I am using an Arduino Uno (side question, should I be using a different Arduino?) to code LEDs for an art piece. I am using SK6812 WWA and I will never be using full brightness, and they will never all run at the same time. I plan to have a ring of LEDs on the side of the round frame that stay dimly illuminated , and using a sensor, when a human approaches (note I have no built this particular part yet), those will switch off or become very dim and then play my animation from the LEDs on the back of the piece. Again those will never be at full brightness either. I am using a 5v adapter currently and want to make sure this project will work without overheating or some other issue.
The ring around the inside of the frame looks like it will be about 60 SK6812 WWA LEDs. My piece with the most LEDs has 130 LEDs on the back. They are never all lit at the same time and won’t be at full brightness.
There's no way to recommend one Arduion board over another, anything will run the code and one or two strips.
And I hear you say not that many, not at full brightness, but there is no substitute for measuring your worst case current and then arranging that the installation power supply will be entirely capable of supplying that, plus a bit of extra for good measure and to make the power supply more of a loafing than a sweating little guy, like an extra 25 percent.
Obvsly, I hope, you will run the power directly to the strip(s) and not tap it off the UNO.
You might benefit from perusing this
the care and feeding are more or less the same for all smart LEDs.
It won't hurt. But it's totally valid to plan on, as you've said, using less than that in practice and only providing for what you know will be (or measured to be) the real current.
And get a new calculator. Where I am
190 * 60 / 1000
is 11.4. Did you already mean to use one colour only, or 1/3 brightness?
An 11.4 amp 5 volt supply may be bulky and spendy. And I'll say at least of Neopixels that they are hella bright - I use higher brightness, yes, but usually have a few whacks worth of neutral density filter in front of them.
If the really beefy supply is no problem go for it but I would bet many ppl plan and "get away" with something a fraction of the calculated maximum, for just the reasons that turn up in an exchange like this.
It coukd be an excuse to buy an inexpensive DMM ifn you haven't one yet, and learn how to use it. If you do too very much in this hobby sooner later you'll benefit from doing.
Omg sorry I meant multiply by 20 not 60 The screenshot says to use 20 unless you’re trying to guarantee a margin of safety for all situations. I will update that other comment on the thread.
I just think that because I don’t even want or need them at full brightness, I’m safe using the x20 calculation. Thoughts? Or should I be worried?
Sorry I’m brand new to LED coding and figuring out the power needs and your comment was a little confusing to me. At this point in my journey it’s best to have really straight forward answers Are you saying that the x20 calculation isn’t good to use? That if I use that I would likely start a fire?
No. You'll be fine with the 20 in the formula and a 4 Amp 5 volt power supply.
And if you aren't fine, you will know the probable cause - too many simultaneous or too high an intensity for those you do illuminate.
The symptom will be easy to spot: the strip will go dim or wonky or both, no good power supply will be damaged if you don't run it over-spec all day long.
I would guarantee it but that would tempt fate.
I just meant if 4 Amps turns out to be inadequate, just get the beefier supply. And have a nice spare unit for your next project or whatever.
It's your money, so you could just get a 12 A power supply and leave the power matter (except for the wire gauge!) in the rear view mirror.
I repeat my recommendation to get yourself an inexpensive DMM, there isn't an hour goes by in my lab where one of its functions isn't just the thing. There are threadsful of comments on just how cheap you can go; notes on particular makes and models and an outline of desired features.
If you have any future in the hobby, spend a bit more. I like my cheap meter, I'm not afraid to drop or lose it, and one of the features I didn't even want, a frequency counter, has proved to be worth whatever extra it cost.
For 190 LEDs Arduino UNO should have enough memory but it depends on what other calculations you are doing. If you use the FastLED library you have a command to automatically limit the current consumption of LEDs.
/// Set the maximum power to be used, given in volts and milliamps.
/// @param volts how many volts the leds are being driven at (usually 5)
/// @param milliamps the maximum milliamps of power draw you want
FastLED.setMaxPowerInVoltsAndMilliamps ( 5, 2600 );
The screenshot says to use 20 unless you’re trying to guarantee a margin of safety for all situations. I will update that other comment on the thread.
Are you saying that the x20 calculation isn’t good to use? That if I use that I would likely start a fire?