Author Options:

Running Arduino and a phone off 1 usb port

I am planning to make a clock using an Arduino nano, with in-built USB port for charging. Can I use a 1A usb wall adaptor and run the arduino and charge a phone without running into problems?

4 Replies

Josehf Murchison (author)2013-09-26

Well the nano is 500ma max.

Phones are as much as 750ma and more.

So you are most likely over current at one amp.


Sorry for the late reply, I got my lcd and have been testing it! Could i possibly se 9v 1a and split it into 2 5v 500mah ports like most usb chargers are?

I would suggest a LM117 or LM317 H, E, or MDT adjustable voltage regulator set for 2.5 volts for each USB port.

The voltage regulator goes from 1.2 volts to 37 volts 500ma output and the adjust uses 50 ua bringing its total usage 1.1 amp when you push it by maxing it out.


Now that i think about it I can use the Arduino Vin pin and let it regulate its own voltage, then i could use a 5v 500mah regulator for the seperate USB port?