Example Code for Arduino-Period Measurement Mode

Before starting, configure the sampling rate and repeatability, then enter periodic mode. The sensor outputs temperature and humidity data to the serial port for 10 seconds, after which it exits periodic mode and switches to two measurement modes:

• Single Measurement Mode: Performs one-time readings for comparison.

• Cycle Measurement Mode: Continuously monitors temperature and humidity.

The ALERT pin is active only in this mode.

Hardware Preparation

• DFRduino UNO R3 (or similar) x 1
• Gravity: SHT31-F Digital Temperature and Humidity Sensor x1
• Connectors

Software Preparation

• Arduino IDE
• Download and install the SHT3x Library and Example Programs. (About how to install the library?)

Wiring Diagram

Other Preparation Work

• Confirm the hardware IIC address matches the program's default address (0x45).
• Initialize the chip and check for successful communication.
• Set the measurement frequency (e.g., 1Hz in the code).

Sample Code

/*!
 * @file periodicDataReading.ino
 * @brief Read ambient temperature (C/F) and relative humidity (%RH) in cycle read mode.
 * @n Experimental phenomenon: Before we start, please set the read frequency and repeatability of the read
 * (the difference between the data measured by the chip under the same measurement conditions),
 * and enter the periodic read mode, and then read the temperature and humidity data.
 * @n The temperature and humidity data will be printed at the serial port, after 10 seconds of operation.
 * @n It will exit the cycle mode and enter 2 measurement mode: Single measurement mode and Cycle measurement mode.
 * @n Single measurement mode: reflect the difference between the two modes of reading data.
 * @n Cycle measurement mode: the chip periodically monitors temperature and humidity, only in this mode the ALERT pin will work.
 * @copyright  Copyright (c) 2010 DFRobot Co.Ltd (https://www.dfrobot.com)
 * @licence     The MIT License (MIT)
 * @author [fengli]([email protected])
 * @version  V1.0
 * @date  2019-08-20
 * @get from https://www.dfrobot.com
 * @url https://github.com/DFRobot/DFRobot_SHT3x
*/

#include <DFRobot_SHT3x.h>

/*!
 * @brief Construct the function
 * @param pWire IIC bus pointer object and construction device, can both pass or not pass parameters, Wire in default.
 * @param address Chip IIC address, two optional addresses 0x44 and 0x45(0x45 in default).
 * @param RST Chip reset pin, 4 in default.
 * @n The IIC address is determined by the pin addr on the chip.
 * @n When the ADR is connected to VDD, the chip IIC address is 0x45.
 * @n When the ADR is connected to GND, the chip IIC address is 0x44.
 */
//DFRobot_SHT3x sht3x(&Wire,/*address=*/0x45,/*RST=*/4);

DFRobot_SHT3x sht3x;

void setup() {

  Serial.begin(9600);
    //Initialize the chip to detect if it can communicate properly.
  while (sht3x.begin() != 0) {
    Serial.println("Failed to initialize the chip, please confirm the chip connection");
    delay(1000);
  }
  
  /**
   * readSerialNumber Read the serial number of the chip
   * @return Return 32-digit serial number
   */
  Serial.print("chip serial number: ");
  Serial.println(sht3x.readSerialNumber());
  /**
   * softReset Send command resets via IIC, enter the chip's default mode single-measure mode, 
   * turn off the heater, and clear the alert of the ALERT pin.
   * @return Read the status register to determine whether the command was executed successfully, 
   * and return true indicates success.
   */
   if(!sht3x.softReset()){
     Serial.println("Failed to reset the chip");
   }

  /**
   * pinReset Reset through the chip's reset pin, enter the chip's default mode single-measure mode, 
   * turn off the heater, and clear the alert of the ALERT pin.
   * @return The status register has a data bit that detects whether the chip has been reset, 
   * and return true indicates success.
   * @note When using this API, the reset pin of the chip nRESET should be connected to RST (default to pin4) of arduino.
   */
  //if(!sht3x.pinReset()){
    //Serial.println("Failed to reset the chip");
  //}

