Nos descargamos la última versión de Arduino IDE, tiene que ser por encima de la 1.6

Descargamos un plugin para poder conectar con esp32:

https://github.com/espressif/arduino-esp32

https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/boards_manager.md

Ponemos esta URL en file > preferences > Additional Boards Manager URLs:

https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_dev_index.json

Ahora vamos a tools > Board: “Arduino Uno” y seleccionamos Boards Manager. Buscamos esp32 y damos a install

En Tools > Board: “Arduino Uno” > ESP32 Arduino

Reiniciamos Arduino. Nos aseguramos que python apunte a python3 instalando python-is-python3

sudo apt install python-is-python3

Código de ejemplo. Conecta a wifi y nos da la ip. Una vez subido tenemos que reiniciar esp32 (desconectando usb)

#include <WiFi.h>        // Include the Wi-Fi library

const char* ssid     = "pitufina";         // The SSID (name) of the Wi-Fi network you want to connect to
const char* password = "reyvisigodo";     // The password of the Wi-Fi network

void setup() {
  Serial.begin(115200);         // Start the Serial communication to send messages to the computer
  delay(10);
  Serial.println('\n');
  
  WiFi.begin(ssid, password);             // Connect to the network
  Serial.print("Connecting to ");
  Serial.print(ssid);

  while (WiFi.status() != WL_CONNECTED) { // Wait for the Wi-Fi to connect
    delay(500);
    Serial.print('.');
  }

  Serial.println('\n');
  Serial.println("Connection established!");  
  Serial.print("IP address:\t");
  Serial.println(WiFi.localIP());         // Send the IP address of the ESP8266 to the computer
}

void loop() { 
  
}

La salida que nos da es esta:

.

Connection established!
IP address:	192.168.1.97

HAcer petición GET y POST

#include <WiFi.h>        // Include the Wi-Fi library
#include <HTTPClient.h>

const char* ssid     = "mi_red";         // The SSID (name) of the Wi-Fi network you want to connect to
const char* password = "*********";     // The password of the Wi-Fi network

//Your Domain name with URL path or IP address with path
String serverName = "http://192.168.1.200/esp32";

// the following variables are unsigned longs because the time, measured in
// milliseconds, will quickly become a bigger number than can be stored in an int.
unsigned long lastTime = 0;
// Timer set to 10 minutes (600000)
//unsigned long timerDelay = 600000;
// Set timer to 5 seconds (5000)
unsigned long timerDelay = 5000;

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

  WiFi.begin(ssid, password);
  Serial.println("Connecting");
  while(WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to WiFi network with IP Address: ");
  Serial.println(WiFi.localIP());
 
  Serial.println("Timer set to 5 seconds (timerDelay variable), it will take 5 seconds before publishing the first reading.");
}

void loop() {
  //Send an HTTP POST request every 10 minutes
  if ((millis() - lastTime) > timerDelay) {
    //Check WiFi connection status
    if(WiFi.status()== WL_CONNECTED){
      HTTPClient http;

      String serverPath = serverName + "?temperature=24.37";
      
      // Your Domain name with URL path or IP address with path
      http.begin(serverPath.c_str());
      
      // Send HTTP GET request
      int httpResponseCode = http.GET();
      
      if (httpResponseCode>0) {
        Serial.print("HTTP Response code: ");
        Serial.println(httpResponseCode);
        String payload = http.getString();
        Serial.println(payload);
      }
      else {
        Serial.print("Error code: ");
        Serial.println(httpResponseCode);
      }
      // Free resources
      http.end();
    }
    else {
      Serial.println("WiFi Disconnected");
    }
    lastTime = millis();
  }
}

https://www.youtube.com/watch?v=fs10aqFTj8I

apt-get install esptool

Descargamos el firmware:

https://micropython.org/download/esp32/

Descargo este:

 GENERIC : esp32-idf3-20210202-v1.14.bin 

Para borrar la memoria. Si no sabemos el puerto, no lo ponemos y lo detecta, es /dev/ttyUSB0:

esptool erase_flash

esptool.py v2.8
Found 1 serial ports
Serial port /dev/ttyUSB0
Connecting........_
Detecting chip type... ESP32
Chip is ESP32D0WDQ6 (revision 1)
Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None
Crystal is 40MHz
MAC: f0:08:d1:d3:1e:98
Enabling default SPI flash mode...
Erasing flash (this may take a while)...

A fatal error occurred: ESP32 ROM does not support function erase_flash.

Da error. Subimos el firmware que hemos descargado. Tarda un poco. Debería devolver un prompt pero no hace nada:

esptool write_flash 0x1000 esp32-idf3-20210202-v1.14.bin 

esptool.py v2.8
Found 1 serial ports
Serial port /dev/ttyUSB0
Connecting.......
Detecting chip type... ESP32
Chip is ESP32D0WDQ6 (revision 1)
Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None
Crystal is 40MHz
MAC: f0:08:d1:d3:1e:98
Enabling default SPI flash mode...
Configuring flash size...
Auto-detected Flash size: 4MB
Erasing flash...
Took 2.39s to erase flash block
Wrote 1445888 bytes at 0x00001000 in 140.5 seconds (82.3 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...

https://github.com/espressif/arduino-esp32

https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/boards_manager.md

Ponemos esta URL en file > preferences > Additional Boards Manager URLs:

https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_dev_index.json

Ahora vamos a tools > Board: “Arduino Uno” y seleccionamos Boards Manager. Buscamos esp32 y damos a install

En Tools > Board: “Arduino Uno” > ESP32 Arduino

https://lastminuteengineers.com/esp32-sleep-modes-power-consumption/