Arduino DC Motor Speed Control using GSM

This system operates by bridging wireless telecommunication with hardware actuation using an Arduino Uno as the central processing unit. The SIM800L GSM module receives incoming SMS text messages sent from a mobile phone over cellular networks. Communication between the SIM800L and the Arduino is established using the SoftwareSerial library, allowing the microcontroller to parse the text content of the received messages. Depending on the specific commands received via SMS, the Arduino alters its output signals. To control the DC motor's velocity and rotational direction, the Arduino utilizes Pulse Width Modulation (PWM) and digital output pins connected to an L298N motor driver. Because the L298N and SIM800L require higher current and specific logic voltage levels, an external power supply provides robust operating current while a logic level shifter safely translates signal voltages between the 5V Arduino and lower-voltage components. Jumper wires on a breadboard tie the circuit together, ensuring that all devices share a common electrical ground for stable signal reference.