I am using a dc-dc boost to take 12v up to 32v to power led strings.
It has a current limit adjustment to limit current which is needed for higher power leds, using a potentiometer. I have 3 amps going to the leds, so yeah it is very bright for an outdoor sunlight display. But I need to turn it down in the evening or if cloudy as it runs on a 12v battery and I just want it bright enough but no more to consume battery charge.
I have tried using a digital potentiometer in the past to control a power supply but it was not fine grained enough to adjust voltage for a battery charger. This was a while ago. I watched some videos, particularly GreatScott's which was using almost the same unit to control, and it required a "high voltage" digital pot. I checked the current pot, and its only a 300ohm unit.
I have a lot of pro mini's, like 100 of them...and I just bought 100 of the uln2003 that were like 3 cents each, and so I am thinking I could use them to create a digital pot, because using 6 of them would be 18 cents..
so it could select 14 * 14 * 14 or 2,700 different resistor values.
Trying to search for this kind of thing just gives you tons of what you don't want, I don't want to see how to use an arduino to control a digital pot chip, thanks for nothing google. Now using uln2003 might not work but maybe something similiar would work. I have found examples of using opto's and mosfets to switch in resistors, but I need dozens of them, so the uln2003 with 7 on a 3cent chip is attractive. if it can work.
Or the worse final alternative is to use a stepper motor to physical rotate the pot, I have a few of those cheap jy-whatever steppers.
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