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Thread: DIY graphic / pixel Poi displayed from SD card (mortonkoph's code)

  1. #1
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    DIY graphic / pixel Poi displayed from SD card (mortonkoph's code)

    Has anyone updated mortonkopf's SD/POI code from WS2811 to APA102 output?

    If not is there something I should know?

    I use it on a current project and would like to see how the APA102s preform.



    Edit: -5 points for spelling Morton's last name wrong, apologies.
    Last edited by Paolo; 12-21-2015 at 02:26 AM.

  2. #2
    Senior Member mortonkopf's Avatar
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    @Paolo, the issue is the SPI sharing. APA102 leds and the SD card are both SPI, whereas the WS2811 were not. I decided to wait for SPI sharing improvements to be made by others as this type of work is not my strong point.

  3. #3
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    Perhaps preload the image into memory and then display.
    Or use SdFatLib which has software SPI implementation. It wouldn't be a good idea to have APA102's on the same bus as the SD card.

    If you fancy something adventerous the MK20 comes in higher pin count packages and most sport 2 SPIs

  4. #4
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    @Xenoamor, I wish I hand the chops to roll my own board.

    @mortonkopf, that makes sense and points to the problem/challenge with streaming images from an SD card to the APA102 strips. I'll just make due with your APA102 code and your BMP converter for now. Thank you for publishing your code.

  5. #5
    Senior Member mortonkopf's Avatar
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    @Paolo, happy to share code, most of it is from other people, as usual.

  6. #6
    mortonkopf your page that says ''pov from SD card(with code)'' doesn't seem to exist anymore..it loads from a browser with a title but no code can we get the full code for your project somewhere? If it's on github, where? I am trying to do POV with apa102 from an SD card and I have a teensy 3.2. Really all I was hoping to accomplish was to take the image converter from jhorowitz and save a bunch of text files with the image code and run them. This really doesn't seem like it should be too difficult for an experienced coder (which I am not)...
    I was able to implement what Paolo was content with, your poi sonic routine with RGB arrays... but I am not... whats the point if you can't store a bunch of images?
    Surely someone must have figured this out... I just can't actually find it anywhere. Po Ting doesnt actually provide his full code anywhere either (that I could find) but he also is loading straight up BMP images while I'm content loading txt files with hex values from the image converter from an SD card...if I could.
    I'm assuming one would want the text file saved to array and then displayed following by the next image doing the same thing then displaying... man, your POI SD code would go along way in figuring this out... I have the SD card up and running too.

  7. #7
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    Looks like the WaybackMachine has a copy.
    https://web.archive.org/web/20191204...p/?page_id=228

  8. #8
    Senior Member mortonkopf's Avatar
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    yes, I have had untold problems with Wordpress since their update to "blocks", and most of the pages will not now render properly. A major rewrite is needed. I will dig it out and post tomorrow as I think that the one linked above was for ws2811 rather than the apa102. This change was needed because of the refresh rate issue. But in principle its easy to change things out. Also, there was a need, I think to change the buffer size.

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