2D Components
SensorToolkit works in both 2D and 3D. Some of the sensors have a 2D specific version:
RaySensor2DRangeSensor2DTriggerSensor2DLOSSensor2DArcSensor2DSteeringSensor2D
The remaining sensors already work in either modes.
Most of the documentation and examples are focused on the 3D sensors. The 2D versions are practically identical with only minor differences here and there. The manual pages will point out where there are differences.