| 摘要 |
A detector (3) for supervising a movable object comprises a sensor (1) mounted to or close to the movable, supervised object. The sensor continuously senses its position in relation to a segment of a surface (5) on a stationary object located close to or on, respectively, the supervised movable object. It outputs a signal only when it has decided that the sensors has moved in relation to said segment to a position outside limits set in advance. The sensor can be an optical sensor including an optical sensor element (11) such as an image sensor. The image sensor can capture images of the surface (5) which are analysed. This reflecting surface can be the surface of a special reflecting part (7) that has a suitable design allowing that information about distance or position can be easily obtained. A power supply unit (23, 23') suitable for supplying power to the detector and other devices includes a solar cell (27), energy accumulators of at least two different kinds and an intelligent control of the charging of the energy accumulators using control rules including for example fuzzy logic. |
