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The EtherTen combines an Uno-equivalent Arduino-compatible board and Wiznet-based Ethernet support, along with a microSD card slot and Power-over-Ethernet support. [Product page]
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Joined:Thu Sep 19, 2019 2:15 pm
I want to share an interesting information for you

Post by Celena » Thu Sep 19, 2019 2:16 pm


I'd like to build a project which is completely powered off PoE but I want to power 2 or more LED Matrix Displays. What is the maximum amount of current I can draw from the +5Volt pins on the Arduino? Is there another way with PoE to get more juice without using custom injectors?

Joined:Fri Sep 20, 2013 7:25 am

Re: I want to share an interesting information for you

Post by Brissieboy » Thu Sep 19, 2019 11:14 pm

You did not state which Arduino, so I will assume a Uno.
The on-board regulator has maximum current of 1Amp, so that is the absolute limit.
However there are other factors here:
- the limit will be reduced by the power required by the on-board circuitry, so about 900mAmps
- the regulator will almost certainly get hot depending on what input voltage you are using. The regulator has thermal limiting so will probably shut down due to its temperature.
- If you are powering via the USB port, the limit will depend on the limit of that port (usually about 500mAmps on a computer).
You also do not mention what type of LED matrix display you want to use. If it is the large P10 32x16 DMD then you could require up to around 3Amps per DMD depending on the maximum number of LEDs that could be ON in any active screen, but I would suggest a minimum of 4Amps for 2 DMDs.

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