Have you ever seen a handheld laser rangefinder?

Handheld laser rangefinder

The accuracy of laser rangefinder mainly depends on the calculation accuracy of the time between laser emission and reception. According to the adopted technology and application occasions, laser rangefinder can be divided into conventional laser rangefinder with an accuracy of about 1m (mainly used for outdoor sports, hunting, etc.) and high-precision laser rangefinder for surveying and mapping, land measurement, architecture, engineering applications, military and other occasions with high accuracy requirements.
Phase method rangefinder is a rangefinder that modulates the phase of the laser and obtains the distance by measuring the phase difference of the reflected laser. Due to the need to detect the phase of the reflected laser, the received signal needs to have strong strength. Considering the safety of human eyes, the telescope system like pulse laser rangefinder cannot be used, and the range is small. The typical range of ranging is 0.5mm to 150m. The general phase laser rangefinder uses 635nm (red vision) laser as the debugging object, which is also commonly known as infrared rangefinder, But in fact, the definition of laser is not defined by color. If the 635 nm laser rangefinder is used to directly irradiate the human eye, it will cause irreversible damage. Please use and protect it correctly.
Because the speed of ultrasonic propagation in the air is greatly affected by temperature, humidity and air pressure, the measurement error is large, and the propagation distance is short due to the long ultrasonic wavelength, so the measurement distance of general ultrasonic rangefinder is relatively short and the measurement accuracy is relatively low. However, due to the characteristics of sector propagation of ultrasonic wave, its detection range is larger than that of photoelectric rangefinder. It is widely used in safety protection, cable height measurement, obstacle detection and other fields in practical engineering.