Human presence detection is essential for safety, security, or other reasons. There are various software and hardware technologies and methods for detecting the presence of a human body in an area of interest (AOI). Among those techniques, Radar technology is one of the widely used techniques if the aim is to detect only the presence of a human. As we all know, radar is a system that uses radio waves for the detection of an object and to determine its distance, velocity, and angle. A radar system consists of a transmitter that transmits electromagnetic waves (generally microwave). The waves transmitted reflect off the object and return to the receiver, giving information about the object’s location and speed. The radar technology can also detect the unique signature of a human’s breathing pattern and heartbeat.
The mmWave (millimeter-wave) Radar sensors are very accurate. It is a contactless technology that operates in the spectrum between 30GHz and 300GHz. Due to the small wavelengths, it can provide sub-mm range accuracy and can penetrate certain materials such as plastic, drywall, clothing. Further, it is not affected by environmental conditions such as rain, fog, dust, and snow. Due to short wavelengths, this radar sensor provides high resolution, and the antenna required is relatively small.
DFRobot’s new 24GHz millimeter-wave radar sensor can sense human presence within the detection area. Moreover, it can even detect static or stationary humans, such as a sleeping person.
The DFRobot radar sensor’s wiki page shares information about the working of this sensor. Firstly, the sensor transmits FMCW(Frequency Modulated Continuous Wave) and CW radio waves to the sensing area. Secondly, the waves get reflected by all targets which are in moving, micro-moving, or weak moving state in the area. The waves are converted into electrical signals by the MMIC circuit in the sensor. These signals are then processed with the help of data algorithms.