Piezoelectric measuring device by pwm for a motor vehicle

A device for measuring a parameter for a motor vehicle, said device comprising a main module and a remote module, said main module comprising a control stage and a main piezoelectric transceiver configured to transmit an ultrasonic supply signal, said control stage being configured to electrically power said main piezoelectric transceiver and to command the transmission of an ultrasonic supply signal by said main piezoelectric transceiver, said remote module comprising a remote piezoelectric transceiver configured to receive the ultrasonic supply signal transmitted by the main piezoelectric transceiver, a sensitive element configured to measure said parameter and generate a measurement signal comprising at least one value of said parameter, and a measurement stage, connected on the one hand to the remote piezoelectric transceiver and on the other hand to said sensitive element and being configured to collect and store the energy of the ultrasonic supply signal received by the remote piezoelectric transceiver, to electrically power the sensitive element using said stored energy, to receive the measurement signal generated by the sensitive element, to extract from said received measurement signal the at least one value of the measured parameter, to generate a pulse-width modulation signal the duty cycle of which is representative of the at least one value of the extracted measured parameter, the remote piezoelectric transceiver being configured to convert the received pulse-width modulation signal into an ultrasonic measurement signal and to transmit said ultrasonic measurement signal to the main piezoelectric transceiver, the control stage being configured to determine the duty cycle of the ultrasonic measurement signal received by the main piezoelectric transceiver, the duty cycle of which is identical to the duty cycle of the pulse-width modulation signal in order to determine the at least one value of the measured parameter.