Stm32f1 and stm32subeide programming example - ultrasonic distance sensor drive

Ultrasonic distance sensor drive

Ultrasonic ranging module HC-SR04 Provide 2cm-400cm Non contact measurement function , The ranging accuracy can reach 3mm. The module includes an ultrasonic transmitter 、 Receiver and control circuit .

HC-SR04 My work is very simple and direct . The module sends out 40 KHz Ultrasonic wave of , After being reflected by obstacles , Reflect back to module . By using the propagation time and the speed of sound , We can calculate the distance between the sensor and the obstacle .

HC-SR04 The sequence diagram of the work is as follows ：

Combined with the working sequence diagram , We can get HC-SR04 The driving steps are as follows ：

• Trig The pin remains high at least 10us
• The module will now send 8 Period 40 kHz The ultrasonic pulse train is used to detect whether there is pulse signal return
• If the signal returns , The module will output a high pulse , Its width will be proportional to the extent of the object .
• The distance can be calculated using the following formula ： distance = High pulse time * Speed (340m/s) / 2
• Calculate the formula in centimeters ： distance = us / 58
• Calculate the formula in inches ： distance = us / 148
• It is recommended to wait at least 60ms Then start the next round of operation .

1、 Ultrasonic distance sensor configuration

Development environment construction 、 System clock configuration 、 Debugging configuration and serial port configuration , Please refer to ：