How to Use ESP32-Wroom-HW-394: Examples, Pinouts, and Specs

The ESP32-Wroom-HW-394 is a powerful microcontroller module designed for IoT (Internet of Things) applications. It features integrated Wi-Fi and Bluetooth capabilities, making it ideal for wireless communication and smart device projects. With its dual-core processing power and a wide range of GPIO (General Purpose Input/Output) pins, the ESP32-Wroom-HW-394 is versatile and suitable for a variety of applications, including home automation, wearable devices, and industrial IoT systems.

• Smart home devices (e.g., smart lights, thermostats)
• Wireless sensor networks
• Industrial automation and monitoring
• Wearable technology
• Robotics and drones
• Real-time data logging and cloud integration

The ESP32-Wroom-HW-394 is packed with features that make it a robust and flexible choice for developers. Below are its key technical specifications:

The ESP32-Wroom-HW-394 has a total of 38 pins. Below is a table describing the key pins and their functions:

For a complete pinout, refer to the official datasheet.

1. Powering the Module:
   • Connect the 3V3 pin to a 3.3V power source.
   • Connect the GND pin to the ground of the power source.
2. Programming the Module:
   • Use a USB-to-Serial adapter to connect the module to your computer.
   • Connect the TXD0 pin to the RX pin of the adapter and the RXD0 pin to the TX pin of the adapter.
   • Use the EN pin to reset the module if needed.
3. Interfacing with Peripherals:
   • Use the GPIO pins for digital input/output.
   • Use ADC pins for analog input and DAC pins for analog output.
   • Use I2C, SPI, or UART for communication with other devices.

• Voltage Levels: Ensure all connected devices operate at 3.3V logic levels to avoid damaging the module.
• Deep Sleep Mode: Use deep sleep mode to conserve power in battery-powered applications.
• Antenna Placement: Ensure the onboard antenna has sufficient clearance from metal objects to avoid interference.
• Boot Mode: To enter bootloader mode, hold GPIO0 low while resetting the module.

The ESP32-Wroom-HW-394 can be programmed using the Arduino IDE. Below is an example of how to connect the module to Wi-Fi and blink an LED:

#include <WiFi.h> // Include the WiFi library for ESP32

const char* ssid = "Your_SSID";       // Replace with your Wi-Fi network name
const char* password = "Your_Password"; // Replace with your Wi-Fi password
const int ledPin = 2;                 // GPIO2 is connected to the onboard LED

void setup() {
  Serial.begin(115200);               // Initialize serial communication
  pinMode(ledPin, OUTPUT);            // Set GPIO2 as an output pin

  // Connect to Wi-Fi
  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi connected!");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());     // Print the module's IP address
}

void loop() {
  digitalWrite(ledPin, HIGH);         // Turn the LED on
  delay(1000);                        // Wait for 1 second
  digitalWrite(ledPin, LOW);          // Turn the LED off
  delay(1000);                        // Wait for 1 second
}

1. Module Not Connecting to Wi-Fi:

   • Ensure the SSID and password are correct.
   • Check if the Wi-Fi network is within range.
   • Verify that the module's antenna is not obstructed.

2. Module Not Responding:

   • Check the power supply voltage (must be 3.3V).
   • Ensure the EN pin is pulled high.
   • Verify the connections to the USB-to-Serial adapter.

3. GPIO Pins Not Working:

   • Ensure the pins are not being used for other functions (e.g., boot mode).
   • Check for short circuits or incorrect wiring.

Q: Can the ESP32-Wroom-HW-394 operate on 5V?
A: No, the module operates at 3.3V. Using 5V can damage the module.

Q: How do I update the firmware?
A: Use the ESP32 Flash Download Tool or the Arduino IDE to upload new firmware.

Q: Can I use the ESP32-Wroom-HW-394 with a battery?
A: Yes, you can use a 3.7V LiPo battery with a voltage regulator to provide 3.3V to the module.

Q: What is the maximum range of the Wi-Fi?
A: The Wi-Fi range is approximately 50 meters indoors and 200 meters outdoors, depending on the environment.