Stage1b CTRE Solution by Daniel1464 · Pull Request #94 · frcsoftware/frcsoftware.org

Daniel1464 · 2026-07-16T21:18:42Z

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github-actions · 2026-07-16T21:19:58Z

🌐 Preview URL: https://pr-94.frcsoftware.pages.dev

Daniel1464 · 2026-07-17T02:25:55Z

This is marked as a draft for now as we're still waiting on alpha 7 to change extends Mechanism to implements Mechanism.

DylanB5402 · 2026-07-19T02:31:02Z

This is marked as a draft for now as we're still waiting on alpha 7 to change extends Mechanism to implements Mechanism.

Does this have to be a blocker? I'd rather merge this in early and go back to make code changes once alpha 7 is out

DylanB5402

I like this a lot, thank you for picking it up! Left a couple small comments, apologies if I'm jumping the gun on reviewing here

DylanB5402 · 2026-07-19T02:41:43Z

+  @Override
+  public void start() {
+    Scheduler.getDefault()
+        .schedule(robot.drivetrain.arcadeDrive(() -> 0.5, () -> 0.0).withTimeout(Seconds.of(4)));


Can we break this out into its own command in the Drive subsystem, like the turn in place one? I think it'd be good to use this as an example of how to compose commands for more complex behaviors (Ex: drive, turn, drive again)

DylanB5402 · 2026-07-19T02:42:53Z

+    robot.drivetrain.setDefaultCommand(
+        robot.drivetrain.arcadeDrive(() -> -xbox.getLeftY(), () -> xbox.getRightX()));
+
+    xbox.leftBumper().whileTrue(robot.intakeLauncher.intake()).whileTrue(robot.feeder.intake());


Might just be a commands v3, but I find having two whileTrue() calls in a row like that is a bit weird to read? commands v2 had the alongWith() helper, does v3 have anything similar we could use?

The commands v3 docs mention that you can chain whileTrue calls together, as well as running 2 commands in parallel inside of a parent command with awaitAll:

Command.noRequirements(coro -> { System.out.println("Hi!"); coro.awaitAll(command1, command2); })

In V3, you can also use alongWith like this:

robot.launcher.intake().alongWith(robot.feeder.intake()).withAutomaticName()

But IMO the withAutomaticName is a lot less intuitive, and I didn't mention alongWith since it does a very similar thing to awaitAll.

I kinda like awaitAll since it mirrors more typical async language feature (ex: Javascript's Promise.all). @zachwaffle4 as our resident commands v3 expert do you have opinions?

I would prefer to use awaitAll where appropriate, and I think it's more easily readable than chaining whileTrues.

zachwaffle4 · 2026-07-22T02:03:39Z

waiting on #108

# Conflicts: # copy.bara.sky

ArchdukeTim · 2026-08-26T03:34:35Z

+  private TalonFX leftLeader = new TalonFX(leftLeaderID, CANBus.systemcore(0)),
+      leftFollower = new TalonFX(1, CANBus.systemcore(0)),
+      rightLeader = new TalonFX(rightLeaderID, CANBus.systemcore(0)),
+      rightFollower = new TalonFX(3, CANBus.systemcore(0));


explicitly declare the types

Personally, I find this a lot cleaner (since theres less boilerplate) but I'm ok with changing it if everyone else wants to.

I think it's much more prone to errors, and readability is the same. Very little upside to doing it this way.

ArchdukeTim · 2026-08-26T03:35:15Z

+import org.wpilib.hardware.imu.OnboardIMU.MountOrientation;
+
+public class Drivetrain extends Mechanism {
+  private static final int leftLeaderID = 0, rightLeaderID = 2;


Why are these static

Because they're constants. I could make them UPPER_SNAKE_CASE but the stage 1A solution doesn't do that, so I didn't either

You could argue that all of the fields could/should be static here. I personally would remove it just so that when someone is looking at the solutions they don't feel like they made a mistake by not having a static variable

ArchdukeTim · 2026-08-26T03:42:43Z

+  public Command rotateInPlace(double angleDegrees, DoubleSupplier rotationThrottle) {
+    return run(coroutine -> {
+          double targetAngle = imu.getRotation2d().getDegrees() + angleDegrees;
+          while (imu.getRotation2d().getDegrees() < targetAngle) {


This will fail if targetAngle is outside of the bounds returned by getDegrees (-180-180).

ArchdukeTim · 2026-08-26T03:43:27Z

+        .named("Drive");
+  }
+
+  public Command rotateInPlace(double angleDegrees, DoubleSupplier rotationThrottle) {


I feel like this is a pretty bad example and not something anyone should write in real life

In real life, you're probably using a path following library so that isn't really relevant.
Furthermore, PID is going to be taught in stage 1C and not 1B.

Is there an example that could be used that would be useful on a real robot but simple enough to not need the later courses? If not should it just be removed without a replacement?

ArchdukeTim · 2026-08-26T03:44:46Z

+import org.wpilib.networktables.NetworkTableInstance;
+import org.wpilib.networktables.StructArrayPublisher;
+
+public class FuelSim {


Why is this class all static?

To make life easier for the student doing the exercise. Creating a new FuelSim() and passing it into every subsystem might get annoying.

Maybe all of the sims should be set up in Robot.java, and the sims are what gets passed into each subsystem, rather than them creating their own? Or FuelSim should be created in Robot.java with the subsystems passed in to it

The former might be possible, but the latter would force the simulation classes to be public which isn't great practice in general.

Changing FuelSim might have to be in a separate PR as well, since it's already merged in for the stage 1 templates and stage 1A solutions.

Yeah this being static is fine here

Daniel1464 added 2 commits July 16, 2026 17:11

initial commit

f23993f

Fix copy.bara.sky

ae2bdea

Move solution from ctre-commands to ctre-1b

b0d88b1

Merge branch 'frcsoftware:main' into stage1bCtreSolution

77f327c

DylanB5402 reviewed Jul 19, 2026

View reviewed changes

roboteer5291 added the Stage 1 label Jul 21, 2026

Merge branch 'main' into stage1bCtreSolution

e566fec

# Conflicts: # copy.bara.sky

github-actions Bot added stage1 examples infra Any infrastructure for building the website or syncing files labels Aug 22, 2026

Daniel1464 and others added 3 commits August 22, 2026 08:26

Merge branch 'main' into stage1bCtreSolution

817e2cc

Update solution to use FuelSim and move to correct directory

da8b9c1

Merge branch 'frcsoftware:main' into stage1bCtreSolution

d978469

ArchdukeTim suggested changes Aug 26, 2026

View reviewed changes

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zachwaffle4 commented Jul 22, 2026

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DylanB5402 commented Jul 19, 2026 •

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