To run devices like this from an external supply I'd recommend a little Buck regulator board such as the one Youmile does (https://www.amazon.co.uk/dp/B07TTH6C3J). You can then set the output to fixed 5V and drive the input from anything - USB 5V from a breadboard, a 9V PP3, 12V or 24V car, truck or boat battery etc. - with no worries about blowing anything in the Atom.