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Thread: RGB controller

  1. #11
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    Default Re: RGB controller

    Thanks for all the great info. I played around with a couple of the different codes posted and found one that works...well sort of I'm using a Wemos D1 mini and the problem I'm having is that there isn't enough voltage to drive my LED driver. Seems like when the output is set to 100% the voltage on the pin is only .8v is there a way to bump this to 3.3 or even 5v. I know it's a pwm output but even at a 100% it seems low.

  2. #12
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    Default Re: RGB controller

    Quote Originally Posted by keaster View Post
    Thanks for all the great info. I played around with a couple of the different codes posted and found one that works...well sort of I'm using a Wemos D1 mini and the problem I'm having is that there isn't enough voltage to drive my LED driver. Seems like when the output is set to 100% the voltage on the pin is only .8v is there a way to bump this to 3.3 or even 5v. I know it's a pwm output but even at a 100% it seems low.
    Could you extend on what sort of driver you are using ?
    I am using FQP30N06L mosfets directly from the Wemos gpio without issue .

  3. #13
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    Default Re: RGB controller

    Lets get something cleared up first.


    • What are you testing: Pixel or Dumb RGB?
    • If dumb RGB you need to take the WeMos D1 outputs and add a non inverting current sink circuit between the WeMos outputs and the Dumb RGB string. There are RGB amplifiers (see link below) that you can purchase that will do this for you.
      • Dumb RGB uses a common V+ and a seperate V- for each output (RGB = three outputs). They are active LOW so "ON" is a low voltage (as close to zero as possible). Off means "Not Sinking current". The actual voltage measured at "Off" does not really matter.
      • Dimming dumb RGB nodes requires the use of PWM. Using an analog output (variable voltages on the outputs) does NOT work for DUMB RGB nodes.
      • All this means is that your measurement of 0.8 volts is pretty good. It would be better if it was lower (NOT HIGHER).


    RGB Amplifier: https://www.ebay.com/itm/Mini-Inline...50f1c68e764c4a


    2020 Full sized show reworked for the new location. Only adding (famous last words) 13 RBLs that I finally got converted to using pixels
    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show. Dim show (3000 pixels) had regular visits most nights.
    https://www.youtube.com/channel/UCyX...ttrsZNARkUce0Q

  4. #14
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    Default Re: RGB controller

    https://www.google.com/search?q=high...jMGAalq-j3vYbM

    This is the CCS I've been using with no problems in the past R1 is 100k R2 2.2k
    Attached Images Attached Images

  5. #15
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    Default Re: RGB controller

    Quote Originally Posted by keaster View Post
    https://www.google.com/search?q=high...jMGAalq-j3vYbM

    This is the CCS I've been using with no problems in the past R1 is 100k R2 2.2k
    Edited out suggestion .
    Last edited by angus40; 06-01-2020 at 06:26 AM.

  6. #16
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    Default Re: RGB controller

    Quote Originally Posted by keaster View Post
    Thanks for all the great info. I played around with a couple of the different codes posted and found one that works...well sort of I'm using a Wemos D1 mini and the problem I'm having is that there isn't enough voltage to drive my LED driver. Seems like when the output is set to 100% the voltage on the pin is only .8v is there a way to bump this to 3.3 or even 5v. I know it's a pwm output but even at a 100% it seems low.
    Hi, if you are receiving the E1.31 values of 0 to 255 and then using analogWrite() to get a PWM output on a GPIO, 0.8 volts would be about right.

    The output range on the ESP8266 is 0 to 1023 (10 bit unlike the 8 bit commonly used), a value of 255 is only 25% and 3.3V * 25% = 0.825V. The easiest way to fix this is to multiply the E1.31 value by 4.

    analogWrite( <E1.31_value> * 4)

    If that was the case and corrected as above, 0 to 255 should give a 0 to 3.3 voltage when measured with a voltmeter, there is no guarantee that this will drive your driver though.
    Last edited by Barnabybear; 06-01-2020 at 07:29 AM.

  7. #17
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    Default Re: RGB controller

    AnalogWrite only generates PWM on pins that are PWM capable. Not ALL pins are set up to support PWM.
    Different devices (ESP/Nano/Mega...) have different PWM ranges and the E1.31 data needs to be scaled to the device you are using.
    A voltmeter cannot reliably measure a voltage on a PWM line. You must use an oscilloscope or logic analyzer. PWM is a square Wave output usually running at greater than 100Khz.
    • DC setting on a voltmeter requires a constant or slowly changing voltage.
    • AC settings are tuned to 50hz/60hz sine waves.


    2020 Full sized show reworked for the new location. Only adding (famous last words) 13 RBLs that I finally got converted to using pixels
    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show. Dim show (3000 pixels) had regular visits most nights.
    https://www.youtube.com/channel/UCyX...ttrsZNARkUce0Q

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