Linear Speed Control For DC Motor

The Linear Speed Control For DC Motor project centers around an Arduino Uno board that acts as the brain for managing a 12V DC motor. Because the Arduino's digital output pins cannot supply enough current or voltage directly to a 12V motor, an IRF540 power MOSFET is used as a high-speed electronic switch. The Arduino sends control signals to the gate of the MOSFET, allowing it to switch the motor current rapidly using Pulse Width Modulation (PWM). Users interact with the system via two switches: Pushbutton S1 handles the basic On/Off state, while switch S2 dictates the forward-reverse direction of the motor. The core feature of the system is its linear speed control; the longer the pushbutton S1 is pressed, the more the Arduino systematically increases the motor's speed over time. Additionally, an onboard LED, labeled LED1, serves as a visual speed indicator, changing its behavior or brightness in correlation with the motor's operational speed. Associated discrete components, such as resistors, are integrated into the circuit to ensure proper gate pulldown and stable signal transmission. Power is supplied to the setup via a dedicated 12V DC power supply connected through a power jack, safely separating the motor's power domain from the logic level components while maintaining a common ground.