How to Use Heltec Lora 32 v2: Examples, Pinouts, and Specs

The Heltec LoRa 32 v2 is a compact development board designed for IoT applications. It features an ESP32 microcontroller with integrated LoRa (Long Range) communication capabilities, making it ideal for projects requiring low power consumption and long-distance wireless connectivity. The board also includes an onboard OLED display, Wi-Fi, and Bluetooth, providing a versatile platform for a wide range of applications.

• IoT (Internet of Things) devices and networks
• Remote environmental monitoring
• Smart agriculture and precision farming
• Asset tracking and logistics
• Home automation systems
• Long-range wireless sensor networks

The Heltec LoRa 32 v2 combines powerful processing capabilities with advanced communication features. Below are the key technical details:

The Heltec LoRa 32 v2 has a total of 26 GPIO pins, along with other dedicated pins for power, communication, and peripherals. Below is the pinout description:

1. Powering the Board:

   • Connect the board to a 5V USB power source or use a 3.7V LiPo battery via the JST connector.
   • Ensure the power source provides sufficient current (at least 500 mA).

2. Programming the Board:

   • Install the Arduino IDE and add the ESP32 board support package.
   • Select "Heltec ESP32 LoRa" as the board type in the Arduino IDE.
   • Connect the board to your computer via a USB cable and upload your code.

3. Connecting Peripherals:

   • Use the GPIO pins to connect sensors, actuators, or other peripherals.
   • For I2C devices, connect them to GPIO21 (SDA) and GPIO22 (SCL).
   • For SPI devices, use GPIO18 (SCK), GPIO19 (MISO), and GPIO23 (MOSI).

4. Using the LoRa Module:

   • Install the "LoRa" library in the Arduino IDE.
   • Configure the frequency band (433 MHz, 868 MHz, or 915 MHz) based on your region.
   • Use the LoRa library functions to send and receive data.

5. Using the OLED Display:

   • Install the "Heltec ESP32" library in the Arduino IDE.
   • Use the library functions to display text, graphics, or sensor data on the OLED.

Below is an example of how to send a message using the LoRa module and display it on the OLED:

#include <Wire.h>
#include <LoRa.h>
#include <heltec.h>

// Define LoRa parameters
#define LORA_BAND 915E6  // Set frequency to 915 MHz (adjust for your region)

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  while (!Serial);

  // Initialize Heltec board
  Heltec.begin(true /* Display */, true /* LoRa */, true /* Serial */);

  // Initialize LoRa module
  if (!LoRa.begin(LORA_BAND)) {
    Serial.println("LoRa initialization failed!");
    while (1);
  }
  Serial.println("LoRa initialized successfully!");

  // Display initialization message on OLED
  Heltec.display->clear();
  Heltec.display->drawString(0, 0, "LoRa Ready!");
  Heltec.display->display();
}

void loop() {
  // Send a message via LoRa
  LoRa.beginPacket();
  LoRa.print("Hello, LoRa!");
  LoRa.endPacket();

  // Display message on OLED
  Heltec.display->clear();
  Heltec.display->drawString(0, 0, "Message Sent:");
  Heltec.display->drawString(0, 16, "Hello, LoRa!");
  Heltec.display->display();

  // Wait 5 seconds before sending the next message
  delay(5000);
}

• Antenna Connection: Always connect the LoRa antenna before powering the board to avoid damage to the LoRa module.
• Frequency Compliance: Ensure the selected frequency band complies with local regulations.
• Power Supply: Use a stable power source to avoid unexpected resets or performance issues.
• Deep Sleep Mode: Utilize the deep sleep mode to reduce power consumption in battery-powered applications.

1. LoRa Module Not Initializing:

   • Ensure the correct frequency band is configured in the code.
   • Verify that the antenna is securely connected.

2. OLED Display Not Working:

   • Check the connections to GPIO25 (SDA) and GPIO26 (SCL).
   • Ensure the "Heltec ESP32" library is installed and included in your code.

3. Board Not Detected by Arduino IDE:

   • Install the correct USB driver for the CP2102 chip (used for USB-to-serial communication).
   • Verify that the correct COM port is selected in the Arduino IDE.

4. Frequent Resets or Instability:

   • Use a power source capable of supplying at least 500 mA.
   • Check for loose connections or short circuits.

Q: Can I use the Heltec LoRa 32 v2 with other LoRa devices?
A: Yes, the board is compatible with any device using the same LoRa frequency and protocol.

Q: What is the maximum range of the LoRa module?
A: The range depends on environmental factors but can reach up to 10 km in open areas.

Q: Can I power the board with a solar panel?
A: Yes, you can use a solar panel with a compatible LiPo battery and charge controller.

Q: Is the board compatible with MicroPython?
A: Yes, the Heltec LoRa 32 v2 supports MicroPython, but you need to flash the appropriate firmware.