A WHEELCHAIR which can be driven with switches, joysticks, a scanner or by the occupant using their voice has been developed by Edinburgh University. The "smart wheelchair" is for children and adults who cannot use conventionally-powered chairs. Built by the communication aids for language and learning centre, the chair's bumpers detect collisions and trigger a brake, or back it away from the obstacle. A "line follower" lets the chair follow reflective tape on the floor from room to room.