> 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/sensor.md). # Simulation **Package:** `yams.motorcontrollers.simulation` A `Sensor` models a named hardware sensor whose fields are readable from robot code and, in simulation, visible in the WPILib **Glass** GUI. Every field delegates to a real hardware supplier on a physical robot. In simulation, Glass can override any field's value, and trigger-based overrides can inject specific readings at scripted moments during automated testing. Use [SensorConfig](/api-reference/java-reference/config/sensor-config.md) to build a `Sensor` declaratively. Direct construction is available when you need finer control over the underlying `SensorData` objects. ## Value resolution priority Each field's value is resolved in this order every loop iteration: 1. **Real robot**: always returns the live hardware supplier value immediately. 2. **Active trigger**: if any registered `addSimTrigger` condition returns `true`, the associated override value is written to Glass and returned. 3. **Glass value**: if no trigger fired, returns whatever Glass has set for the field (including the configured default). 4. **Supplier fallback**: if no Glass value is available, returns the hardware supplier value. ## Constructors ```java Sensor(String sensorName, List sensorFields) Sensor(SensorConfig cfg) ``` The `SensorConfig` overload is the preferred way to create sensors; see [SensorConfig](/api-reference/java-reference/config/sensor-config.md). | Parameter | Description | | -------------- | -------------------------------------------------------------------------- | | `sensorName` | Display name shown in the Glass simulation window under `Sensor[name]`. | | `sensorFields` | Fields to register. Each field must have a unique name within this sensor. | | `cfg` | A completed `SensorConfig` builder. | ## Field access methods | Method | Returns | Description | | --------------------------- | --------------------- | ---------------------------------------------------------------------------------------- | | `getField(String name)` | `SensorData` | Returns the named field. Throws `IllegalArgumentException` if the name does not exist. | | `getAsDouble(String name)` | `double` | Typed convenience accessor. Throws `IllegalStateException` if the field is not a double. | | `getAsInt(String name)` | `int` | Typed convenience accessor. Throws if not an int field. | | `getAsBoolean(String name)` | `boolean` | Typed convenience accessor. Throws if not a boolean field. | | `getAsLong(String name)` | `long` | Typed convenience accessor. Throws if not a long field. | | `getDevice()` | `Optional` | The underlying WPILib `SimDevice`. Empty on a real robot. | ## Simulation methods | Method | Description | | ---------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `addSimTrigger(String field, HALValue value, BooleanSupplier trigger)` | Registers a conditional override: whenever `trigger` returns `true`, the named field is set to `value` and Glass is updated. Use `SensorData.convert()` to produce a `HALValue` from a primitive. | ## SensorData `SensorData` (`yams.motorcontrollers.simulation.SensorData`) represents a single typed field inside a `Sensor`. You interact with `SensorData` directly when constructing sensors without `SensorConfig`, or when calling `addSimTrigger` on an individual field. ### Constructors ```java SensorData(String name, DoubleSupplier supplier, double defaultVal) SensorData(String name, IntSupplier supplier, int defaultVal) SensorData(String name, BooleanSupplier supplier, boolean defaultVal) SensorData(String name, LongSupplier supplier, long defaultVal) ``` ### Typed getters | Method | Returns | Notes | | ---------------- | -------------- | ------------------------------------------------ | | `getAsDouble()` | `double` | Throws `IllegalStateException` if type mismatch. | | `getAsInt()` | `int` | | | `getAsBoolean()` | `boolean` | | | `getAsLong()` | `long` | | | `getValue()` | `HALValue` | Raw value applying full priority logic. | | `getDefault()` | `HALValue` | The default value set at construction. | | `getName()` | `String` | Field name. | | `getType()` | `HALValueType` | `kDouble`, `kInt`, `kBoolean`, `kLong`. | ### Setters (simulation only) | Method | Description | | ------------------- | -------------------------------------- | | `set(double val)` | Directly writes to the Glass SimValue. | | `set(int val)` | | | `set(boolean val)` | | | `set(long val)` | | | `set(HALValue val)` | Raw HAL write. | ### Trigger Injection ```java void addSimTrigger(HALValue value, BooleanSupplier trigger) ``` Registers a conditional override on this field directly. Triggers are evaluated in registration order; the first active one wins. ### Static converters | Method | Description | | ---------------------------------------------- | ------------------------------------------- | | `SensorData.convert(double value)` | Wraps a primitive in a `HALValue`. | | `SensorData.convert(int value)` | | | `SensorData.convert(boolean value)` | | | `SensorData.convert(long value)` | | | `SensorData.convert(DoubleSupplier supplier)` | Wraps a supplier in a `Supplier`. | | `SensorData.convert(BooleanSupplier supplier)` | | ## Example ```java import yams.mechanisms.config.SensorConfig; import yams.motorcontrollers.simulation.Sensor; import yams.motorcontrollers.simulation.SensorData; import static edu.wpi.first.units.Units.Seconds; import edu.wpi.first.wpilibj.DigitalInput; // --- Preferred: build via SensorConfig --- DigitalInput beamBreak = new DigitalInput(3); SensorConfig cfg = new SensorConfig("Intake") .withField("BeamBreak", beamBreak::get, false) .withSimulatedValue("BeamBreak", Seconds.of(2), Seconds.of(4), true); Sensor sensor = cfg.getSensor(); // Read the value (real supplier on robot, Glass/trigger in sim) boolean isTriggered = sensor.getAsBoolean("BeamBreak"); // --- Direct trigger injection after construction --- sensor.addSimTrigger( "BeamBreak", SensorData.convert(true), () -> edu.wpi.first.wpilibj.DriverStation.isAutonomous() ); ``` {% hint style="info" %} `Sensor[name]` appears as a device group in the Glass simulation window. Each registered field shows as a widget that can be read or manually overridden. {% endhint %} {% hint style="warning" %} The typed `getAs*` methods throw `IllegalStateException` if the field was registered with a different type. Register a boolean field with a `BooleanSupplier`, and read it with `getAsBoolean`. {% endhint %} ## Related pages * [SensorConfig](/api-reference/java-reference/config/sensor-config.md) * [Sensor (C++)](/api-reference/c++-reference/sensor.md) * [Tutorial: Using YAMS Sensors](/api-reference/guides/using-yams-sensors.md)