I would like to know if it's possible to power the Arduino Due with 3.3 Volts. The spec sheet says to power it with 7 to 12 volts in order to properly use the 5 volt regulator, but I only need 3.3 Volts across my entire system. Also, if using 3.3 Volts for power is possible, how would I wire it?
Another question I have is how much current the Arduino Due consumes because I wish to use a battery to power it. I'm mostly just looking for a ballpark number (10mA? 100mA? 500mA?). For reference, I'm planning on using the 4 ADC pins and all the RX/TX lines.
Since no one else has replied, I'll try to help. In general, It is a bad idea to power the DUE directly from 3.3V. First of all you will be bypassing all the circuit protection that is built-in to the DUE. also the USB ports require 5V. And when you connect the USB port, there will be no circuit protection between the on board 3.3V regulator, and the 3.3V power supply that you're using. You will need to have a diode in line with your power supply/batteries. This would drop your voltage. you're better off to power it with a 9V battery. This would keep most of the power protection in place and alleviate any problems when connecting to the USB port.
as far as the current requirements goes, it would depend on what kind of sensors/circuits you had connected to it. I suggest getting your project completed for the most part and then testing the current to see what you are actually using. Then you can determine what kind of batteries you actually need.
I think only the 'programming' USB port requires 5V. The native port will work on 3.3v.
From memory, the basic Due board uses 120mA when just running a 'blink' sketch. This is relatively high for battery operations. If you don't need the Due features and you only have a coin cell or 2 AAA batteries, then you are much better off with one of the Nano or Mini Arduinos. If you do need those features then you may need your own custom board to strip off all the stuff on the Due board that consumes power.
Unfortunately, I need 3 UART lines (using multiple Bluetooth transmitters), so I'll plan to power the Due with a 7.4 Volt lithium ion battery for more umph and then use the on-board voltage 3.3 Volt regulator to communicate with my transmitters/sensors. I might make my own board in the future, but for now I'll use the Due.