| 摘要 |
A detection system for a cat flap comprises a processor, a light generator and a light detector. Interposing of an animal body disrupts light travelling between the light generator and light detector. A light level value is determined and compared 42 by the processor to a reference value, such that when dirt reduces the light level value so that it falls below a reference value the user is alerted 44 that the system is dirty and should be cleaned. The reference value is calculated from previous light level readings. The processor determines 45 the deviation of the light level from an average of previous light level readings, and if the light level varies by more than an variation allowance then a signal 46 or action appropriate to the presence of a pet in the cat flap is sent or carried out, e.g. an RFID reader is activated to read a chip on the cat. |
