michel p nepa g manara r massini u201c design and performance of an integrated antenna for a 433 mhz car park monitoring system u201d proceedings of the 2012 ieee international symposium on antenna and propagation in order to use such an antenna which has a better efficiency compared to the typical ceramic antennas and therefore allows the transmission power to be reduced communications between the parking sensor and the detection control unit are performed at a frequency of 433 mhz fig6 and 7 are photographs of a working prototype of an energy autonomous device for detecting proximity according to the present disclosure it has small dimensions and can be easily installed in the middle of a parking space in the asphalt or above ground fig8 is a flow chart of an example of a sequence of operations that can be performed by the prototype shown in fig6 and 7 substantially the microprocessor of the device for detecting proximity implements a connection with a monitoring control unit turns on the analog detection section and performs a detection of the presence or absence of a vehicle thereon then it turns off all the components transmits the results of the detection to the monitoring control unit and sets to stand by waiting to perform a new detection the detection device provides for the use of a single ultrasonic sensor both for the transmission of the detection pulse and for.