  /**
   * heaterEnable() Turn on the heater inside the chip so that the sensor can have accurate humidity data even in humid environment.
   * @return Read the status register to determine whether the command was executed successfully, and return true indicates success.
   * @NOTE Heaters should be used in wet environment, and other cases of use will result in incorrect readings.
   */
  //if(!sht3x.heaterEnable()){
    // Serial.println("Failed to turn on the heater");
  //}
  /**
   * startPeriodicMode Enter cycle measurement mode and set repeatability and read frequency.
   * @param measureFreq Read the eMeasureFrequency_t data frequency.
   * @note  Selectable parameters:
               eMeasureFreq_Hz5,   /**the chip collects data in every 2s
               eMeasureFreq_1Hz,   /**the chip collects data in every 1s 
               eMeasureFreq_2Hz,   /**the chip collects data in every 0.5s 
               eMeasureFreq_4Hz,   /**the chip collects data in every 0.25s 
               eMeasureFreq_10Hz   /**the chip collects data in every 0.1s 
   * @param repeatability Read the repeatability of temperature and humidity data, the default parameter is eRepeatability_High.
   * @note  Optional parameters:
               eRepeatability_High /**In high repeatability mode, the humidity repeatability is 0.10%RH, the temperature repeatability is 0.06°C
               eRepeatability_Medium,/**In medium repeatability mode, the humidity repeatability is 0.15%RH, the temperature repeatability is 0.12°C.
               eRepeatability_Low, /**In low repeatability mode, the humidity repeatability is0.25%RH, the temperature repeatability is 0.24°C
   * @return Read the status of the register to determine whether the command was executed successfully, and return true indicates success
   */          
  if(!sht3x.startPeriodicMode(sht3x.eMeasureFreq_1Hz)){
    Serial.println("Failed to enter the periodic mode");
  }
  Serial.println("------------------Read data in cycle measurement mode-----------------------");
}

void loop() {

  Serial.print("Ambient temperature(°C/F):");
  /**
   * getTemperatureC Get the measured temperature (in degrees Celsius).
   * @return Return the float temperature data.
   */
  Serial.print(sht3x.getTemperatureC());
  Serial.print(" C/");
  /**
   * getTemperatureF Get the measured temperature (in degrees Fahrenheit).
   * @return Return the float temperature data. 
   */
  Serial.print(sht3x.getTemperatureF());
  Serial.print(" F ");
  Serial.print("Relative humidity(%RH):");
  /**
   * getHumidityRH Get measured humidity(%RH)
   * @return Return the float humidity data
   */
  Serial.print(sht3x.getHumidityRH());
  Serial.println(" %RH");
  //Please adjust the frequency of reading according to the frequency of the chip collection data.
  //The frequency to read data must be greater than the frequency to collect the data, otherwise the returned data will go wrong.
  delay(100);
  if(millis() > 10000 && millis() < 10200){
    /**
     * stopPeriodicMode() Exit from the cycle read data
     * @return Read the status of the register to determine whether the command was executed successfully, 
     * and return true indicates success.
     */
    sht3x.stopPeriodicMode();
    Serial.println("Exited from the cycle measurement mode, enter the single measurement mode");
  }
  /**
   * readTemperatureAndHumidity Get temperature and humidity data in cycle measurement mode and use structures to receive data
   * @return Return a structure containing celsius temperature (°C), Fahrenheit temperature (°F), relative humidity (%RH), status code.
   * @n A status of 0 indicates that the right return data.
   
  DFRobot_SHT3x::sRHAndTemp_t data = sht3x.readTemperatureAndHumidity();
  if(data.ERR == 0){
    Serial.print("ambient temperature(°C/F):");
    Serial.print(data.TemperatureC);
    Serial.print("C/");
    Serial.print(data.TemperatureF);
    Serial.print("F");
    Serial.print("relative humidity(%RH):");
    Serial.print(data.Humidity);
    Serial.println("%RH");
  }
  */
}

Result

Serial print the temperature and humidity information in period measurement mode for 10s, then exit from this mode and enter single measurement mode, and print the information.

Additional Information

• The code automatically exits periodic mode after 10 seconds and returns to single measurement mode.
• Measurement frequency must be less than the reading frequency to avoid data errors.