GSM Module

Voltage Regulator (with Heat Sink): Ensures a stable output voltage, critical for protecting the board and connected peripherals from power surges or fluctuations
Capacitors and Resistors: Essential for filtering noise from the power supply, setting up bias points in the circuit, and other signal conditioning tasks
LED Indicator: Provides visual feedback, commonly used to indicate power status or operational status

Pin Headers
ANALOG PINS: Labeled as “A0, A1, A2, A3, A4,A5” these are analog input pins used for reading analog sensors
DIGITAL PINS: Labeled “0” to “13,” these are digital input/output pins used for interfacing with various digital sensors, actuators, and other digital devices
Power Supply Jack: For connecting an external power supply to power the board and its components
Reset Button (P1): Allows users to reset the board, restarting the microcontroller and reinitializing the program without needing to disconnect the power supply.

I/O Reference (IOREF): Provides a reference voltage for the microcontroller inputs and outputs
Serial Communication Pins (RXD, TXD): For serial data transmission and reception, used for programming the microcontroller and for communication with other serial devices
Power Pins (VCC, GND): To supply power to the microcontroller and other components.

GSM Module (SIM800L)
- Module Overview: Provides GSM (Global System for Mobile Communications) capabilities, enabling the board to send/receive SMS, make calls, and connect to the internet
- SIM Card Slot: For inserting a SIM card, necessary for connecting to a mobile network
- Antenna: Enhances the GSM module’s ability to send and receive signals, improving communication range and reliability.
OLED Display
- Function: Used to display text, graphical data, sensor readings, and other real-time information
- Connection: Likely connected via I2C or SPI interface, common protocols for communication between microcontrollers and displays.