Table of Contents
IOT1: Reading MAC address of the WiFi
Each network IP card is supposed to have a unique MAC address. ESP32 chip has built-in MAC. MAC can be used to identify devices, but note that it is not a “strong” ID: it can be programmatically changed and easily discovered. In the following scenario, we only present how to read the MAC address. A part regarding displaying on the selected screen is up to the developer. You can refer to the appropriate scenario, as listed below.
Prerequisites
To implement this scenario, it is necessary to get familiar with at least one of the following scenarios first:
A WiFi library is already included in the Arduino framework for ESP32, so there is no need to add it to the platformio.ini explicitly.
Suggested Readings and Knowledge Resources
Hands-on Lab Scenario
Task to be implemented
Present a MAC address on the selected display. The steps below present only the reading part, not a display. Handling a display is presented in the EMBx scenarios, as listed above.
Start
Check if you can see a full LCD in your video stream. Book a device and create a dummy Arduino file with void setup()… and void loop()….
Steps
Step 1
Include the WiFi management library in your source code:
#include <WiFi.h>
The WiFi library automatically initialises a singleton class WiFi that you can use to set up working mode, read MAC, and perform many other operations.
Step 2
Reading the MAC as a String is as easy as simply calling:
WiFi.macAddress();
Result validation
Using another node should change the MAC read. Book another device and discover its MAC.
FAQ
Can I change MAC?: Actually, yes, you can. It is not advised, however, because you may accidentally generate an overlapping address that will collide with another device in the same network. You must first explicitly configure the ESP32 chip to work as an AP (Access Point, Server) or STA (WiFi Client) to do it. Sample stub code (for STA) may look as follows:
#include <WiFi.h> #include <esp_wifi.h> uint8_t newMAC[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xCA, 0xFE}; //Array of bytes with new MAC void setup() { WiFi.mode(WIFI_STA); esp_wifi_set_mac(WIFI_IF_STA, &newMAC[0]); }
