How do I supply either (1) dual voltage or (2) negative voltage?
You can make -5 V if you use an external power source, like in the circuit below (untested).

Connect the GND (-) from the Arduino to the +5V from the External (5V) source, than 0V will be the GND (with respect to the Arduino), but the GND of the external source will be -5V with respect to the Arduino.

I only used the resistors to get no short circuits, you can replace it by your own circuit (connecting the 5V arrow to Vcc and the -5V arrow to Vee).







simulate this circuit &ndash; Schematic created using CircuitLab