Nano with 12 VDC supply and 5 V output

Just a little question.

I am using a 12 Volt power supply for a Nano. (12 Volts is a must)
Also I want to power three peripherals at 5 Volts ( Two relays, and a PIR)

So, which would be best to power the relays and PIR?

Run them from the 5V pin on the Nano.
or
Use an LM7805 connected to the 12V supply.

Any suggestions.

I would opt for creating a separate 5 volt buss simply because of the relays and make sure you use decoupling capacitors as well as placing some flyback diodes across your relay coils. Really up to you buy I would not power relays off the nano.

Ron

Thanks Ron

You might get away with powering a Nano from 12 V to "Raw" or "Vin", though some people report clones having regulators which fail at that voltage.

If you want to power anything else requiring 5 V - apart from a couple of LEDs at no more than 20 mA - then it is a terrible idea. The regulator has almost no heatsink, will overheat and shut down - hopefully a reversible condition.

Get a switchmode "buck" converter to 5 V, use it to power the Nano via the "5V" pin and all the other components. Just forget the on-board regulator. :astonished:

Paul__B:
Get a switchmode "buck" converter to 5 V, use it to power the Nano via the "5V" pin and all the other components. Just forgetthe on-board regulator. :astonished:

+1