Potentiometer

Initializing the Potentiometer Class

A Potentiometer is created by using the following constructor:

Potentiometer(port)

This constructor uses one parameter:

Parameter	Description
port	The 3-Wire Port that the Potentiometer is connected to, whether it’s a port on the Brain, or a 3-Wire Expander.

A Brain or 3-Wire Expander must be created first before they can be used to create an object with the Potentiometer Class constructor.

# Create the Brain.
brain = Brain()
# Construct a Potentiometer "pot" with the Potentiometer class.
pot = Potentiometer(brain.three_wire_port.a)

This pot object will be used in all subsequent examples throughout this API documentation when referring to Potentiometer class methods.

Class Methods

angle()

The angle(units) method returns the angle measured by the Potentiometer.

Parameters	Description
units	Optional. A valid RotationUnits type or PERCENT. The default is DEGREES.

Returns: The angle measured by the potentiometer

# Print the current angle of the Potentiometer to the
# Brain's screen.
brain.screen.print(pot.angle())

changed()

The changed(callback, arg) method registers a callback function for when the value measured by the Potentiometer changes.

Parameters	Description
callback	The callback function to be called when the value measured by the potentiometer changes.
arg	Optional. A tuple of arguments to pass to the callback function.

Returns: None.

# Define a function potentiometer_changed().
def potentiometer_changed():
    # The Brain will print that the Potentiometer value changed
    # on the Brain's screen.
    brain.screen.print("potentiometer changed")

# Run potentiometer_changed when the value measured by 
# the Potentiometer changes.
pot.changed(potentiometer_changed)