Chance Jiajie Li/Week11 - networking and communications

Created Wed, 22 Nov 2023 00:44:03 -0500 Modified Wed, 29 Nov 2023 13:34:36 -0500
577 Words

Week11 - networking and communications

Assignment

individual assignment:

  • design, build, and connect wired or wireless node(s) with network or bus addresses and a local interface

group assignment:

  • send a message between two projects

Idea

  1. mqtt data receiver
  2. web compass
  3. spatial relationship detection between modular components

Wi-Fi Scan and Connect

  • Scan

    #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);
}

  • Connect

    #include <WiFi.h>

const char* ssid     = "ESP_0672F1";
const char* password = "";   

void setup()
{
    Serial.begin(115200);
    delay(10);

    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()
{
  }

Tesing

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_HMC5883_U.h>
#include <WiFi.h>
#include <WiFiClient.h>
#include <WebServer.h>
#include "mainpage.h"
#include "jscript.h"

/* Assign a unique ID to this sensor at the same time */
Adafruit_HMC5883_Unified mag = Adafruit_HMC5883_Unified(12345);

//provide your own WiFi SSID and password
const char* ssid     = "";
const char* password = "";   

float xMax, yMax, xMin, yMin = 0.0;

WebServer server(80);

//For storing data as string
String text= "";

void setup(void) 
{
  Serial.begin(9600);
  Serial.println("HMC5883 Magnetometer Test"); Serial.println("");
  
  /* Initialise the sensor */
  if(!mag.begin())
  {
    /* There was a problem detecting the HMC5883 ... check your connections */
    Serial.println("Ooops, no HMC5883 detected ... Check your wiring!");
    while(1);
  }

  //Use ESP32 as WiFi Station
  WiFi.mode(WIFI_STA);
  //Initiate WiFi Connection
  WiFi.begin(ssid, password);
  Serial.println("");
  // Wait for connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to ");
  //Print your WiFi's SSID (might be insecure)
  Serial.println(ssid);
  Serial.print("IP address: ");
  //Print your local IP address (needed for browsing the app)
  Serial.println(WiFi.localIP());
   //Home page. Contents of 'page' is in mainpage.h
  server.on("/", []() {
   server.send(200, "text/html", page);
  });
  //JavaScript! Contents of 'javascript' is in jscript.h
  server.on("/jscript.js", []() {
   server.send(200, "text/javascript", javascript);
  });
  //Page for reading data. Sensor is read in this part
  server.on("/data", [](){
    delay(100);
    /* Get a new sensor event */ 
    sensors_event_t event; 
    mag.getEvent(&event);

    if (xMax == 0.0) {
      xMax = event.magnetic.x;
    }

    if (yMax == 0.0) {
      yMax = event.magnetic.y;
    }

    xMax = max(xMax, event.magnetic.x);
    yMax = max(yMax, event.magnetic.y);
    xMin = min(xMin, event.magnetic.x);
    yMin = min(yMin, event.magnetic.y);

    float ymax_rounded = round(yMax * 100) / 100.0;
    float ymin_rounded = round(yMin * 100) / 100.0;
    float xmax_rounded = round(xMax * 100) / 100.0;
    float xmin_rounded = round(xMin * 100) / 100.0;

    float heading = atan2((event.magnetic.y - ((yMax + yMin) / 2.0)), (event.magnetic.x - ((xMax + xMin) / 2.0)));
    
    // Correct for when signs are reversed.
    if(heading < 0)
      heading += 2*PI;
      
    // Check for wrap due to addition of declination.
    if(heading > 2*PI)
      heading -= 2*PI;
     
    // Convert radians to degrees for readability.
    float headingDegrees = heading * 180/M_PI; 
    text = (String)headingDegrees;
    server.send(200, "text/plain", text);

    // Output the heading to the console
    Serial.print("Heading: ");
    Serial.println(heading);
  });
  //start web server
  server.begin();
  //Just stating things
  Serial.println("HTTP server started");
}

void loop(void) 
{
  //Make the ESP32 always handle web clients
  server.handleClient();
}