All the tutorials and videos I have seen with Arduino use the usb connection to supply the board with power.
However, I read the specifications for the Arduino Mega and it says that "If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable."
I just confirmed from multiple sources, online, that USB is 5v.
So is it safe to connect the Mega to sensors and run it off USB power?
Sorry that this is a simple question - I am new to Arduino.
You are a little confused on how the arduino board can be powered.
There are two main methods. One is using the USB regulated +5vdc power source directly to the arduino board. The second method is to use an external voltage source plugged into the external power connector. This external power connector is wired to a on-board +5vdc regulator that converts the 7-12 volt external voltage to a regulated +5vdc voltage to power the board. So that +7vdc or greater specification applies only to the external power connector voltage requirement, not the USB power which already is a regulated +5vdc source from your PC.
In both cases the board gets the regulated +5vdc required by the boards components.
ha
Oh I see - thanks a lot.