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Thread: Teensy 3.6 or Teensy 3.2

  1. #1
    Junior Member
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    Jun 2018
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    Teensy 3.6 or Teensy 3.2

    Hello,
    So i'm working on a POV globe project and I'm planning to use 180 LED's.
    I'm going to be using FastLED, and I read about people having great succes with teensies.
    So I'm looking into getting one, but I'm having trouble deciding what model.

    So my question is the following:
    Which Teensy has the faster speed for FastLED, Teensy 3.2 or 3.6?

  2. #2
    Senior Member
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    Your speed with fastLED will probably be driven by the LEDs, not the micro controller. For only 180 LEDs a Teensy 3.2+prop shield (since you will probably need level conversion) will do the job.

    The Teensy 3.6 would start to matter if:
    You are trying to procedurall generate your graphics and need floating point
    You want the onboard SD card to pull graphics from
    Your pattern needs more RAM than a teensy 3.2 has (unlikely but possible depending on how you code this). You can test for this by installing Teensyduino and doing a test compile and seeing how the usage numbers come out.

    Edit, hmm my first reaction is possibly wrong. If your code will be buffering the entire POV pattern in memory at 3 bytes per pixel 64kb split into 180 pixels will get a pattern less than 100 pixels wide. May be worth looking at how your code works and how it stores pixels before committing one way or another. Can certainly be done but would involve some form of colour compression and/or on the fly generation

    Edit to the edit: Also may be worth doing some math on if you can actually update your chosen 180 pixel strand fast enough to POV - you may find you need to split it in half and get clever writing twice to get your target time resolution.
    Last edited by GremlinWrangler; 06-14-2018 at 12:08 PM. Reason: Did the math

  3. #3
    Senior Member PaulStoffregen's Avatar
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    Nov 2012
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    I'd go with Teensy 3.6. The extra speed might end up making the whole project quite a bit easier (floats are about the same speed as integers), or it might be overkill, but it only costs about $10 extra. For a 180-LED POV project, that's probably a minor cost compared to the mechanical stuff.

    I'm sure you've heard of the internal LED PWM speed issues with WS2812. Usually I don't recommend APA102 due to the clock regeneration problems, but for POV they usually work much better. For 180 you'll probably have to go with 15 or 12 MHz clock speed.

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