Introduction

The module integrates Si7021 Humidity and Temperature sensor. The sensor is a monolithic CMOS IC integrating humidity and temperature sensor elements, an analog-to-digital converter, signal processing, calibration data, and an I2C Interface. It is low drift and hysteresis, and excellent long term stability.

Applications

Specifications

PINOUT

Si7021_pin.png

Soldering pad with 2.5mm spacing:

Gadgeteer Socket:"I" x2

Connection Diagram

Si7021_connect.png

Sample Code


#include <Wire.h>

const int ADDR =0x40;
int X0,X1,Y0,Y1,Y2,Y3;
double X,Y,X_out,Y_out1,Y_out2;

void setup()
{
  Serial.begin(9600);
  Wire.begin();
  delay(100);
  Wire.beginTransmission(ADDR);
  Wire.endTransmission();
  pinMode(13,OUTPUT);
}
void loop()
{
  /**Send command of initiating temperature measurement**/
  Wire.beginTransmission(ADDR);
  Wire.write(0xE3);
  Wire.endTransmission();

  Serial.print("Temp");
  Serial.print("\t");
  Serial.println("RH");

  /**Read data of temperature**/
  digitalWrite(13,HIGH);
  Wire.requestFrom(ADDR,2);

  if(Wire.available()<=2);
  {
    X0 = Wire.read();
    X1 = Wire.read();
    X0 = X0<<8;
    X_out = X0+X1;
  }

  /**Calculate and display temperature**/
  X=(175.72*X_out)/65536;
  X=X-46.85;
  Serial.print(X);
  Serial.print("C");
  Serial.print("\t");

  /**Send command of initiating relative humidity measurement**/
  Wire.beginTransmission(ADDR);
  Wire.write(0xE5);
  Wire.endTransmission();

  /**Read data of relative humidity**/
  Wire.requestFrom(ADDR,2);
  if(Wire.available()<=2);
  {
    Y0 = Wire.read();
    Y2=Y0/100;
    Y0=Y0%100;
    Y1 = Wire.read();
    Y_out1 = Y2*25600;
    Y_out2 = Y0*256+Y1;
  }

  /**Calculate and display relative humidity**/
  Y_out1 = (125*Y_out1)/65536;
  Y_out2 = (125*Y_out2)/65536;
  Y = Y_out1+Y_out2;
  Y=Y-6;
  Serial.print(Y);
  Serial.println("%");

  digitalWrite(13,LOW);
  delay(300);
}

TOY0054_exampleresult.png

DFshopping_car1.png Get SI7021 Temperature and humidity sensor(SKU: TOY0054) from DFRobot Store or DFRobot Distributor.

category: Product Manual category: SEN Series category: Sensors

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