In the design, two PWM were output from the controller STM32F103C8T6 to drive a stepper motor adapter, PWM frequency was use to adjust the speed of motor. The high-power infrared tube was applied to detect the position of seedling tray and control the wheel stops, groove infrared tube was used to record the angle of the wheel turned. System included three operating states which were automatic alignment, manual adjustment, running. When the seedling tray on a conveyor belt was to the bottom line of the drum, the drum sowed the seeds to start and stop the drum when the seedling tray passed through. Results showed that the circuit could keep normal and stable work and the control system had high precision. |