Building an ESP32-Based Network Speed Monitor

Ever wondered how fast your WiFi network really is? While internet service providers promise high speeds, real-world performance can fluctuate due to network congestion, signal interference, or hardware limitations.

In this tutorial, we’ll build an ESP32-based WiFi Network Speed Monitor that runs periodic tests and displays results in requests per second (req/s) or megabits per second (Mbps). This IoT-powered speed test will help monitor network stability and detect downtime.

What You’ll Learn:

• Connecting an ESP32 to WiFi
• Sending HTTP requests and measuring response time
• Calculating network speed in Mbps
• Displaying speed metrics via Serial Monitor or OLED
• Implementing an automatic network health check

Required Components

Before starting, ensure you have the following:

• ESP32 Development Board
• WiFi Connection (2.4GHz recommended for ESP32)
• Arduino IDE (with ESP32 Board installed)
• Jumper Wires (if using a display)
• OLED Display (Optional)

How the ESP32 Network Speed Test Works

• WiFi Connection: ESP32 connects to your WiFi network.
• HTTP Requests: It sends multiple requests to a test server (httpbin.org).
• Response Time Measurement: Calculates request duration to estimate network speed.
• Data Processing: Converts speed into requests per second or megabits per second (Mbps).
• Display Results: Outputs results via Serial Monitor or an OLED screen.

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Setting Up Arduino IDE

Before writing code, install the following libraries:

• WiFi.h - ESP32 WiFi connectivity
• WiFiClientSecure.h - Secure HTTPS requests
• ArduinoJson.h - (Optional) For handling API data

To install:

• Open Arduino IDE → Go to Sketch → Include Library → Manage Libraries
• Search for WiFiClientSecure, ArduinoJson, and install them.

ESP32 Network Speed Test Code

Here’s the complete ESP32 code to measure WiFi speed in requests per second and Mbps

#include <WiFi.h>
#include <WiFiClientSecure.h>

const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

const char* testHost = "httpbin.org";  // Test server for HTTP requests
const int testPort = 80;

WiFiClient client;

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);

  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi!");
}

void loop() {
  Serial.println("Testing network speed...");

  int numRequests = 10;  // Number of HTTP requests
  long startTime = millis();

  for (int i = 0; i < numRequests; i++) {
    if (client.connect(testHost, testPort)) {
      client.print(String("GET /get HTTP/1.1\r\n") +
                   "Host: " + testHost + "\r\n" +
                   "Connection: close\r\n\r\n");

      while (!client.available()) {
        delay(10);
      }
      
      while (client.available()) {
        client.read();
      }
      client.stop();
    } else {
      Serial.println("Connection failed!");
    }
  }

  long elapsedTime = millis() - startTime;
  float speedReqSec = (float)numRequests / (elapsedTime / 1000.0);
  float speedMbps = (numRequests * 0.2 * 8) / (elapsedTime / 1000.0); // Approx. 200 bytes per request

  Serial.print("Network speed: ");
  Serial.print(speedReqSec);
  Serial.println(" requests per second");

  Serial.print("Download speed: ");
  Serial.print(speedMbps);
  Serial.println(" Mbps");

  delay(60000);  // Run test every 1 minute
}

Code Explanation

• Connects ESP32 to WiFi
• Sends 10 HTTP requests to httpbin.org
• Measures total time taken for all requests

Calculates speed:

• Requests per second (req/s)
• Download speed (Mbps) using DataSize * 8 / TimeTaken formula
• Repeats speed test every 60 seconds

Displaying Data on an OLED Screen (Optional)

If you’d like visual feedback, connect an SSD1306 OLED display and modify the code:

#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
}

void loop() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 10);
  display.println("Speed: " + String(speedMbps) + " Mbps");
  display. Display();
}

Enhancements & Future Improvements

You can extend this project by: ✅ Adding a Web Dashboard – ESP32 hosts a web page displaying results. ✅ Storing Data – Log speed trends using Firebase or an SD card. ✅ Real-time Alerts – Trigger a notification when the WiFi speed drops below a threshold.

Conclusion

With this ESP32-powered network speed monitor, you can check WiFi performance, detect fluctuations, and even automate connectivity testing for smart home applications. 🚀