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Thread: OctoWS2811 Library -- One strip with ledsPerStrip = 300??

  1. #1
    Junior Member VoltVisionFrenchy's Avatar
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    OctoWS2811 Library -- One strip with ledsPerStrip = 300??

    Hello!
    I am working on an application with a local high school art class where we are using 1reel of WS2811 @ 60pixels/m = 300pixels to light up a sculpture. We are using a Teensy3. I have the power supply and wiring all figured out, but on the software side of things is it possible to configure the OctoWS2811 library to use only 1 strip @ 300pixels? I understand that the Teensy3 has enough RAM for 1000pixels and I only need 300....but I would like them on one strip. I am very aware that my "framerate/refresh-rate" will drop, but I dont care. We will not be playing video, but instead we will program the pixels to do slow rainbow-type things and waterfall simulation effects.... a slower frame rate is fine for us.

    I have done a previous project here where we used a Sandevices e6804 to send data to 667pixels in a single chain of WS2801 pixels. The Sandevices firmware just keeps reducing the refresh rate as the string's pixel count goes up. I was hoping for the same arrangement here.

    Should I try to "hack" the OctoWS2811 library or perhaps use a different library? Thanks!
    -frenchy

    Bonus Question: What should the "CPU Speed" be set to when using the OctoWS2811 library? I didnt see any mention in the Library reference docs nor in the forum (yet).
    --
    Respectfully,
    Steve French
    President, Volt Vision
    www.voltvision.com

  2. #2
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    On paper, a Teensy 3.1 would have enough RAM to handle 300 LEDs per strip w/o any changes to code (you'd just use the first strip), but if you're only driving one strip a different library probably makes more sense. Alternately, you could leave the strip intact, but cut/punch a hole in the strip after the 150'th pixel to break the DIN/DOUT connection there (leaving 5V and GND intact), and run a single line from the DIN of the 151st pixel back to the teensy. Then your single 300-led strip would be addressable as two 150-LED strips with only a single extra wire to run.

  3. #3
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by VoltVisionFrenchy View Post
    I have the power supply and wiring all figured out, but on the software side of things is it possible to configure the OctoWS2811 library to use only 1 strip @ 300pixels?
    It is possible to configure OctoWS2811 for 8 strips of 300 and then connect only 1, leaving the other 7 outputs unused.

    On Teensy 3.0, this wasn't feasible because of the limited RAM. Teensy 3.1 has plenty of RAM.

    Bonus Question: What should the "CPU Speed" be set to when using the OctoWS2811 library? I didnt see any mention in the Library reference docs nor in the forum (yet).
    Either 48 or 96 MHz works fine. It really doesn't matter much.

  4. #4
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    You could also try using Fast SPI LED 2 (https://code.google.com/p/fastspi/downloads/list) which only uses one strip. You will need to inject power at multiple points along a 5m strip

  5. #5
    Senior Member Wozzy's Avatar
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    Quote Originally Posted by markvr View Post
    You could also try using Fast SPI LED 2
    FastSPI_LED2 is not yet working with the Teensy 3.1, however it works fine with Teensy 3.0.

  6. #6

    One single strip

    Quote Originally Posted by PaulStoffregen View Post
    It is possible to configure OctoWS2811 for 8 strips of 300 and then connect only 1, leaving the other 7 outputs unused.

    On Teensy 3.0, this wasn't feasible because of the limited RAM. Teensy 3.1 has plenty of RAM.



    Either 48 or 96 MHz works fine. It really doesn't matter much.

    I also looking in OctoWS2811 option for single strip 100 maybe 150 leds and possibilities to choosing pin for it.
    Octo working nice but all others like Adafruit or Fast etc. not working really well on T3.2. Implementation these libraries is a headache for me and affecting other processes in my project if I have to do something more than blinking couple of led. For example in my very complex code I use lots of things, sensors, oled, encoders, all analog inputs I need to use and lots of digital too in my Teensy 3.2.
    I need use just 24 led for visualisation movements and klicks encoders and so on.


    It will be nice if I can get Octo for things like that.
    I m pretty sure that exists hundreds of Teensy users with the same needs.
    Will be nice, great way if we can be able to setting 1to8 independent strips.

    Octo is really cool and easy to use and perfect fitted to Teensy. I tested it with small matrix, sigle strip too. But if I cannot easy get setting like independent strips or just one strip if needed, is useless for me at the moment because I didnít want build screen and display video and problem is that Octo occupies lots pins.

  7. #7
    Senior Member PaulStoffregen's Avatar
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    Wow, you found a 4 year old thread to post your question. Impressive, I suppose.

    Over the last 4 years, the FastSPI_LED library changed its name to FastLED. Teensy 3.2 has been very well supported for years. The old info on this thread is horribly out of data.

    Quote Originally Posted by Diodac View Post
    cannot easy get setting like independent strips or just one strip if needed
    Now there is a WS2812Serial library (since October 2017) which gives you non-blocking DMA-based transfer like OctoWS2811, but on a single pin. On Teensy 3.2 you can run 2 instances (on Serial1 & Serial2) at the same time, and if you overclock to 120 MHz a 3rd instance can run on Serial3.

    https://github.com/PaulStoffregen/WS2812Serial

  8. #8
    Quote Originally Posted by PaulStoffregen View Post
    Wow, you found a 4 year old thread to post your question. Impressive, I suppose.

    Over the last 4 years, the FastSPI_LED library changed its name to FastLED. Teensy 3.2 has been very well supported for years. The old info on this thread is horribly out of data.



    Now there is a WS2812Serial library (since October 2017) which gives you non-blocking DMA-based transfer like OctoWS2811, but on a single pin. On Teensy 3.2 you can run 2 instances (on Serial1 & Serial2) at the same time, and if you overclock to 120 MHz a 3rd instance can run on Serial3.

    https://github.com/PaulStoffregen/WS2812Serial
    Paul, not info but Iím out of data hahah
    Iím very new user these things like neopixel
    I know about them from years but I had not enough motivation to use them and had no time to digging topics. But now I got some ideas for implementation.
    Thank you for sharing link. But after my last post I got Octo on my bench and rewrite it to my needs now I got what I needed. I do some more testing and share it on GitHub and on our forum piece of useful examples.
    Hah it will be my first repository. Before I was too shy for sharing anything.

  9. #9
    Now I tested WS2812Serial and it working great 👍 any issues. Thanks Paul, you made my day!

  10. #10
    In Google is lot of links to outdated posts. Appears often firstly when searching. Google indexing robots working with huge delays and after last changes in Google, they pay more attention to listing commercial stuff first. Now is not easy positioning anything with Google if you even pay for it. But for that is good idea sometimes refreshing old posts and keeping whole website high by this. Because posts still exist in very first searching results and wouldnít go down.
    Moreover lots of people including me, pay more attention to content than date of post 😂

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