Hardware Design of laser distance meter
The laser rangefinder consists of a main control board, a laser receiving board and a key board. The MCU of the main control board is HT32F52352, which is responsible for controlling the laser emission and reception, and calculates the distance between the rangefinder and the object. The laser receiving board is mainly responsible for the laser Receive and amplify the echo signal, and send the amplified signal back to the main control MCU
The main control board of the laser rangefinder can be divided into main control MCU circuit, power control circuit, acceleration sensor circuit, APD high-voltage bias circuit, oscillation signal coupling circuit, and laser modulation emission circuit according to its functions; the main control MCU circuit includes the above-mentioned HT32F52352 and peripheral basic circuits; the power control circuit includes USB power supply, battery charging management, chip power supply voltage regulation, etc., and power supply-related control; through the acceleration sensor circuit, the current attitude of the product can be obtained, and the angle can be calculated to perform more calculations in different modes , such as primary Pythagorean, secondary Pythagorean, vertical measurement, horizontal measurement, etc.; the APD high-voltage bias circuit is responsible for providing the voltage required for laser reception, and the sensitivity of laser echo reception can be adjusted by controlling the voltage; the oscillating signal coupling circuit is When the laser is emitted, a high-frequency signal is superimposed, and when the laser receives the echo, a frequency is used to couple with the echo signal, and the phase of the echo signal is obtained through the difference frequency phase measurement; the laser modulation circuit is used to adjust the laser emission. Power Control.
The laser rangefinder adopts the phase measurement method, so two laser transmitters (inner and outer optical paths) are used, and the echo signal of the laser is received by the same receiver, and the phase difference of the inner and outer two different laser signals can be calculated. The distance between the rangefinder and the object, when the distance between the rangefinder and the object is short, the phase difference between the inner and outer optical paths is small, on the contrary, if the object is far away, the phase difference between the inner and outer optical paths is smaller. will increase. The phase calculation needs to use the fast Fourier transform (FFT), and use multiple different frequencies to measure the test object at the same distance, and then the accurate distance can be obtained.
