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Thread: Teensy 3.2 flickering using fastLED library for some xmas lights projects

  1. #1
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    Teensy 3.2 flickering using fastLED library for some xmas lights projects

    Hi folks,

    I tried to use the Teensy 3.2 together with the OctoWS2811 Adaptor board for some Xmas lights projects using the fastLED library, but I got some nasty flickering. I loaded the code onto the Mega2560, no issues. Any idea folks?

    I am using just a little over 1000 12V LEDs WS2811, I applied 12V to three different points using a 2200 uf cap on each point: beginning, in between and at the end, using the same power supply. This is a 600 watts power supply(50A, 12V), this should be enough to power another 1000 LEDs.

    Of course, Teensy was powered up by 5 volts. Using 100 LEDs I see no issues.

    I played a little bit changing the freq, that did not help.

    Thanks a lot.

  2. #2
    Member crees's Avatar
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    Make sure the ground of the octows2811 is connected to the same ground as the pixels.

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    Is the flickering a constant thing, or just when updating pixels? Makes a difference on if the problem is code based or electrical. Simple test is to run test code that just does flat colours and swaps between them every 5 seconds or so.

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    Quote Originally Posted by GremlinWrangler View Post
    Is the flickering a constant thing, or just when updating pixels? Makes a difference on if the problem is code based or electrical. Simple test is to run test code that just does flat colours and swaps between them every 5 seconds or so.
    It looks like a constant issue to me, it drove me nut. I tested the code a couple times using the teensy, then I loaded it onto the Mega2560. Like I said, it runs beautifully on the Mega.

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    Quote Originally Posted by crees View Post
    Make sure the ground of the octows2811 is connected to the same ground as the pixels.
    I checked that, still I get the nasty flickering. Got to be related to Teensy because the same code runs beautifully on on the Mega2560.

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    As per the notice at the top of the forum, it helps to give more info for the stuff we can't see. We are giving you the basic things to check because you haven't shown the code (or a link if it's an example) or a schematic or (better) a photo of the wiring to allow us to do anything beyond guessing. Ideally enough information that somebody can recreate your problem on their bench.

    Flickering even when code is not trying to update the pixels has to be something electrical, so looking at voltages coming out of the Octo board is the next step. If you do not have a scope then running the blink sketch modded to point to the data pin you are using will allow use of a multimeter to confirm good voltages both at the output of the octoboard and at the din of the strip (measure from strip gnd to din).

    The being able to run 100 LEDs in interesting, since the only difference between the 100 LED operation and 1000 is the amount of memory, the time to complete an update and the load on the power supply. And your power supply setup should work if it's wired as described.

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    Member crees's Avatar
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    Also make sure your teensy is not being powered by the pc. Doing so can make it difficult to maintain proper signaling. I had this same issue and once the usb power was removed and the octo power was used instead the flickering went away.

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    Quote Originally Posted by itAlex View Post
    Hi folks,

    I tried to use the Teensy 3.2 together with the OctoWS2811 Adaptor board for some Xmas lights projects using the fastLED library, but I got some nasty flickering. I loaded the code onto the Mega2560, no issues. Any idea folks?

    I am using just a little over 1000 12V LEDs WS2811, I applied 12V to three different points using a 2200 uf cap on each point: beginning, in between and at the end, using the same power supply. This is a 600 watts power supply(50A, 12V), this should be enough to power another 1000 LEDs.

    Of course, Teensy was powered up by 5 volts. Using 100 LEDs I see no issues.

    I played a little bit changing the freq, that did not help.

    Thanks a lot.
    As I said before, if the code was loaded onto the Mega2560, worked fine. So I "prepare"(prepare means add a L7805 +5V regulator and a large cap so both the Teensy and LEDs can be powered by the same power supply) another OctoWS2811, problem solved! The only reason I am using the OctoWS2811 is because it has t he buffer built-in plus the resistors. The Teensy dont have lots of option regarding Expansion Boards. Sparkfun has one, that's it! The OctoWS2811 is the best I can find. I am not using the RJ-45 connectors. For simple projects, they are a pain you know where...
    Last edited by itAlex; 12-14-2017 at 05:30 AM.

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    Awesome you got it fixed. Thats what fixed an issue with a large matrix project. Sections were flickering and once we took the teensy off the USB power and powered the octo with 5v from the pixel power source flickering was gone!

    Quote Originally Posted by itAlex View Post
    The Teensy dont have lots of option regarding Expansion Boards. Sparkfun has one, that's it! The OctoWS2811 is the best I can find. I am not using the RJ-45 connectors. For simple projects, they are a pain you know where...
    Now there is another option....

    https://forum.pjrc.com/threads/48299...eceiver-by-CCR

    actually the Rj45 is a very good concept due to the nature of cat5/6 and allowing the TTL signals to maintain form over a decent distance from controller to first pixel. You will see in the youtube videos a receiver board option that allows easier connection to your pixels. Also has a place for large 1000uf cap so power ups are little less harsh on the pixels and provides some power buffer etc

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    Quote Originally Posted by crees View Post
    Awesome you got it fixed. Thats what fixed an issue with a large matrix project. Sections were flickering and once we took the teensy off the USB power and powered the octo with 5v from the pixel power source flickering was gone!



    Now there is another option....

    https://forum.pjrc.com/threads/48299...eceiver-by-CCR

    actually the Rj45 is a very good concept due to the nature of cat5/6 and allowing the TTL signals to maintain form over a decent distance from controller to first pixel. You will see in the youtube videos a receiver board option that allows easier connection to your pixels. Also has a place for large 1000uf cap so power ups are little less harsh on the pixels and provides some power buffer etc
    Yes, I got it fixed, I guess the issue was on the OctoWS2811. Interesting expansion board, where can I buy it?

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