RGB+W, when W is a seperate electrical connection

I have some RGB+W strips where the White is not addressable/controllable via the Data pin, but rather it’s own pin. These are 24v strips.

For those curious, my “datasheet” on these strips is available here: http://jpelectron.com/sample/Electronics/LED%20strips/LED%20strip,%20TM1804%20at%20Costco%20details.txt

Could anyone suggest some way, via relay (I realize that would only be on/off) or mosfet, or PWM dimmer - which would to controlled via the PixelBlaze, to then control the White LEDs via their separate 24v circuit?

While I don’t have a specific circuit to recommend, I did want to mention that I’ve used the Mean Well HLG series of 24V LED drivers (get the AB suffix for dimming).

You can directly connect for a simple on/off control using digitalWrite(pin)

Also, a hack that popped into my mind was to hot glue a photocell against one of your RGB LEDs, and use that one LED as your dimming signal for the white channel! The “3-in-1” dimmer in that power supply means it accepts PWM, 0-10V analog, or variable resistance as a control signal (a photocell is a variable resistor whose resistance varies with the amount of light sensed). A little clever experimental level scaling in code means you might be able to dim the 24V white using the brightness of the 1 LED.

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