I. Core Differences: Roles and Functions

Arduino microcontroller:Logic control, calculation, and input/output management. Executes the main program, reads sensor data, and drives actuators such as motors and LEDs.

Wi-Fi modules Communication coprocessor:Network connectivity and data transmission. Specifically responsible for connecting to WiFi networks, conducting TCP/IP communication, and sending and receiving network data packets.

II. Internal Connections: Collaboration and Dependence

Despite their different roles, they are closely linked and together form the core of IoT projects.

1. Hardware Connectivity

WiFi modules typically exist as peripheral modules of Arduino. They are connected through specific interfaces, most commonly:

Serial Port: For example, Arduino's Uno uses a software serial port or hardware serial port to connect to the ESP-01 module.

SPI/12C: Some more advanced WiFi expansion boards use these bus protocols for faster communication speeds.

Exception: Integrated Solutions. Many boards now (such as Arduino MKR1010, ESP32) integrate the functions of the Arduino (microcontroller) and the WiFi module onto the same chip or circuit board. In this case, the physical concept of a "module" is weakened, but logically, the microcontroller core and the WiFi RF section still cooperate within the chip.

2. Software Collaboration Relationship

In the code, this collaboration relationship manifests as follows:

2. 1Arduino (Brain) Decision-Making: The Arduino program determines the need for network operation based on logic.
2. 2Calling Dedicated Libraries: The program calls libraries such as WiFiNINA, WiFi, or ESP8266WiFi. These libraries are essentially a set of encapsulated high-level commands.

2.3 Library-Driven Modules: These libraries send commands (such as AT commands) to the WiFi module at the low level via serial port or other interfaces and parse the data returned from the module.

2.4 Module Execution: The WiFi module receives commands and completes the specific low-level communication details such as network connection and data transmission/reception.

2.5 Result Feedback: The WiFi module returns the results (such as connection status and received data) to the Arduino.

Ⅲ. Conclusion

Differences: Arduino is the control core, responsible for logic; the WiFi module is the communication peripheral, responsible for networking.

Relationship: Arduino controls the WiFi module through hardware interfaces and software libraries. The two work together to connect the physical world (sensors, actuators) with the digital world (the Internet), thus enabling IoT applications. For beginners, starting with ESP32 or NodeMCU is the simplest and most efficient choice, as it perfectly integrates both.