How do you program robot components?¶

To program motors, sensors, joysticks and other components, you must first create an object. To create an object you need:

The class of the object
The package the class is in
The parameters needed to create the object
to assign the object to a variable inside the createObjects function in robot.py

import magicbot
import package

class MyRobot(magicbot.MagicRobot):

  def createObjects(self):
    # This creates an object of type Class and assigns it to self.object
    self.object = package.Class(param1, param2, ...)

For example, to create a motor you need to use the wpi_talonsrx.WPI_TalonSRX class in the ctre library:

import magicbot
import ctre

class MyRobot(magicbot.MagicRobot):

  def createObjects(self):
    # The TalonSRX class requires a device number. The device # of this motor is 0
   self.motor = ctre.wpi_talonsrx.WPI_talonSRX(0)

Information on component classes can be found in the documentation:

wpilib package (most of the classes you need are found here)
wpilib.drive package (Tank drive, arcade drive, mecanum drive, etc)
ctre package (Contains the TalonSRX class we need to program motors)

Here is the documentation for the TalonSRX class: http://robotpy.readthedocs.io/projects/ctre/en/latest/api.html#module-ctre.wpi_talonsrx

Notice the class name here:

In addition to telling you the class name, it also tells you the parameters it needs. In this case it only needs a device number. Some classes however have different options for parameters and addtional details if it isn’t obvious what the parameters are for. The PIDController class is one example: http://robotpy.readthedocs.io/projects/wpilib/en/latest/wpilib/PIDController.html

_images/pid_controller_documentation.png

Notice how the end of the parameter list in the class says args, **kwargs?

This basically means that there are different options for what you can put after the first 3 parameters Kp, Ki and Kd

_images/pid_controller_parameter_options.png

A description for each parameters can be found below that: