ESP32: Laboratorios

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ESP32: Laboratórios

A placa Heltec ESP32 LoRa é uma placa de desenvolvimento que integra três formas distintas de comunicação: Wifi, Bluetooth e a rede de comunicação de longo alcance LoRa. Além disto a placa apresenta um display OLED, o que facilita o controle da operação do dispositivo localizado em locais remotos.

[1]

Referências sobre o Heltec ESP32
Instalação da placa do Heltec ESP32 com a IDE do Arduino
  1. IDE -> Arquivo -> Preferências
  2. URLs Adicionais para Gerenciadores de Placa: https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series/releases/download/0.0.5/package_heltec_esp32_index.json
  3. Ferramentas -> Gerenciadores de Placa -> Instalar Heltec ESP32 Series Dev/boards
  4. Selecionar placa WiFi LoRa 32

Laboratório 1: Wifi

Exemplo pronto da biblioteca padrão do Arduino: Arquivo -> Exemplos -> Wifi -> SimpleWifiServer:

  • Configurar apenas ssid e passwd da rede Wifi;
  • Identificar via terminal serial o endereço IP recebido pelo ESP32;
  • Será possível controlar led (gpio 5, ou outro) via nagerador Web.

Laboratório 2: Bluetooth

Exemplo pronto da biblioteca padrão do Arduino: Arquivo -> Exemplos -> BluetoothSerial -> SerialToSerialBT:

Exemplo de interação bluetooth entre ESP32 e Android Serial Bluetooth Terminal.
  • Carregar código no ESP32;
  • Instalar aplicativo Serial Bluetooth Terminal no Android;
  • Parear o ESP32 com o Android;
  • Trocar mensagens seriais entre o terminal do ESP32 e o aplicativo Serial Bluetooth Terminal

Laboratório 3: Bluetooth Low Energy - BLE

Ver detalhes do BLE: https://randomnerdtutorials.com/esp32-bluetooth-low-energy-ble-arduino-ide/.

Biblioteca: https://github.com/nkolban/ESP32_BLE_Arduino
  • Exemplo pronto Arquivo -> Exemplos -> ESP BLE Arduino -> BLEserver;
  • Instalar aplicativo BLE Terminal no Android;
  • Conectar ao dispositivo.

Laboratório 4: Servidor Web e Display OLED

Exemplo de Web Server construído a partir de dois exemplos prontos:

  • Wifi: busca de redes e conexão baseadas no exemplo:
Arquivo -> Exemplos -> Heltec ESP Dev-Boards -> Factory_Tests -> WIFI_Kit_32_Factory_Test
  • Servidor Web: baseado no exemplo:
Arquivo -> Exemplos -> Wifi -> SimpleWiFiServer

Código

/*
 * Web Server
 * 
 * Wifi: busca de redes e conexão baseadas no exemplo:
 * Arquivo -> Exemplos -> Heltec ESP Dev-Boards -> Factory_Tests -> WIFI_Kit_32_Factory_Test
 * 
 * Servidor Web: baseado no exemplo:
 * Arquivo -> Exemplos -> Wifi -> SimpleWiFiServer
*/

#include "heltec.h"
#include "WiFi.h"
#include "images.h"

WiFiServer server(80);

void logo(){
	Heltec.display -> clear();
	Heltec.display -> drawXbm(0,5,HelTec_LOGO_width,HelTec_LOGO_height,(const unsigned char *)HelTec_LOGO_bits);
	Heltec.display -> display();
  delay(1000);
  Heltec.display->clear();
}

void wifi_logo(){
  Heltec.display -> clear();
  Heltec.display->drawXbm(34, 19, WiFi_Logo_width, WiFi_Logo_height, WiFi_Logo_bits);
  Heltec.display -> display();
  delay(1000);
  Heltec.display->clear();
}


void WIFISetUp(void)
{
	// Set WiFi to station mode and disconnect from an AP if it was previously connected
	WiFi.disconnect(true);
	delay(1000);
	WiFi.mode(WIFI_STA);
	WiFi.setAutoConnect(true);
	WiFi.begin("SSID","passwd");
	delay(100);

	byte count = 0;
	while(WiFi.status() != WL_CONNECTED && count < 10)
	{
		count ++;
    if (count == 1) Serial.println("Connecting...");
		delay(500);
    Heltec.display->clear();
		Heltec.display -> drawString(0, 0, "Connecting...");
		Heltec.display -> display();
	}

