Monitoring appts. for passenger area in public transport vehicle

摘要

The monitoring appts. includes an oscillator connected to an electrode which is partially led into the passenger area. The operating frequency of the oscillator is influenced by the surroundings due to feedback from the electrode. An evaluation circuit provides an empty message signal when the actual operating frequency of the oscillator matches a rest frequency determined when the vehicle is empty. When the oscillator frequency is different from the rest frequency, the evaluation device provides a signal indicating that the passenger area is not empty (i.e. occupied). The signals are processed and/or displayed by the vehicle computer. A compensation device determines the actual ambient conditions, esp. temp. and moisture, and sets the rest frequency accordingly.