How to Use LILYGO T-Higrow ESP32: Examples, Pinouts, and Specs

The LILYGO T-Higrow ESP32 is a versatile development board designed for Internet of Things (IoT) applications. It is powered by the ESP32 microcontroller, which features dual-core processing, built-in Wi-Fi, and Bluetooth capabilities. The T-Higrow board is equipped with various sensors, including a capacitive soil moisture sensor, temperature and humidity sensor, and a battery management system, making it ideal for environmental monitoring and smart agriculture projects.

• Smart agriculture and soil monitoring
• Environmental data logging
• IoT-based weather stations
• Home automation systems
• Educational projects and prototyping

The following table outlines the key technical details of the LILYGO T-Higrow ESP32:

The T-Higrow ESP32 features a compact pinout. Below is the pin configuration:

1. Powering the Board:

   • Connect a 3.7V LiPo battery to the battery connector, or power the board via the USB port (5V).
   • Ensure the battery is properly charged if using battery power.

2. Connecting Sensors:

   • The capacitive soil moisture sensor is pre-wired to GPIO4.
   • The DHT11 temperature and humidity sensor is integrated and does not require additional connections.

3. Programming the Board:

   • Use the Arduino IDE or ESP-IDF to program the ESP32.
   • Install the necessary ESP32 board definitions in the Arduino IDE.
   • Connect the board to your computer via USB and select the appropriate COM port.

4. Uploading Code:

   • Press and hold the "BOOT" button while clicking "Upload" in the Arduino IDE to enter programming mode.

• Power Supply: Always use a stable power source to avoid unexpected resets or malfunctions.
• Moisture Sensor: Avoid prolonged exposure of the soil moisture sensor to water to prevent corrosion.
• Battery Management: Use only compatible LiPo batteries to ensure safe operation.
• Wi-Fi and Bluetooth: Avoid using both Wi-Fi and Bluetooth simultaneously for power-sensitive applications.

Below is an example code snippet to read data from the soil moisture sensor and DHT11 sensor:

#include <DHT.h>

// Define pin connections
#define SOIL_MOISTURE_PIN 4  // GPIO4 for soil moisture sensor
#define DHT_PIN 5            // GPIO5 for DHT11 sensor
#define DHT_TYPE DHT11       // Define the type of DHT sensor

DHT dht(DHT_PIN, DHT_TYPE);

void setup() {
  Serial.begin(115200);  // Initialize serial communication
  dht.begin();           // Initialize DHT sensor
  pinMode(SOIL_MOISTURE_PIN, INPUT);  // Set soil moisture pin as input
}

void loop() {
  // Read soil moisture value
  int soilMoistureValue = analogRead(SOIL_MOISTURE_PIN);
  Serial.print("Soil Moisture: ");
  Serial.println(soilMoistureValue);

  // Read temperature and humidity
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Check if readings are valid
  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("Failed to read from DHT sensor!");
  } else {
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");
    Serial.print("Humidity: ");
    Serial.print(humidity);
    Serial.println(" %");
  }

  delay(2000);  // Wait 2 seconds before the next reading
}

1. Board Not Detected by Computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Verify that the correct COM port is selected in the Arduino IDE.

2. Failed to Upload Code:

   • Press and hold the "BOOT" button while uploading the code.
   • Check that the correct board and port are selected in the Arduino IDE.

3. Incorrect Sensor Readings:

   • Ensure the sensors are properly connected and not damaged.
   • Verify that the soil moisture sensor is not submerged in water for extended periods.

4. Wi-Fi Connection Issues:

   • Check the Wi-Fi credentials in your code.
   • Ensure the Wi-Fi network is within range and operational.

• Can I use the T-Higrow ESP32 with other IoT platforms?
  Yes, the board is compatible with platforms like Blynk, MQTT, and ThingSpeak.

• What is the maximum range of the Wi-Fi module?
  The ESP32's Wi-Fi range is approximately 30 meters indoors and 100 meters outdoors, depending on environmental factors.

• Can I power the board directly with a 5V power supply?
  Yes, you can power the board via the USB port using a 5V power supply.

• Is the board compatible with MicroPython?
  Yes, the T-Higrow ESP32 supports MicroPython in addition to the Arduino IDE and ESP-IDF.