Not sure if this is the right section to drop this in, so feel free to move if need be.
I'm a noob when it comes to Arduino's electrics and my days of knowledge in that field are way gone. So I'm looking for some solid advice.
The project entails the powering of an Arduino Uno R3 with 12 LED rings (WS2812 5050 RGB Ring) with 12 LEDs each.
It needs to run 24/7 for 3 days. Some say this can be done using a 9V 1000mAh battery.
Others tell me I should use my BTF-60-5 (220V to 5V/12A).
And then there's all the options of using Vin, the USB port or the barrel jack.
Any advice would be welcome. Any calculations to help me understand even more so!
144 RGB LEDs at 0.06A each (full bright and white) will need 8.64A at 5V.
That is ridiculous. I would stop listening to them. 24/7 for 3 days would take more like a car battery. The BTF-60-5 is the choice, here.
The Uno is not a power supply. If you power through the barrel jack or Vin, the 5V is provided by a on board 5V regulator. That regulator has little heat sinking and will not provide much current before it starts to overheat and shut down. Wire from the 5V regulated external supply (BTF-60-5) to the 5V pin on the Uno. That will bypass the weak 5V regulator.
Provide some bulk capacitance on the supply to the WS2812 rings to smooth the supply under transient conditions.
AC to 5V supply will be needed to run for 3 days.
As noted, WS2812B draws up to 60mA at full bright.
.06A * 144 = 8.64A, x 24 hrs x 3 = 622AH of battery capacity.
1000mAH = 1AH, divided by 8.64A = about 7 minutes of run time if the battery doesn't fail immediately.
So I hook the 5V output of the BTF-60-5 to the 5V pin on the Arduino?
Is that the one on the block where it says Power? I thought that was only for output.
I guess you mean the Vin one, right?
One clear problem with the UNO which is primarily designed to mount "shields", is the means to connect to the sockets. Simply sticking wires in them is clearly unreliable. The proper way is to insert pin headers into the sockets, and solder to the pin headers. It is far more difficult to dislodge a whole multi-pin header than an individual wire.
A Nano is vastly more practical - you can solder to it if the pin headers are not fitted, or plug it with headers (soldered of course :smiley-eek: ) into a "terminal adapter", or solder it to stripboard, protoboard or a custom PCB
And then the problem specifically with the UNO and Mega 2560 is that if the PC is connected to the USB port while you are powering it through the "5V" pin, it may feed a slightly higher voltage to the PC's USB system and cause it to shut down, so you need to disconnect the 5 V while connected to USB.
I repeat my "stock" explanation to this question every time. The "Vin" - or "Barrel jack" on a UNO - is nothing more than a legacy "novelty" from the times ten or twenty years ago when 5 V switchmode power supplies were not common as they now are. It allowed you to use unregulated 9 V "plug packs" (US: "Wall warts") which were the common supply for computer "phone" modems and ADSL boxes which contained heat-sinked 7805 regulators. But the regulator on a tiny Nano or even the UNO board has minimal heat-sinking and is only suitable for simple demonstrations of the basic board and a few LEDs.
So you can simply forget the on-board regulator and "Vin" and when you have a nice regulated supply of 5 V - generally from a switchmode "buck" regulator - you want to convey it to where it is actually required - the "5V" pin and your other modules. :smiley-lol: