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13. Networking and communications

Instruction

individual assignment:

  • design, build, and connect wired or wireless node(s)with network or bus addresses → Here

group assignment:

  • send a message between two projects → In this page

What I did in this week

  • Test board by serial connection → in this page

  • Running servo motors from my smartphone (between 2 projects) → in this page

Preparation

additional boards manager URLs:

https://dl.espressif.com/dl/package_esp32_index.json

Install board manager

ESP32

esp_install.png

The board I used

ESP32-cam

esp32.jpg

ESP32-CAM.png

Note : When Programmingm, connect IO0 to GND in order to short circuit

Test board by serial connection

Reference for this trial

Wiring

wiring.jpeg

Short-circuit to write for board

short.jpeg

Code

void setup()
{
  Serial.begin(9600); // The connection speed
}

void loop()
{
  Serial.println("Hello, World"); // output "Hello, World"
  delay(1000); // wait for 1 second
}

Arduino Setting

arduino_setting.png

After writing is completed, remove the short-circuit between IO0 and GND to start serial communication

Note:

Select Bootloader ModeGPIO0

The ESP32 will enter the serial bootloader when GPIO0 is held low on reset. Otherwise it will run the program in flash.

GIO0 Input mode
Low/GND ROM serial bootloader for esptool
High/VCC Normal execution mode
GIO0 Input mode
Low/GND ROM serial bootloader for esptool
High/VCC Normal execution mode

GPIO0 has an internal pullup resistor, so if it is left unconnected then it will pull high.

CheckSerial monitor

hello.png

Displayed “Hello, World” → success

Running servo motors from my smartphone

Inspired by : Switch bot

Wiring

connect the servo motor to the board

esp32_serbo.jpeg

Conneciton

Code

//Put the & at the end of the URL parameter when you access it!

#include <WiFi.h>

// Rewrite it to the Wi-Fi you use and its password
const char* ssid     = "fablabkannai";
const char* password = "XXXXXXXXXXX";

// using port 80
WiFiServer server(80);

// Variable to store HTTP requests
String header;

// Variables used to set values
String valueString = String(5);
String delay_valueString = String(500);
int pos1 = 0;
int pos2 = 0;

//pin
const int servo_pin = 16;

//Servo motor rotation angle
const int servo_left   = 26;
const int servo_center = 75;
const int servo_right  = 123;

void setup() {
  pinMode(4, OUTPUT);

  //ledc setting
  ledcSetup(0, 50, 10);  // 0ch 50 Hz 10bit resolution
  ledcAttachPin(servo_pin, 0); // 15pin, 0ch

  //Start of serial communication
  Serial.begin(115200);

  //Flashing flashlight at startup
  for(int i=0; i<5; i=i+1) {
    digitalWrite(4, HIGH);
    delay(50);
    digitalWrite(4, LOW);
    delay(50);
  }

  // Connect to Wi-Fi
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  // Show local IP (access this IP from your phone, etc.)
  Serial.println("");
  Serial.println("WiFi connected.");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  server.begin();
}

void loop(){
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
    Serial.println("New Client.");          // print a message out in the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        header += c;
        if (c == '\n') {                    // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println();

            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\" http-equiv=\"content-type\" charset=\"utf-8\"><title>ESP32 servo controller</title>");

            // CSS to style the on/off buttons
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>.block{display: inline-block; vertical-align: middle; height: 50px; font-size: 0;}");
            client.println(".btn-square-shadow {display: inline-block; width: 300px; height: 50px; text-decoration: none; background: #668ad8; color: #FFF; border-bottom: solid 4px #627295; border-radius: 3px; font-size: 30px;}");
            client.println(".btn-square-shadow:active {-webkit-transform: translateY(4px); transform: translateY(4px);  box-shadow: 0px 0px 1px rgba(0, 0, 0, 0.2);  border-bottom: none;}");
            client.println("</style>");
            client.println("<script src=\"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js\"></script>");

            // Web Page
            client.println("</head><body style='text-align: center;'><h1>ESP32 サーボモーター　コントロールパネル</h1>");
            //servo slide bar <--------------------------------------------------------------------------------------------------------------------------------------------------------------------ESP32's IP address. To find open serial monitor with 115200bps
            client.println("<div class='left block'> <a href='http://192.168.1.173/?angle=50&delay=500&'><button id='entrance_button' class='btn-square-shadow' type='button'>Turn on Fan</button></a></div>");          
            client.println("<div class='right block'><a href='http://192.168.1.173/?angle=100&delay=500&'><button id='room_button' class='btn-square-shadow' type='button'>Turn on Light</button></a></div>");
            client.println("</body></html>");     

            //Processing part of HTTP request
            delay_valueString = "500";
            pos1 = header.indexOf('=',18);
            pos2 = header.indexOf('&',18);
            if(pos1!=-1 && pos2!=-1) {
              delay_valueString = header.substring(pos1+1, pos2);
              Serial.print("pos:");
              Serial.println(pos1);
              Serial.println(pos2);

            } else {
              Serial.print("default servo standby time:");
              Serial.println(delay_valueString.toInt());
            }
            Serial.print("Servo standby time:");
            Serial.println(delay_valueString.toInt());

            pos1 = header.indexOf('=');
            pos2 = header.indexOf('&');
            valueString = header.substring(pos1+1, pos2);
            Serial.print("URL parameter:");
            Serial.println(valueString);

            if(valueString.toInt()>=26 && valueString.toInt()<=123) {

              //Rotate servo motor
              digitalWrite(4, HIGH);
              delay(50);
              digitalWrite(4, LOW);

              ledcWrite(0, servo_center);
              delay(delay_valueString.toInt());
              ledcWrite(0, valueString.toInt());
              delay(delay_valueString.toInt());
              ledcWrite(0, servo_center);
              // バグ防止
              delay(delay_valueString.toInt());
              ledcWrite(0, 0);

              digitalWrite(4, HIGH);
              delay(50);
              digitalWrite(4, LOW);

            } else {
              Serial.println("URLパラメーター　エラー！");
            }

            // End of HTTP Response
            client.println();
            // Break out of the while loop
            break;
          } else {
            currentLine = "";
          }
        } else if (c != '\r') {
          currentLine += c;
        }
      }
    }
    // Clear the header variable
    header = "";
    // Disconnect
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}

Howrver Error is occured. Error messege is below

Arduino: 1.8.19 (Mac OS X), Board: "ESP32 Wrover Module, Huge APP (3MB No OTA/1MB SPIFFS), QIO, 80MHz, 921600, None"

Sketch uses 718866 bytes (22%) of program storage space. Maximum is 3145728 bytes.
Global variables use 38504 bytes (11%) of dynamic memory, leaving 289176 bytes for local variables. Maximum is 327680 bytes.
esptool.py v3.0-dev
Traceback (most recent call last):
  File "esptool.py", line 3969, in <module>
  File "esptool.py", line 3962, in _main
  File "esptool.py", line 3551, in main
  File "esptool.py", line 271, in __init__
Serial port /dev/cu.usbmodem101
  File "serial/__init__.py", line 88, in serial_for_url
  File "serial/serialposix.py", line 268, in open
serial.serialutil.SerialException: [Errno 2] could not open port /dev/cu.usbmodem101: [Errno 2] No such file or directory: '/dev/cu.usbmodem101'
Failed to execute script esptool
An error occurred while uploading the sketch
processing.app.SerialException: Error opening serial port '/dev/cu.usbmodem101'.
    at processing.app.Serial.<init>(Serial.java:152)
    at processing.app.Serial.<init>(Serial.java:82)
    at processing.app.SerialMonitor$2.<init>(SerialMonitor.java:132)
    at processing.app.SerialMonitor.open(SerialMonitor.java:132)
    at processing.app.AbstractMonitor.resume(AbstractMonitor.java:132)
    at processing.app.Editor.resumeOrCloseSerialMonitor(Editor.java:2126)
    at processing.app.Editor.access$1300(Editor.java:116)
    at processing.app.Editor$UploadHandler.run(Editor.java:2095)
    at java.lang.Thread.run(Thread.java:748)
Caused by: jssc.SerialPortException: Port name - /dev/cu.usbmodem101; Method name - openPort(); Exception type - Port not found.
    at jssc.SerialPort.openPort(SerialPort.java:167)
    at processing.app.Serial.<init>(Serial.java:141)
    ... 8 more
Error opening serial port '/dev/cu.usbmodem101'.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Unplug and retry servo motors → success!

open the serial monitor

serial.png

get the local adress

http://192.168.1.173/

Write the right local address in the sketch.

However, error occured

Arduino: 1.8.19 (Mac OS X), Board: "ESP32 Wrover Module, Huge APP (3MB No OTA/1MB SPIFFS), QIO, 80MHz, 921600, None"

Sketch uses 718866 bytes (22%) of program storage space. Maximum is 3145728 bytes.
Global variables use 38504 bytes (11%) of dynamic memory, leaving 289176 bytes for local variables. Maximum is 327680 bytes.
esptool.py v3.0-dev
Serial port /dev/cu.usbmodem1101
Connecting........_____....._____....._____....._____....._____....._____.....____An error occurred while uploading the sketch
_

A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Replace new connector connecting IO0 and GND and retry

→ success

Open in browser

http://192.168.1.173/?angle=50&delay=500&

iphone_display.jpeg

informationtworking

Connect the servo motor to the fan in order to control switching of the fan

fan.jpeg

Attach to fan and switch on/off

Yey!

What I learned in this week

→ Individual page

Last update: May 4, 2022