Power supply issues

I would like to use the following LED strip https://www.sparkfun.com/products/12027 with an arduino UNO, my goal is to have two 1 m LED strips controlled by the arduino. THe strips are 5v and each LED needs around 20 mA, since each strip has 60 LED it would be necessary to have 120 * 20 mA of current. Now I realize that the arduino UNO would burn out powering this so I was looking at the following 5VDC 3A power supply http://www.robotshop.com/en/5vdc-3a-wall-adapter-power-supply.html.

Ideally I would also want this power supply to also power the arduino, however I read that the uno need 9-12 v in and therefore this power supply would not work. Is there a way I can do this so it works on just the one power supply, or should I use the 5VDC 3A for the LEDs and have a battery for the arduino?

Ideally I would also want this power supply to also power the arduino, however I read that the uno need 9-12 v in and therefore this power supply would not work. Is there a way I can do this so it works on just the one power supply, or should I use the 5VDC 3A for the LEDs and have a battery for the arduino?

Use the external power supply for the LED strips and sacrifice a USB cable to supply the +5 at up to 500mA to the Arduino. That way one power supply will do it all.

Ray

so usb power is always 5v 500 mA?

sacredbandofthebes: so usb power is always 5v 500 mA?

USB power is always 5V and 500mA max (limited by host USB controller, for 1.1 and 2.0. USB 3+ has extended capabilities but may be manufacturer limited: http://en.m.wikipedia.org/wiki/USB

But, since you would NOT be using the USB PC hub but rather the main power supply, the current drawn could easily approach the maximum capability for the connector and circuit board traces- surely sufficient for the Arduino and perhaps even a piggyback shield.

Ray

sacredbandofthebes:
… or should I use the 5VDC 3A for the LEDs and have a battery for the Arduino?

Not a good idea at all! You don’t want to use batteries unless there is no mains power available.

mrburnette:
Use the external power supply for the LED strips and sacrifice a USB cable to supply the +5 at up to 500mA to the Arduino. That way one power supply will do it all.

I am puzzled as to why you would suggest the convoluted means of using a USB cable? What do you have against connecting the 5V supply to the Vcc terminal?

mrburnette: Use the external power supply for the LED strips and sacrifice a USB cable to supply the +5 at up to 500mA to the Arduino. That way one power supply will do it all.

I am puzzled as to why you would suggest the convoluted means of using a USB cable? What do you have against connecting the 5V supply to the Vcc terminal?

Just parroting the official word: http://arduino.cc/en/Main/arduinoBoardUno

5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

(However, I am guilty of doing this...)