How to set up an Access Point, and what it is good for

platformio.ini

@@ -12,9 +12,3 @@
 platform = espressif32
 board = upesy_wroom
 framework = arduino
-lib_deps = adafruit/Adafruit MPU6050@^2.2.6
-
-; How to change bit-per-second rate for your project:
-; Add right under [env:upesy_wroom]:
-; "monitor_speed = x" (without the "")
-; x == baudrate of selected choice, bsp: 115200, 8000, 300

src/main.cpp

@@ -1,141 +1,154 @@
 //--------------------------------------------------------------------------------------------------------------------------//
-// Setting up the Adafruit_MPU6050 library for the accelerator chip
+// Setting up an Access Point hosted by the ESP32
 //--------------------------------------------------------------------------------------------------------------------------//
 
-// Check the other guide in the .docx as to how to INSTALL the necessary library //
+// What is the difference between an Access Point and using the ESP as a client? //
+// Well, there's a big difference as to how either work, and what is needed. As an Access Point, you can create your own little "network" hosted
+// over the small WLAN module on the developing board. That let's you access a website on the ESP for example, without
+// having to go over any of your internet provider's servers since it's purely local.
+// When hosting an Access Point, you CANNOT log into another Wlan network. Clients (for example your phone) can log into the one on the ESP though.
+// If you want to use an async Webserver, that works better with the use of a router inbetween, and has more advantages all in all.
+// If no internet connection is required and it's for little displayment, a local Access Point should be enough.
 
-// Must be included for most things! //
+#include <Arduino.h>
-#include <Arduino.h> // Only include once of course.
-#include <Adafruit_MPU6050.h>
-#include <Adafruit_Sensor.h>
 
-// Create instance of the sensor library //
+// Load Wifi library //
-Adafruit_MPU6050 mpu;
+#include <WiFi.h>
+
+// Set your network credentials (you are entirely free to choose anything) //
+const char* _ssid = "ESP32-Access-Point"; // for example
+const char* _password = "1234IamAPassword"; // that's a bad example, but you get the gist
+
+// Set up instance and the right port (default: 80) //
+WiFiServer server(80);
+
+// String to save the http adress in //
+String _http = "";
+
+// State variable for the example following in the loop() function later //
+String _output_state = "off";
 
 void setup()
 {
-    Serial.begin(115200); // For Serial communication, check if the right bit-per-second rate is selected!
+    Serial.println("Setting up access point...");
-                          // If you want to change said bit-per-second, look in the .ini file for information.
+    WiFi.softAP(_ssid, _password);
-                          // How do you know the one selected does not work / there's something wrong in the .ini file?
+    IPAddress _IP = WiFi.softAPIP(); // You can see what is hosted on the ESP over this IP address.
-                          // Check the terminal, if that is the case everything printed is Unicode gibberish.
+    Serial.print("AP IP Address: ");
+    Serial.println(_IP);
 
