How to Control Servo Motor using Arduino

This project establishes closed-loop manual position control of an SG90 servo motor using an Arduino Uno and a 10k ohm potentiometer. The potentiometer functions as a voltage divider, connected across the 5V and ground rails, producing an analog voltage output at its wiper pin that varies between 0 and 5 volts depending on the physical rotation of its knob. This analog voltage is routed to one of the Arduino Uno's analog input pins, where the internal Analog-to-Digital Converter (ADC) translates the voltage level into a digital integer value ranging from 0 to 1023. Within the Arduino IDE software environment, the built-in Servo library maps this 10-bit ADC range proportionally to an angular range of 0 to 180 degrees. The Arduino then generates a pulse-width modulation (PWM) control signal—specifically a repeating square wave with variable pulse durations typically between 1 and 2 milliseconds—sent via a digital pin to the control wire of the SG90 servo motor. Inside the servo, internal circuitry compares the incoming PWM pulse width to the current physical position of its internal feedback potentiometer, driving a small DC motor through a geardrain until the desired shaft angle is achieved and maintained.