How to Use HiLetGo ESP32-WROOM-32D: Examples, Pinouts, and Specs

The HiLetGo ESP32-WROOM-32D (Part ID: 3-01-1287) is a high-performance microcontroller module designed for IoT (Internet of Things) applications. It features integrated Wi-Fi and Bluetooth capabilities, a dual-core processor, and a wide range of GPIO pins, making it suitable for projects requiring wireless communication, real-time processing, and versatile interfacing.

• IoT devices and smart home automation
• Wireless sensor networks
• Robotics and real-time control systems
• Wearable devices
• Data logging and remote monitoring
• Prototyping and development of connected devices

The HiLetGo ESP32-WROOM-32D has 38 pins. Below is a summary of the key pins and their functions:

Note: Some GPIO pins have specific restrictions or dual functions. Refer to the ESP32 datasheet for detailed pin behavior.

1. Powering the Module:

   • Provide a stable 3.3V power supply to the 3V3 pin. Avoid exceeding the input voltage range (3.0V - 3.6V).
   • Connect the GND pin to the ground of your circuit.

2. Programming the Module:

   • Use a USB-to-Serial adapter to connect the ESP32 to your computer.
   • Connect the TX pin of the adapter to the RX0 pin (IO3) of the ESP32.
   • Connect the RX pin of the adapter to the TX0 pin (IO1) of the ESP32.
   • Use the EN pin to reset the module if needed.

3. Boot Mode Selection:

   • To upload code, hold the IO0 pin low (connect to GND) while resetting the module.

4. Connecting Peripherals:

   • Use GPIO pins for interfacing with sensors, actuators, and other devices.
   • For I2C communication, use IO21 (SDA) and IO22 (SCL).
   • For SPI communication, use IO18 (SCK), IO19 (MISO), and IO23 (MOSI).

• Voltage Levels: Ensure all connected peripherals operate at 3.3V logic levels to avoid damaging the module.
• Pin Multiplexing: Some pins have multiple functions (e.g., ADC, touch sensing). Configure them appropriately in your code.
• Antenna Placement: Avoid placing metal objects near the onboard antenna to ensure optimal Wi-Fi and Bluetooth performance.
• Heat Management: The module may heat up during operation. Ensure proper ventilation in your design.

Below is an example of how to blink an LED connected to GPIO2 of the ESP32 using the Arduino IDE:

// Example: Blink an LED on GPIO2 of the ESP32

// Define the GPIO pin for the LED
const int ledPin = 2;

void setup() {
  // Initialize the GPIO pin as an output
  pinMode(ledPin, OUTPUT);
}

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

  // Turn the LED off
  digitalWrite(ledPin, LOW);
  delay(1000); // Wait for 1 second
}

Note: Install the ESP32 board package in the Arduino IDE before uploading the code.

1. Module Not Detected by Computer:

   • Ensure the USB-to-Serial adapter is properly connected.
   • Install the correct USB driver for your adapter (e.g., CP2102 or CH340).

2. Code Upload Fails:

   • Check the boot mode. Hold the IO0 pin low during reset to enter programming mode.
   • Verify the correct COM port and board settings in the Arduino IDE.

3. Wi-Fi Connection Issues:

   • Ensure the correct SSID and password are used in your code.
   • Check for interference or weak signal strength near the module.

4. GPIO Pin Not Working:

   • Verify the pin configuration in your code.
   • Check if the pin is being used for another function (e.g., ADC, touch sensing).

• Q: Can the ESP32-WROOM-32D operate at 5V?
  A: No, the module operates at 3.3V. Use a level shifter for 5V peripherals.

• Q: How do I reset the module?
  A: Pull the EN pin low momentarily to reset the module.

• Q: Can I use the ESP32 with a battery?
  A: Yes, ensure the battery provides a stable 3.3V output.

• Q: What is the maximum Wi-Fi range?
  A: The range depends on environmental factors but typically extends up to 50 meters indoors and 200 meters outdoors.

For further assistance, refer to the official ESP32 datasheet or HiLetGo support resources.