	Heltec.display -> clear();
	if(WiFi.status() == WL_CONNECTED)
	{
		Heltec.display -> drawString(0, 0, "Connecting...OK.");
		Heltec.display -> display();
		delay(500);
    Heltec.display -> drawString(0, 10, "IP address: ");
    Heltec.display -> display();
    delay(500);
    Heltec.display -> drawString(0, 20, WiFi.localIP().toString());
    Heltec.display -> display();
    delay(2000);
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
	}
	else
	{
		Heltec.display -> clear();
		Heltec.display -> drawString(0, 0, "Connecting...Failed");
		Heltec.display -> display();
    Serial.println("Connecting...Failed");
//		while(1);
	}
	Heltec.display -> drawString(0, 40, "WIFI Setup done");
	Heltec.display -> display();
  Serial.println("WIFI Setup done");
	delay(500);
  Heltec.display->clear();
}

void WIFIScan(void)
{
	Heltec.display -> drawString(0, 20, "Scan start...");
	Heltec.display -> display();
  Serial.println("Scan start...");

	int n = WiFi.scanNetworks();
	Heltec.display -> drawString(0, 30, "Scan done");
	Heltec.display -> display();
  Serial.println("Scan done");
	delay(500);
	Heltec.display -> clear();

	if (n == 0)
	{
		Heltec.display -> clear();
		Heltec.display -> drawString(0, 0, "no network found");
		Heltec.display -> display();
    Serial.println("No network found");
		while(1);
	}
	else
	{
    Serial.print(n);
		Heltec.display -> drawString(0, 0, (String)n);
		Heltec.display -> drawString(14, 0, "networks found:");
		Heltec.display -> display();
    Serial.print(n);
    Serial.println(" networks found:");
		delay(500);

		for (int i = 0; i < n; ++i) {
		// Print SSID and RSSI for each network found
			Heltec.display -> drawString(0, (i+1)*9,(String)(i + 1));
			Heltec.display -> drawString(6, (i+1)*9, ":");
			Heltec.display -> drawString(12,(i+1)*9, (String)(WiFi.SSID(i)));
			Heltec.display -> drawString(90,(i+1)*9, " (");
			Heltec.display -> drawString(98,(i+1)*9, (String)(WiFi.RSSI(i)));
			Heltec.display -> drawString(114,(i+1)*9, ")");
			//            display.println((WiFi.encryptionType(i) == WIFI_AUTH_OPEN)?" ":"*");
      Serial.print(i+1);
      Serial.print(" : ");
      Serial.print(WiFi.SSID(i));
      Serial.print(" (");
      Serial.print(WiFi.RSSI(i));
      Serial.println(")");
			delay(10);
		}
	}

	Heltec.display -> display();
	delay(800);
	Heltec.display -> clear();

}

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

	Heltec.begin(true /*DisplayEnable Enable*/, false /*LoRa Enable*/, true /*Serial Enable*/);

	logo();
  wifi_logo();
  WIFIScan();
	WIFISetUp();
    
  //WiFi.disconnect(true);//重新初始化WIFI
  //delay(1000);
  //WiFi.mode(WIFI_STA);
  //WiFi.setAutoConnect(true);

  server.begin();
  Heltec.display -> drawString(0, 0, "Waiting Web Clients");
  Heltec.display -> display();

}

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

  if (client) {                             // if you get a client,
    Serial.println("New Client.");           // print a message out the serial port
    Heltec.display -> clear();
    Heltec.display -> drawString(0, 0, "New Web Client");
    Heltec.display -> display();
    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
        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();
            // the content of the HTTP response follows the header:
            client.print("Click <a href=\"/H\">here</a> to turn the LED on.<br>");
            client.print("Click <a href=\"/L\">here</a> to turn the LED off.<br>");

            // The HTTP response ends with another blank line:
            client.println();
            // break out of the while loop:
            break;
          } else {    // if you got a newline, then clear currentLine:
            currentLine = "";
          }
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine
        }

        // Check to see if the client request was "GET /H" or "GET /L":
        if (currentLine.endsWith("GET /H")) {
          digitalWrite(LED, HIGH);               // GET /H turns the LED on
          Heltec.display -> drawString(0, 10, "Turn LED on");
          Heltec.display -> display();
        }
        if (currentLine.endsWith("GET /L")) {
          digitalWrite(LED, LOW);                // GET /L turns the LED off
          Heltec.display -> drawString(0, 10, "Turn LED off");
          Heltec.display -> display();
          
        }
      }
    }
    // close the connection:
    client.stop();
    Serial.println("Client Disconnected.");
  }
}

Referências

  1. ↑ https://community.hiveeyes.org/t/heltec-wifi-lora-32/3125

Evandro.cantu (discussão) 15h48min de 8 de fevereiro de 2022 (-03)

Disponível em “http://wiki.foz.ifpr.edu.br/wiki/index.php?title=ESP32:_Laboratorios&oldid=29419”