Arduino UNO R3 maximum current?

  • Hi.
    I am about to add some stuff to my gateway.
    It is an UNO with ethernet sheild powered through USB.

    I will add:
    Relay. measured around 80mA when relay is on.
    lightsensor. ?mA. read somewhere around 0,5mA but let's say atleast 3mA to be sure?

    Replace my cheap nrf radio against a 2.4G 22dBm 100mW NRF24L01P+PA+LNA from

    From icstation webpage:

    Maximum power:20dBm(about 100mW)
    Gbps:250k,1M,2M, Adjustable
    Emission current:95mA
    Sinks current:20mA

    I am planning to connect these directly to my uno on 3.3V pin and 5V pin.

    I don't know the consumption of the ethernetshield but i read somewhere around 150- 200mA

    Will this work? Will i overload my UNO?

    Any thoughts?

  • Hardware Contributor

    @xydix - Hello!
    About the uno:

    • DC Current per I/O Pin 20 mA
    • DC Current for 3.3V Pin 50 mA
      I think its 200mA total for all pins.

    You could use a transistor to drive the relay maybe?

  • 0_1485424008444_IMG_20170125_205415.jpg
    Not so fancy but this is how I did. It will do for now.
    This is the 5V pin under the USB connector.
    Now I get 5V directly from my USB power supply.

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