Week 11: Networking and Communications
Assignments:
Group Assignment
- Send a message between two projects
- Document your work to the group work page and reflect on your individual page what you learned
Individual Assignment
- Design, build, and connect wired or wireless node(s) with network or bus addresses and local input &/or output device(s)
Things to Complete This Week
- Explore and test different sensors
- Document process
- Work on Final Project PCB!!!
Here is my schedule for this week.
Here is the link to my schedule
Group Assignment
You can access our group assignment here.
Individual Assignment
Difference between Wired and Wireless Connections
A wired connection uses physical cables (like USB or Ethernet) to link devices together. This means that data travels directly through the wire, making the connection usually faster, more stable, and less affected by interference. The downside is that you’re limited by the length of the cable, so you can’t move around freely.
A wireless connection sends data through the air using signals like Wi-Fi or Bluetooth. This allows devices to connect without cables, giving you more freedom to move and making things more convenient. However, wireless connections can sometimes be slower or less reliable due to distance, obstacles, or signal interference.
This week, I decided to create a web-based control for the LED on my board (The one that I designed during Electronics Production week).
Here are the steps I followed to do exactly that:
Note: I went through Seeed Studio's official page to get the codes for scanning different Wi-Fi networks and then connecting to one after that. You can access the guide by clicking on this link.
1. I started by connecting the Wi-Fi antenna to my XIAO ESP32C3. I then connected a USB type-C cable to the XIAO.
2. Next I copy-pasted the first code which was given in the guide above for scanning different Wi-Fi networks.
#include "WiFi.h"
void setup() {
Serial.begin(115200);
// Set WiFi to station mode and disconnect from an AP if it was previously connected
WiFi.mode(WIFI_STA);
WiFi.disconnect();
delay(100);
Serial.println("Setup done");
}
void loop() {
Serial.println("scan start");
// WiFi.scanNetworks will return the number of networks found
int n = WiFi.scanNetworks();
Serial.println("scan done");
if (n == 0) {
Serial.println("no networks found");
} else {
Serial.print(n);
Serial.println(" networks found");
for (int i = 0; i < n; ++i) {
// Print SSID and RSSI for each network found
Serial.print(i + 1);
Serial.print(": ");
Serial.print(WiFi.SSID(i));
Serial.print(" (");
Serial.print(WiFi.RSSI(i));
Serial.print(")");
Serial.println((WiFi.encryptionType(i) == WIFI_AUTH_OPEN) ? " " : "*");
delay(10);
}
}
Serial.println("");
// Wait a bit before scanning again
delay(5000);
}
What does the code do? 🤷♂️
This code makes your board scan for Wi-Fi networks nearby. In setup(), it starts the serial monitor so you can see messages on your computer and sets the Wi-Fi to “station mode” (ready to connect to networks) while disconnecting from any previous network. Then in the loop(), it continuously scans for networks, printing messages like “scan start” and “scan done.”
It counts how many networks it finds and, for each one, it shows the network name (SSID), signal strength (RSSI), and whether it’s open or secured. After each scan, it waits 5 seconds and repeats.
You can see the nearby networks in the serial monitor:
3. I then copy-pasted this code (also from the guide above) to connect to a WI-FI network.
#include "WiFi.h"
const char* ssid = "your-ssid";
const char* password = "your-password";
void setup() {
Serial.begin(115200);
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void loop() {}
What does the code do? 🤷♀️
The code tries to connect to the network using the ssid and password that you provide. While it’s connecting, it prints dots to show that it’s still trying. Once connected, it prints “WiFi connected” and shows the board’s IP address on the network. The loop() is empty, so after connecting, the board just stays connected without doing anything else.
Even though you’ll need to reconnect to a network later, I feel like this step can be used to test if the network is working properly.
4. I then asked ChatGPT (my bestfriend these days 🫠) to generate me a code for setting up my web server. This was the prompt that I used: Make me an ESP32 Arduino code to control the built-in LED on pin D8 with a web page. I want six buttons: ON, OFF, Blink 3 times, Blink slow, Blink fast, and Heartbeat. Clicking a button should do that action on the LED on my board. Make the web page light pink with black elements, and show messages in the Serial Monitor whenever a pattern starts and stops. It came out to be quite long 🤯.
