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[Solved] Adjust Color Temperature Range on Daybetter 800 Lumens 120V 9W RGB+2700-6500K bulb

ctstinnette 603 5
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  • #1 20462188
    ctstinnette
    Level 2  
    OpenBeken is beautiful software. I was able to use CloudCutter to flash to 1.15.508 then OTA to 1.15.515. Everything is working as it should except for the color temperature slider doesn't match the limits of the hardware. The slider goes to 2000k but the bulb can only change to 2700k. Is there a means to calibrate this to the hardware's capability?
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  • Helpful post
    #2 20462312
    p.kaczmarek2
    Moderator Smart Home
    Hello, I am confident that the firmware by default covers entire possible range of temperature, there are no dead zones, it would make no sense IMHO, all PWMs are 0-100% range.

    Can you provide more details on the device you have? Is it using modified-I2C LED driver like SM2135, SM2235, etc? Or is it using PWMs? Is it using "alternate CW control" where one PWM is for brightness and second for temperature? As opposed to classic control when one PWM is for cool warm and second for white warm....

    Have you tried to set lower PWM frequency in flags? I am just guessing.

    Have you read about the gamma control system calibration?
    Quote:

    led_gamma_control () - led_gammaCtrl command handler, usage: led_gammaCtrl <sub-command> [parameter(s)]
    sub-commands:
    cal [f f f] - set RGB calibration values from color-picker or parameters
    gamma <f> - LED gamma correction, range 1.0-3.0: 1.0 = gamma off, default = 2.2
    brtMinRGB <f> - minimum brightness in % for RGB mode, range 0.0-10.0%, default = 0.1
    brtMinCW <f> - minimum brightness in % for CW mode, range 0.0-10.0%, default = 0.1
    list - list settings (and enable additional messages)
    Results will be displayed as Logs Info:CFG: messages (may want to turn off MAIN, MQTT and GEN to silence other messages)
    Any sub-command will enable channel messages containing output values in %

    Calibration sequence:
    1: clear current calibration values (= 1.0, default) by one of these methods:
    a: set color-picker to "white", i.e. #FFFFFF and enter command "led_gammaCtrl cal"
    b: or set values directly with command "led_gammaCtrl cal 1.0 1.0 1.0"
    2: adjust RGB LEDs to emit white light of preferred temperature and brightness
    3: enter command "led_gammaCtrl cal" - if successful the settings will be listed and stored in flash

    Use command "gamma <f>" to set gamma value. Range 1.0-3.0: 1.0 = gamma off, default is 2.2.
    To fully disable gamma correction you may also want to set brtMinX to 0.0.
    Use commands "brtMinRGB <f>" and "brtMinCW <f>" to set minimum brightness for RGB and CW LEDs.
    Valid range is 0.0-10.0% of full range (including brightness 0). "channel messages" is useful in finding suitable
    range: adjust brightness to desired minimum level and use the highest channel % value as brtMinX parameter.
    Channels 0-2 is RGB, channels 3-4 is CW
    Use command "list" to view gamma and calibration settings.

    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/led_gamma_control.md
    Helpful post? Buy me a coffee.
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  • #3 20462860
    ctstinnette
    Level 2  
    I have the bulb in this teardown - https://www.elektroda.com/rtvforum/topic3925050.html. As you suggested, it uses alternate CW control.

    I wasn't too clear in my issue description. I don't think there's an issue with the hardware or the color temperature control itself, rather just the label of the leftmost position of the slider, which should be 2700 instead of 2000. While it may seem trivial, it's important so that all the bulbs in the system display the same temperature when Home Assistant calls for 2700.
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  • #4 20465512
    ctstinnette
    Level 2  
    After more testing, I've determined that obk is capable of a lower color temperature than the Tuya firmware allows. Everything is working as it should.
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  • #5 20465513
    ctstinnette
    Level 2  
    I compared a bulb with Tuya to one with OBK. The OBK bulb is a lower temperature at its lowest setting, so my initial issue wasn't really an issue at all.
  • Helpful post
    #6 20465584
    p.kaczmarek2
    Moderator Smart Home
    One of the things to note for is the Current setting for so-called "I2C" LED drivers, but I am saying it just in case, your issue wasn't current setting, most likely.
    Just search for "Current" in commands list.
    https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/commands.md
    Helpful post? Buy me a coffee.
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