Hey,
First some background:
I have been struggling with LED lights for 4 or 5 years (or maybe more...)
They usually fall in multiple of these categories:
unpractical / big / super expensive | (never bought)
awful color quality | (skin looks green/magenta, super hard to remove in post even with correct tint/WB)
too dim (the placement in my room is pretty bad so need multiple ones anyways but that’s fine)
flicker, flicker, flicker, I like to make nice videos and I like to be creative with my framerate and shutter angle
They just die very fast due to probably overheating?
What I plan to make:
Custom celling lights!
Decent quality (~95 Ra ~90 Re) light
High Brightness
Underdriven LEDs on a big heatsink (should increase the life massively)
RGB-whatever for casual party (and red to keep nightvision)
basically a overkill light I can enjoy and fix for many years to use both as a room light, recording light (well, from above at least) and other purposes
everything should be dimmable (more below).
What I have:
bunch of designs, tests
Basically got the heatsinks/frame figure out, as well as Decent Quality LEDs, basic idea of the software, what features I want, over-whatever protection, both software and automatic (like fuses, other things)
What I don’t have:
didn’t order many parts (more below)
a working LED driver ☹ (more below)
fan-less power-supply (I’ll deal with it last myself, don’t worry about it)
So basically
First thing I went for is well, googling, after hours of looking at sold out super expensive chips , I resorted to ask on random discords, everyone suggested PWM, but I feel like that would flicker pretty badly? (please tell me)
later someone suggested using lm2596 CC CV module like
THIS looking at this diagram from some weird website
LINK it shouldn’t flicker? It’s only 300mV at 48kHz (also I would use max 1A per module)
I already had one and bunch of 5W leds, so powered them up on nearly max (mistake), pointed my camera (120fps 8.6°) and didn’t find any flicker also made sure they can deliver 1A over long time while being pretty insulated (they got warm but not really hot)
So instead of using a trimmer to set the voltage and current, I set the voltage using trimmer and used a MCP 4461-103E/ST
MCP 4461-103E/ST digital potentiometer for current (ordered 8, needed 6 to power 1 light)
took me about 6.5h to write a working I2C code… oh well
so I pointed my camera at 5W LED and used I2C to change the potentiometer wiper position (because the potentiometer controls the current to the LED) and well, it flickers, badly
I repeated the experiment with unmodified lm2596 module, used pots to set the current lower and lower… the flicker appears, gets worse and worse. So I feel like lm2596 is dead path? Please let me know!
I’m pretty sure I can throw these chips away (put into “forever” parts bin) which well, my fault, didn’t test enough but kind of unfortunate ☹
But anyways, what options do I have? How do I dim a light without flicker, I feel like even at 1MHz there will be flicker (let’s say I rented phantom v2512 and shot video at 500k fps and 10° shutter speed, for whatever reason) isn’t there another way than PWM? Or am I just wrong?
For white leds (majority) I don’t really need “infinite” brightness levels, I’d say 10 is ok, but seamless would be even better. For RGB it’s a must because of mixing.
Also I would prefer something “easy”, I do not have 100’s of euros to just prototype and find out 99% does not work. My budget for the project was 200€ per light, but would end up at around 300€ (the drivers were 30-40ish euro I think)
The leds I wanna use are 23V 300mA (would limit to 225mA) cool white + warm white in 4x4 matrix so 32 LED dies but was thinking to put them in 2x pairs (I know one should not do this) (plus like 5 rgb ones in the middle…)
What options do I have?, Please help !
note: by flicker i mean anything from visible turning on-off to weird bands on the walls or similar. when i test with sunlight or battery and resistor, i do not get that