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What frequeny is your pca9685 set at?Hey all I'm about to start my controller build(Ill star a thread as soon as the boards i had made get here)but i thought i would post this here so anyone could see it.
I purchased this light for my aquarium Phlizon-Dimmable-Decoration-Saltwater-Freshwater/dp/B074DRJK18/ref=sr_1_5?crid=1PWPDGSW7IQQ2 ( Freshwater at the moment) these are the long thin ones but they have the 16 inch ones as well and disassembled it to see what i would need to control it and low and behold after looking at the driver it uses 3.3 volt pwm to control dimming i also fed 3.3 volt dc into the control wire since they are just using a potentiometer and it works with straight dc as well i went up to 4.5 volts and no harm as far as i can tell.
I have hooked it up straight to the pca outputs and working great.
And it is immaculately constructed as far as wiring goes.
The 12 volt driver is being used for the fans.
The lights will also turn on and of with just the pwm signal they will turn on at 6% on my setup and they turn completely off below that.
u do seem to lose a tiny bit off brightness at the top end just going to 3.3 volt so i may look into trying it up to 5 volts after i find the data sheet on the drivers i have some level converters i may try to get it up a little
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Have you tried a different frequency?
Lowering the frequency may allow you to dim below 6 percent.
For an example:
At 1000hz the on time of the pulse at 6 percent is (1÷1000)×.06=.00006 or 60 microseconds.
At 200hz the on time at 6 percent is (1÷200)×.06=.0003 or 300 microseconds.
The led driver may be filtered or not a be able to "see" a short pulse of 60 microseconds but may be quick enough to see a frequency of 300 microseconds and may allow you to dim the light to a lower level.
This may be worth checking out.
