> For the complete documentation index, see [llms.txt](https://yams.yassrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yams.yassrobotics.com/api-reference/java-reference/config/differential-mechanism-config.md).

# DifferentialMechanismConfig

**Package:** `yams.mechanisms.config`

`DifferentialMechanismConfig` configures a two-motor differential mechanism. Unlike the other config classes, the two motor controllers are supplied in the constructor and cannot be changed after construction.

All builder methods return the `DifferentialMechanismConfig` instance for chaining.

See also: [DifferentialMechanism](/api-reference/java-reference/mechanisms/differential-mechanism.md)

***

## Constructor

```java
DifferentialMechanismConfig(SmartMotorController leftSMC, SmartMotorController rightSMC)
```

| Parameter  | Type                   | Description                                                                        |
| ---------- | ---------------------- | ---------------------------------------------------------------------------------- |
| `leftSMC`  | `SmartMotorController` | The "left" motor. Its output mixes with the right motor to produce tilt and twist. |
| `rightSMC` | `SmartMotorController` | The "right" motor.                                                                 |

Both parameters are **required**.

***

## Builder Methods

| Method                                                        | Parameters                                                | Description                                                                    |
| ------------------------------------------------------------- | --------------------------------------------------------- | ------------------------------------------------------------------------------ |
| `withTiltStartingPosition(Angle angle)`                       | `angle`: starting tilt angle                              | Seeds the tilt encoder with an initial position. Optional.                     |
| `withTwistStartingPosition(Angle angle)`                      | `angle`: starting twist angle                             | Seeds the twist encoder with an initial position. Optional.                    |
| `withLength(Distance length)`                                 | `length`: arm length                                      | Sets the mechanism arm length for simulation. Optional.                        |
| `withMOI(Distance length, Mass mass)`                         | `length`: arm length, `mass`: arm mass                    | Computes moment of inertia for simulation. Optional.                           |
| `withTelemetry(String name, TelemetryVerbosity verbosity)`    | `name`: NT key prefix, `verbosity`: `LOW`/`MEDIUM`/`HIGH` | Enables NetworkTables telemetry for this mechanism. Optional.                  |
| `withSimColor(Color8Bit color)`                               | `color`: RGB color                                        | Sets the Mechanism2d visualization color. Optional.                            |
| `withMechanismPositionConfig(MechanismPositionConfig config)` | `config`: position config                                 | Configures the visualization plane and 3D offset for this mechanism. Optional. |

***

## Example

```java
SmartMotorController leftSMC = new SparkWrapper(
    new SparkMax(1, MotorType.kBrushless),
    DCMotor.getNEO(1),
    leftConfig
);
SmartMotorController rightSMC = new SparkWrapper(
    new SparkMax(2, MotorType.kBrushless),
    DCMotor.getNEO(1),
    rightConfig
);

DifferentialMechanismConfig config = new DifferentialMechanismConfig(leftSMC, rightSMC)
    .withLength(Inches.of(12))
    .withTelemetry("Wrist", TelemetryVerbosity.HIGH);
```

{% @github-files/github-code-block url="<https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/differential_mechanism/java/frc/robot/subsystems/DiffyMechSubsystem.java#L114-L121>" %}