Power LEDs and Arduino from 5V, 10amp - use 5V or VIN?

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thecodingguy
 
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Power LEDs and Arduino from 5V, 10amp - use 5V or VIN?

Post by thecodingguy »

Hello,
I'm powering 3 of the 12mm LED pixel strand and a Arduino Uno 3 from the 5V, 10 amp power supply as a prototype for a standalone project. I am using the power supply to drive the Arduino by running a positive wire from the LED strands back to the 5V pin on the Arduino board and of course also a ground wire. This is what is recommended in the tutorial on the 12mm LED pixels, and it says to not use the VIN pin in the tutorial.

http://learn.adafruit.com/12mm-led-pixels/power

But then on the Arduino.cc website it says you can use the VIN pin to power the board ( from only from batteries? or can a power supply be used? ), which I have quoted at the bottom of this post.

So I'm confused as to why using 5V to power the board in the tutorial is recommended, while Vin is mentioned on the Arduino site. I want to do what is safest for the board, since the power supply is pushing 10 amps ( at only 5V, but still 10 amps! ). I did put a diode in between the wire and the 5V pin to make it a bit safer and maybe drop any minor voltage spikes from the power supply, but I'm still a bit worried about that 10amps. Can I get some information on the pros/cons of using 5V verse the Vin pin?
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.

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adafruit_support_rick
 
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Re: Power LEDs and Arduino from 5V, 10amp - use 5V or VIN?

Post by adafruit_support_rick »

You don't want to supply 5V to VIN, because of dropout in the Arduino's voltage regulator. VIN is the same as the barrel-jack power input, and Arduinos need at least 7V at VIN to operate properly.

5V is after the voltage regulator. Since you already have regulated 5V, that's the place to apply it.

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thecodingguy
 
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Re: Power LEDs and Arduino from 5V, 10amp - use 5V or VIN?

Post by thecodingguy »

Ok, thanks for clarifying that.

:)

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