Good afternoon fellow Forum-goers! I am currently working on a building a Bluetooth, usb powered mood lamp using a 12 led neopixel ring, an Arduino Uno Rev 3 kit, and a 3D printer to make the case and lamp itself. however, I've ran into a bit of a snag. in order to make the lamp, I will need all the pieces that will go inside together before I start working on it. I am having a bit of an issue powering the neopixel ring. from what I read, the Arduino board will cover as much as 1A of current, but the project calls for at least 3A to provide adequate coverage for the led ring. so I will need a power source that will provide at least 3A and 5V, but will work with a usb port for either a computer or a wall charger. any suggestions? also, anybody with experience with Neopixel rings? I wondered if using just on 12 led ring will suffice for a desk lamp, and am considering adopting another 16 led ring if at all possible.
12 * 60 = 720 mA. https://learn.adafruit.com/adafruit-neopixel-uberguide/power
This 2A power supply is enough. http://www.adafruit.com/products/276
I have used a 12 Neopixel ring before. This should be bright enough for a desk lamp.
Awesome! Thanks for the reply! So there's no way to make this something with an USB power option?
Lovell: So there's no way to make this something with an USB power option?
I suppose this depends you what sort of USB power supply you're using.
The 720mA figure Pauly gave is with all the LEDs on (white) with full brightness.
I think a USB device is supposed to request permission to use more the some limit (I'm remembering 500mA but I'm not sure). So technically your device shouldn't pull 720mA from a USB port but there are lots of 5V supplies which use USB connectors which can supply more than an Amp of current.
I'm not sure if an Arduino will be happy supplying 720mA from its 5V rail but if you could hook up a different connection between the USB 5V supply and the NeoPixels, it should work.
If what you said about there being a 1A limit is true, then powering the LEDs shouldn't be a problem.
I wouldn't use a USB connection from a computer to power this. You might blow the USB on the computer.
Pauly: I wouldn't use a USB connection from a computer to power this. You might blow the USB on the computer.
DuaneDegn: there are lots of 5V supplies which use USB connectors which can supply more than an Amp of current.
A powered USB hub would be a good idea while the program is being developed but when the project is deployed I was thinking of one of these