#include <WiFi.h>
#include <WebServer.h>
const char* ssid = "Your ssid";
const char* password = "password";
const int ledPin = 8; // Built-in LED pin (D8)
WebServer server(80);
// Function to blink LED a specific number of times
void blinkLED(int times, int delayTime) {
Serial.print("Blinking LED ");
Serial.print(times);
Serial.println(" times.");
for (int i = 0; i < times; i++) {
digitalWrite(ledPin, HIGH);
delay(delayTime);
digitalWrite(ledPin, LOW);
delay(delayTime);
}
Serial.println("Blink done.");
}
// Heartbeat pattern (like a heart pulse)
void heartbeat() {
Serial.println("Heartbeat started.");
digitalWrite(ledPin, HIGH);
delay(200);
digitalWrite(ledPin, LOW);
delay(200);
digitalWrite(ledPin, HIGH);
delay(200);
digitalWrite(ledPin, LOW);
delay(600);
Serial.println("Heartbeat done.");
}
// Handlers for each button
void handleOn() {
Serial.println("LED turned ON");
digitalWrite(ledPin, HIGH);
server.send(200, "text/html", webPage());
}
void handleOff() {
Serial.println("LED turned OFF");
digitalWrite(ledPin, LOW);
server.send(200, "text/html", webPage());
}
void handleBlink3() {
blinkLED(3, 250);
server.send(200, "text/html", webPage());
}
void handleBlinkSlow() {
blinkLED(5, 500);
server.send(200, "text/html", webPage());
}
void handleBlinkFast() {
blinkLED(10, 100);
server.send(200, "text/html", webPage());
}
void handleHeartbeat() {
heartbeat();
server.send(200, "text/html", webPage());
}
// HTML web page with light pink background
String webPage() {
String html = "<!DOCTYPE html><html><head>";
html += "<meta name='viewport' content='width=device-width, initial-scale=1.0'>";
html += "<title>ESP32 LED Control</title>";
html += "<style>";
html += "body { background-color: lightpink; color: white; font-family: Arial; text-align:center; }";
html += "button { background-color: black; color: white; padding: 15px 25px; margin: 10px; font-size:16px; border:none; cursor:pointer; }";
html += "button:hover { background-color: gray; }";
html += "</style></head><body>";
html += "<h1>ESP32 LED Control</h1>";
html += "<button onclick="location.href='/on'">ON</button>";
html += "<button onclick="location.href='/off'">OFF</button>";
html += "<button onclick="location.href='/blink3'">Blink 3 times</button>";
html += "<button onclick="location.href='/blinkSlow'">Blink slow</button>";
html += "<button onclick="location.href='/blinkFast'">Blink fast</button>";
html += "<button onclick="location.href='/heartbeat'">Heartbeat</button>";
html += "</body></html>";
return html;
}
void setup() {
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, LOW);
Serial.begin(115200);
delay(10);
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected.");
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
// Set up routes
server.on("/", [](){ server.send(200, "text/html", webPage()); });
server.on("/on", handleOn);
server.on("/off", handleOff);
server.on("/blink3", handleBlink3);
server.on("/blinkSlow", handleBlinkSlow);
server.on("/blinkFast", handleBlinkFast);
server.on("/heartbeat", handleHeartbeat);
server.begin();
Serial.println("HTTP server started.");
}
void loop() {
server.handleClient();
}
5. After uploading the code, you should see the same "WIFI connected" message like you did in step 3.
6. I copied the IP address and pasted it into my browser (Google Chrome). Here is how my webserver turned out! 🥳💃
Testing 🤗
In the serial monitor, you can also see all your activities 😯:
It's really fascinating to see how wireless communication works. At the beginning of the week, I thought that doing the assignment was going to be really hard but it wasn't all that bad (What I did was pretty simple though 😛😅). Even so, I feel like I was able to learn a great deal. 🥳