I have a LED strip that takes 12v, and am wondering what the best means of powering both it and the arduino through a single wall outlet is.
I have a 12v 10amp power brick that should drive the whole thing (LEDs draw 8amp max, should in practice draw far less).
It currently works when I power the arduino via my USB outlet on my computer, and the LEDs via the power brick (connect both grounds so the data line on the LEDs will receive from the arduino).
So one idea is:
I power the LED strip in the same way that I currently do, but then I also supply 12v directly to the VIN pin? (and ground directly to a ground pin?) Would it really be that easy? Is the arduino somewhat isolated in this way from the power draw of the LED strip?
Another idea:
Same as before, but rather than putting the 12v into the VIN pin, I instead put it into a 12v->5v converter, then put that 5v into the arduino's 5v pin (and its corresponding ground to the arduino ground). Is this any better? And if I do this, do I have to still connect the 12v ground to the arduino ground? (technically they'd already be connected through the 12v->5v converter?)
It would be ideal if there were some way to just plug the 12v power brick directly into the arduino's barrel jack, and then drive the LEDs from one of the arduino pins (but the research I've done makes me think that's not going to happen- can't draw >1amp from VIN, and I don't know how else I'd do it...).
Are you controlling the LEDs with the Arduino? You didn't say anything about MOSFETs or anything...
I power the LED strip in the same way that I currently do, but then I also supply 12v directly to the VIN pin? (and ground directly to a ground pin?) Would it really be that easy?
Yes, it's that easy!
Sometimes if you are powering shields or other things through the Arduino's regulator the regulator can overheat if you drop too much voltage across it. But, if you are simply driving MOSFETs or NeoPixels, etc., you'll be fine.
Is the arduino somewhat isolated in this way from the power draw of the LED strip?
It's not isolated but there are separate current paths.
+12volt connected to the V-in pin could be ok, depending on which Arduino and what else is connected to it.
An easy/safe way is to power the Arduino (assuming Uno/Nano/Mega) with a 5volt phone charger, connected to the USB socket.
Leo..
Yes- I plan on using the arduino to control the LEDs. I'm not sure what a MOSFET is (or what it has to do with what I'm trying to do... I'm a bit of a newbie here!). I hope the rest of your advice still stands?
And regarding "using a phone charger"- the whole point is that there would be a single thing I have to plug into the outlet and I'd need no further setup. So that won't work.
The LED strip (WS2811) has 3 inputs: power, ground, and data.
I've had it working with the following configuration:
LED strip power to 12v power brick power
LED strip ground to 12v power brick ground
LED strip data to arduino pin 3
Arduino powered via laptop USB
Then also connect arduino ground pin to LED strip ground (I was told this was necessary for the data pin to function?)
I'm proposing:
LED strip power to 12v power brick power
LED strip ground to 12v power brick ground
LED strip data to arduino pin 3
Arduino VIN to 12v power brick power
Arduino ground to 12v power brick ground
An Uno is ok with 12volt on V-in.
Note that you can't draw more than 100mA total from any pin at that voltage.
Only the addressable LED strip connected is ok.
Leo..