2D Components
SensorToolkit works in both 2D and 3D. Some of the sensors have a 2D specific version:
RaySensor2D
RangeSensor2D
TriggerSensor2D
LOSSensor2D
ArcSensor2D
SteeringSensor2D
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.