-    while(!Serial) delay(10); // Wait until the Serial communication is set up and initialized.
+    server.begin(); // starts WiFi server.
-    Serial.println("Starting..."); 
-
-    if(!mpu.begin()) // Exception for the case of the mpu not starting up
-    {
-        // If this is the case, check the wiring and whether or not the right pins are connected.
-        // Another issue that could lead to this is too little or too much current going through the chip.
-        Serial.println("Failed to find MPU6050 chip.");
-        while(1)
-        {
-            delay(10);
 }
-    }
-    Serial.println("MPU6050 has been found.");
-
-    mpu.setAccelerometerRange(MPU6050_RANGE_8_G); // Set to the range of your choice for the accelerator values
-                                                  // depending on the range you want your read in values to vary in.
-    Serial.println("Accelerator range set to: ");
-    switch(mpu.getAccelerometerRange()) // Check setting and print for insight.
-    {
-        case MPU6050_RANGE_2_G:
-            Serial.println("+-2G");
-        	break;
-        case MPU6050_RANGE_4_G:
-            Serial.println("+-4G");
-            break;
-        case MPU6050_RANGE_8_G:
-            Serial.println("+-8G");
-            break;
-        case MPU6050_RANGE_16_G:
-            Serial.println("+-16G");
-            break;
-    }
-
-    mpu.setGyroRange(MPU6050_RANGE_500_DEG); 
-    Serial.print("Gyro range set to: ");
-    switch (mpu.getGyroRange()) 
-    {
-        case MPU6050_RANGE_250_DEG:
-            Serial.println("+- 250 deg/s");
-            break;
-        case MPU6050_RANGE_500_DEG:
-            Serial.println("+- 500 deg/s");
-            break;
-        case MPU6050_RANGE_1000_DEG:
-            Serial.println("+- 1000 deg/s");
-            break;
-        case MPU6050_RANGE_2000_DEG:
-            Serial.println("+- 2000 deg/s");
-            break;
-    }
-
-    mpu.setFilterBandwidth(MPU6050_BAND_21_HZ);
-    Serial.print("Filter bandwidth set to: ");
-    switch (mpu.getFilterBandwidth()) 
-    {
-        case MPU6050_BAND_260_HZ:
-            Serial.println("260 Hz");
-            break;
-        case MPU6050_BAND_184_HZ:
-            Serial.println("184 Hz");
-            break;
-        case MPU6050_BAND_94_HZ:
-            Serial.println("94 Hz");
-            break;
-        case MPU6050_BAND_44_HZ:
-            Serial.println("44 Hz");
-            break;
-        case MPU6050_BAND_21_HZ:
-            Serial.println("21 Hz");
-            break;
-        case MPU6050_BAND_10_HZ:
-            Serial.println("10 Hz");
-            break;
-        case MPU6050_BAND_5_HZ:
-            Serial.println("5 Hz");
-            break;
-    }
-
-    delay(100);
-
-    // What is the difference between "void setup()" and "void loop()"? Why put all this in here? //
-    // The setup fuction is only initialized once, and though that's true for the entire lifetime of the programm,
-    // the started services continue to run in here on this threat, allowing the loop to be executed simultaniously.
-    // Mind, and that's IMPORTANT!!, that you should refer from using "while(1)" in this function as much as possible.
-    // (I'm aware there is one in here in this project, but only because it is handled correctly and carefully.)
-}
-
-// Put your variables here for testing, otherwise I'd recommend putting it in a class //
-float _x_accel = 0; // x acceleration
-float _y_accel = 0; // y acceleration
-float _calc = 0; // for calculations
 
 void loop()
 {
-    // Save vals if you want to send them: //
+    // Listen for any incoming clients, you can also create a thread extra for this if little processing power is needed //
-    sensors_event_t _a;
+    WiFiClient _client = server.available();
-    sensors_event_t _g;
+    // If that is the case, make sure to keep the service running. It should not be stopped or interrupted at all if the programm is still running,
-    sensors_event_t _temp; // Used as placeholder for now in the next function, even if you don't need temperature values.
+    // I'd advice to use an exeption / interrupt that is listening in on whether or not a new client or http request has been received.
+    // Be careful with that in general if you try it.
 
