are cool, but for the current and time constrains, a simple 2

    • Hohner Kids Glockenspiel, $19.99 on the web. Not having to find, cut, tune, and mount 8 aluminum bars, priceless.

  • Pat Metheny is touring now with a "robot band" on his Orchestrion tour. There are a couple videos on the web and a fairly good writeup on Wired: http://www.wired.co.uk/news/archive/2010-02/01/robot-band-backs-pat-metheny-on-orchestrion-tour

    Pat's website has more info about his reasons for this approach: http://www.patmetheny.com/orchestrioninfo/

    Not much tech weenie info, but pretty interesting for the musically minded.

"Well, it don't make the sun shine, but at least it don't deepen the shit." -- Straiter Empy, in _Riddley_Walker_ by Russell Hoban