Displaying tweets with a laser pointer and speakers

 

This year at Toorcamp, [Rich] will be showing off his laser-based vector display, capable of projecting tweets using only a laser pointer, a pair of mirrors, speakers, and an Arduino. Steady hand and curses from lack of an optical bench not included.

 

[Rich]‘s Instructable goes over the finer points of the build; a Python script runs on his computer fetching all recent tweets with a certain hashtag. These tweets are sent over to a ‘duino where a bit of code translates the text into a scrolling vector display. The code for the project is based on one of [Rich]‘s previous builds to draw shapes with the same speaker/laser setup.

In theory, using a pair of speakers to draw text on a wall isn’t much different from drawing pictures on an oscilloscope. Of course, [Rich] always has the option of turning his LaserTweet into an oscilloscope when Toorcamp is over.

Relevant videos after the break.


Comments

  1. Destate9 says:

    Way cool!!!

  2. Harvie.CZ says:

    I want to try this single mirror scaner:
    http://spt06.chez-alice.fr/00/scan2.htm
    Using 4 of these little bass speakers:
    http://www.dealextreme.com/p/3w-40mm-speaker-driver-unit-black-4-ohm-122521?item=6
    And drive it using Arduino just like the one above…

    I’ve also found few more interesting links with some experiences described:
    http://spt06.chez-alice.fr/00/scan1.htm
    http://spt06.chez-alice.fr/00/lasers.htm

  3. DarwinSurvivor says:

    This may sound like a stupid question, but why not just drive the speakers directly from the computer’s sound card? You could easily use left and right for your x and y and take the Arduino completely out of the picture.

    • Robot says:

      It’s not a dumb question at all. Most sound cards do not supply enough current to dive anything larger than headphone speakers.

    • Robot says:

      *drive

    • Hi there – I’m the project author.

      Yup – totally reasonable to drive the whole thing right from a computer with some basic electronics.

      However – I originally designed the project to operate as just running off the Arduino – so had a bunch of code (character sets / etc) already done on that side of things.

      I know some audio amps don’t deal with the not-so-musical signals needed to drive galvo-speakers (but know of at least one person doing it successfully).

      Would probably be prone to just use a darlington to keep things simple.

    • harviecz says:

      Also most of soundcards are not DC coupled… But this can be fixed by bypassing output capacitors. But when doing this you should be sure to not overload the soundcard as you can possibly drain more power than with capacitor… Most audio amplifiers get hot when you use them for amping DC… This is why you can’t just also bypass input and output capacitors of audio amp…

  4. dbear says:

    Looks like it needs a uv laser and a phosphor screen with some persistence to be really readable. I had trouble tracking what it was displaying. Might be easier in the dark. Cool hack though.

  5. Galane says:

    When is someone going to *finish* a LASER MAME system for playing the old vector scan arcade games on a big screen?

    There were a couple of attempts some years ago but neither one got to the stage of having a fully playable system with perspective correction.

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