Small POV device shows off some big features

We’ve already added the components needed to build [Rucalgary's] tiny POV device to our next parts order. The little device sets a new standard for tiny persistence of vision boards. Instead of relying on the user to find the best speed and timing for swinging the board around, [Rucalgary] used an accelerometer. This is the point at which we’d usually groan because of the cost of accelerometers. We’re still groaning but this time it’s for a different reason.

The accelerometer used here is a Freescale MMA7660. It’s an i2c device at a super low cost of less than $1.50. The reason we’re still groaning is that it comes in a DFN-10 package that is a bit harder to solder than SOIC, but if you’ve got patience and a good iron it can be done. An ATmega48 drives the device, with 8 LEDs and one button for input. On the back of the board there’s a holder for a CR2032 coin cell battery and a female SIL pin header for programming the device.

Check out the video demonstration embedded after the break. We love it that the message spells and aligns correct no matter which way the little board is waved.

[Thanks Paul]


  1. pr0cj0n says:

    This is awesome, I just could not belive what I’ve seen for a moment! Great job!

  2. Robot says:

    The accelerometer is a nice touch.

  3. arekieh says:

    Any practical applications for this other then being awesome?

    I want to make one anyways lol.

  4. addidis says:

    That is pretty impressive, Love how he is all excited about how complete and ready to be pilfered his sources are. I wonder if it sports an OS hardware logo. Id say it is worthy of it.

  5. MrX says:

    This is a really really nice build! Congratulations!

    One note though, I encourage you to practice your speech, it will be extremely useful in your future. Making more videos like this is one way to practice but having an interactive audience is way better. ;)

  6. The Cageybee says:

    Props. Nice build.
    Also, some nice fast right hand action there….;)

  7. Whatnot says:

    I hear people use DFN-10 chips upside down to make it manageable, like this:

  8. Whatnot says:

    It’s called ‘the dead bug method’ btw

  9. MrX says:

    @The Cageybee

    That just gave me an idea – what about building a VGA color pov display, like this one, to show your favorite p0rn while you wank?

  10. Olivier says:

    Nice project. With a hot plate, I guess it should be fairly easy to solder the components.

    @MrX: I see accidents cuming.

  11. Beautiful, I think using accelerometers for POV will become the new standard pretty quickly.

  12. Kiwisaft says:

    >Also, some nice fast right hand action there….;)
    >Posted at 10:46 am on Apr 26th, 2011 by The Cageybee

    lol, gonna make it display *fap*

  13. Dielectric says:

    Cypress put a demo like this on their PSoC3 starter kit:

    Of course it costs more, but it can do other stuff too.

  14. John says:

    We use a hotplate or a toaster oven for our MMA7660 breakout boards and it works really well. You want a temp-controlled hotplate, and set it at about 250. We have fiberglass plates on both sides of the hotplate so you don’t accidentally touch the heel of your hand against the plate while placing the chip. You can leave a little bead of solder on each pad with an iron, or use solder paste.
    Here’s our breakout board:

  15. Its pretty clever to use an accelerometer.
    How hard are I2C devices to use?

  16. anfegori91 says:

    This has been done years ago:

    It’s a FreeRTOS based Casio F91W emulator. (Clock Calendar)

  17. Drone says:

    Nice job. But HaD, c’mon – this has been sooo many times before! BTW I heard Dangerous Prototypes is developing a POV board with accelerometer. Is this the same project?

  18. Max says:

    @anfegori91, Drone: +10.

    My first thought was “this is old as dirt” too.

    I have no problem with the device, I have a problem with it being presented as anything else than ancient. And I can think of several progressively less kindly ways to say that.

  19. Texas Toast says:

    DFN is not hard to solder, just make sure you can access the traces that lead away from the IC with your iron. Simply with the solder down the trace to the IC – Make sure to use good flux. DFN devices can be done almost as easily as TSSOP devices.

  20. Rogan Dawes says:

    I had a theory of combining a PS3 Move controller and an addressable strip of LED’s (perhaps via a shift register) to make a fully controlled light saber, with PoV capabilities.

    Using the research on the PS3 Move controller previously shown on HaD (about a month or so ago), you have access to a 3 axis accelerometer, as well as additional movement sensors. The Move has a full colour LED, i.e. there are 3 pins available at the end of the controller to drive a shift register. And of course, it has a pretty capable STM32 microprocessor to do all the heavy lifting and calculation related to angles and acceleration and movement.

    I think that could be a very awesome repurposing of a PS3 Move controller, indeed!

  21. greg says:

    This would be awesome in a wheel, working at different rounds per minute!!

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