Buck Converter & Motor Speed Control Project
The motor will be powered by 5.3 volts that passes through L293D motor driver. The driver can then control the motor’s rotation direction – not used – and the rotation speed using a pwm signal provided by a microcontroller. The microcontroller we chose was a NodeMCU microcontroller which is powered by a ESP8266 module. The microcontroller has a 3.3 volts logic. The reason we chose it was to minimize the output voltage of the buck converter for it to work a smaller input voltage. We then found out that the for the motor to exceed the speed required, it will require a higher voltage, 5.3 volts. At this stage we could’ve used another microcontroller, but that wasn’t necessary as the current design works well. The microcontroller reads the signals from the photointerrupter, which also uses 3.3 volts to the output with microcontroller’s logic voltage. The microcontroller then calculate the signal’s frequency by measuring the signal’s high state length. The frequency read is then inputted into a PID controller alongside the desired speed – 400 Hz – and the various control constants. The PID controller then outputs a pwm signal which is sent to the motor driver to control the motor’s speed. The final control constants were Kp = 3 as the proportional controller constant, Ki = 4 as the integral controller constant, and Kd = 0 as the derivative controller constant.