Classic Nano Power Source

Hi I have a Nano (original flavor) and I need to power it with +5 VDC. I will not be using the USB connector however, so where would be the best spot on the Nano to "land" or connect the +5VDC to?

I intend to solder this +5VDC wire to the "5V" pin, knowing that this is actually intended as an output of the 5 volt regulator on the Nano. Are there any potential problems (concerning the Nano) with this?

This Nano is the controller for an outside temp/humidity sensor that communicates via an NRf24l102 board to another Nano inside. I have +12volts available outside, but I understand that +12 volt is a little too high for the Nano's onboard regulator. I am using the +12 Volt to supply an LM7805, and that is where i am getting the +5 VDC from.

Any constructive criticism is appreciated!

The only problem is this pin will power the ATmega328P (and USB chip) directly, without any sort of protection against voltage exceeding the chip's absolute maximum rating, or against reversed polarity. So it maybe requires a bit more care than when powering the board via the VIN pin, but other than that it's perfectly fine to do.

That sounds perfect. Make sure you have both the input and output side of LM7805 with capacitors such as 10uF. Since you're feeding it with a 12V supply, it'll help a lot to mount a heat sink on it.

or get a buck converter then you don’t need heat sink. In fact, with buck converter you can give it more than 5v and feed it to VIN, which is a dedicated pin for all that

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You also need high frequency bypass capacitors. Check the manufacturer's data sheet to see what is required. Not all are the same. Keep the leads as short as possible. For the high frequency bypass I typically solder SMD parts to the leads on the bottom of the board. These parts can save you an unbelievable amount of problems.

Thanks everyone! One of the devices that will use the +5 VDC is an nRF24l01 (which is supplied with 3.3 V from another regulator) board, so that is why I chose a linear regulator instead of a switching one. Thanks for all of the responses!!