NZ596181A - An automatic parking disc for sensing whether a vehicle is parked or driving with the use of a multi-axis accelerometer - Google Patents

Abstract

596181 Disclosed is an automatic parking disc having a front face for being viewed from the outside of a land vehicle and a back face for being viewed from the inside of the land vehicle. The automatic parking disc includes a processor (136), an accelerometer (130) coupled to the processor to provide a signal, a chronometer to provide a reference time to the processor (136), and an autonomous power source (142) to provide the automatic parking disc with electrical power. The processor (136) is configured for determining changes between states of a land vehicle from parked to driving and from driving to parked and sample the signal provided by the accelerometer (130). The signal has a signal parameter representing the driving motions of the land vehicle. The processor (136) filters the sampled signal to suppress the signal outside a frequency window, integrates the filtered signal over a time interval in order to provide an integrated signal parameter. A change is determined from parked to driving if the present state is parked and if the integrated signal parameter is greater than an upper threshold. Alternatively, a change is determined from driving to parked if the present state is driving and if the integrated signal parameter is smaller than a lower threshold. The accelerometer (130) is a multi-axis accelerometer measuring velocity changes in a plurality of directions simultaneously.