Code Introduction

This repository uses Java to program an FRC robot. Most code that we care about is under src/main/java/frc/robot and generally uses the WPILib framework to interact with elements on the robot.

Useful links

• Intro to VS Code
• Running commands in VS Code
• Building and deploying code to robot
• Viewing robot debug output
• Introduction to Git (or just talk to Justin)
• Command-based programming (this is how we use WPILib to organize each component of the robot)

High-level code description

• Main.java
  • Boiler-plate code for building project. Can be ignored.
• OI.java
  • Custom uses of the controller inputs
• Robot.java
  • Instantiates each mode, e.g., teleop and autonomous.
  • Sets up cameras for teleop
• RobotMap.java
  • Instantiates sensors/subsystems
  • Maps joystick controls
• commandGroups
  • Each code file in this directory contains sequences of commands to use during autonomous mode
• commands
  • Each code file in this directory specifies one "operation" of the robot, e.g., DriveWithJoystick.java, SpinCellIn.java
  • Commands use access to a subsystem (see below) to make the robot do things, as opposed to directly accessing a motor, which is part of a subsystem
• custom
  • Code "classes" made by our group that do special things we needed our robot to do that weren't in the WPILib code
    • E.g., Ramper.java limits the acceleration of a command sent to a motor
• subsystems
  • Each subsystem is a collection of hardware (e.g., motors) that does a thing as a unit, e.g., Belt.java or DriveSubsystem.java

FAQ

So how does the robot know what to do when I press a button on the remote control? Examples:

Belt

This one is a bit convoluted...

• belt subsystem is instantiated here after being imported here so it can be used in this Java file
• The "default command" for the belt subsystem is set here to be the ManualBelt command. Note that the oi object is passed in to ManualBelt
  • The oi object is instantiated here
  • The "default command" is what gets run if the subsystem is not otherwise being commanded
• ManualBelt declares what its primary functionality is in the execute function
  • It grabs from oi here (getManualBeltRotation)
  • getManualBeltRotation pulls data from the second joystick, raw axis 5 here (zoom stick)
  • The output from getManualBeltRotation is piped into the belt's function turnBelt on the same line
• The belt subsystem knows which motor to actuate in its turnBelt function because it is defined here

Color sensor

This one is much simpler...

• The color sensor toggle button is defined here
• We define what happens when we press that button here
  • ToggleSensor is a "command" that uses the spinner subsystem