-    mpu.getEvent(&_a, &_g, &_temp); // Reads in your values.
+    if(_client)
-
-    _x_accel = _a.acceleration.x; // acceleration in x.
-    _y_accel = _a.acceleration.y; // acceleration in y.
-
-    // Basic example for use //
-    _calc = _y_accel * 12.5; // Calculate postion if you want to.
-    if(_calc > 100) // reduce values if you only want values from (-100) - 100 for example
     {
-        _calc = 100;
+        String _current_line = "";
-    }
+        while(_client.connected()) // As long as the client is connected...
-    else if(_calc < (-100))
         {
-        _calc = (-100);
+            if(_client.available()) // Checks whether or not there is bites to read from.
+            {
+                char _c = _client.read(); // reads a single bite.
+                _http += _c;              // assembling the full http request one by one.
+
+                if(_c != 10)              // Listen in for LF (new line / line feat) since that is
+                                          // a signal for the end of the request.
+                                          // (Side note: Using '\n' here should technicall work here, but can create some errors.)
+                                          // (Use 10 (ASCII) instead to avoid any misleading errors.)
+                {
+                    // Send a response here, since every request needs a response.
+                    // If something went wrong, be sure to send an error message instead of nothing.
+
+                    // Replying: //
+                    if(_current_line.length() == 0)
+                    {
+                        // HTTP headers always start a certain way. So be sure to keep the following format. 
+                        _client.println("HTTP/1.1 200 OK");
+                        _client.println("Content-type:text/html");
+                        _client.println("Connection: close");
+                        _client.println();
+                        // And there you go, a correct response that a client can work with!
+
+                        // Now you can technically compute whatever changes the client might have requested,
+                        // whether that was a press of a button or a press on a link. Any action needs to be responded to,
+                        // or else one might end up in the void of white like a blank page, or nothing happens.
+                        // The following is an example of how you would process requests with a html button.
+
+                        // NOTE! This is html code written inside a C/C++ code. It's far from optional, and SPIFFS is therefor recommended if a
+                        // seperate html & css file is prefered. You can read about that in the tutorial branch to the Async Server.
+                        // For now, this is purely for demonstration.
+
+                        // Handling the change of the example button //
+                        if (_http.indexOf("GET Button on") >= 0) 
+                        {
+                            Serial.println("Button turned on");
+                            _output_state = "on";
+                            // digitalWrite(PIN, HIGH); // == how you would pull a Pin up when the button activates.
+                        }
+                        else if (_http.indexOf("GET Button off") >= 0) 
+                        {
+                            Serial.println("Button turned off");
+                            _output_state = "off";
+                            // digitalWrite(PIN, LOW); // again for example.
                         }
 
-    // And done! //
+                        // Displaying the site //
-    // Mind that everything in this loop repeats itself over and over, only stopping until the programm fails to execute or //
+                        _client.println("<!DOCTYPE html><html>");
-    // the current is cut. If you'd like to restart everything, press the little button titled "RST" or "BOOT" (if the first does nothing) on the ESP. // 
+                        _client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
+                        _client.println("<link rel=\"icon\" href=\"data:,\">");
+
+                        // Set up a button //
+                        _client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
+                        _client.println(".button { background-color: #4CAF50; border: none; color: white; padding: 16px 40px;");
+                        _client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
+                        _client.println("</style></head>"); // closes the style tag.
+
+                        if (_output_state=="off") 
+                        {
+                            _client.println("<p><a href=\"Button on\"><button class=\"button\">ON</button></a></p>");
                         }  
+                        else 
+                        {
+                            _client.println("<p><a href=\"Button off\"><button class=\"button button2\">OFF</button></a></p>");
+                        } 
+
+                        // End the HTTP response with a LF as well //
+                        _client.println();
+                        break;
+                    }
+                    else // received a LF, clear the current line for input.
+                    {
+                        _current_line = "";
+                     }
+                } // end of if()
+                else if(_c != 13) // Handles the exeption for if you got anything but a carriage return.
+                                  // NOTE! Technically, '\r' should also work, but like '\n', it can cause issues.
+                                  // (Once more use 13 (ASCII) instead)
+                {
+                    _current_line += _c;
+                }
+            } // end of if()
+        } // end of while()
+
+        // Clear the request variable for later use //
+        _http = "";
+
+        // Close the connection to the client //
+        _client.stop();
+        Serial.println("Client disconnected.");
+        Serial.println();
+        
+        // For every time the loop repeats, a new client and a new http request is being processed.
+    }
+}
+
+// As said, the example is a tedious an impractical way to host reactive html code.
+// Yet, it's enough for simple and fast displaying of values over a local WiFi Webserver.
+
+// Still, since it needs an entire thread to run, it's far from the ideal way.