Arduino Due and HTU21 sensor example

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The HTU21D(F) is a new digital humidity sensor with temperature output by MEAS. Setting new standards in terms of size and intelligence, it is embedded in a reflow solderable Dual Flat No leads (DFN) package with a small 3 x 3 x 0.9 mm footprint. This sensor provides calibrated, linearized signals in digital, I²C format. HTU21D(F) digital humidity sensors are dedicated humidity and temperature plug and play transducers for OEM applications where reliable and accurate measurements are needed. Direct interface with a micro-controller is made possible with the module for humidity and temperature digital outputs. These low power sensors are designed for high volume and cost sensitive applications with tight space constraints.

Every sensor is individually calibrated and tested. Lot identification is printed on the sensor and an electronic identification code is stored on the chip – which can be read out by command. Low battery can be detected and a checksum improves communication reliability.

 

Schematic

 

Code

This example uses the https://github.com/adafruit/Adafruit_HTU21DF_Library

#include <Wire.h>
#include "Adafruit_HTU21DF.h"
 
// Connect Vin to 3-5VDC
// Connect GND to ground
// Connect SCL to I2C clock pin (A5 on UNO)
// Connect SDA to I2C data pin (A4 on UNO)
 
Adafruit_HTU21DF htu = Adafruit_HTU21DF();
 
void setup() {
  Serial.begin(9600);
  Serial.println("HTU21D-F test");
 
  if (!htu.begin()) {
    Serial.println("Couldn't find sensor!");
    while (1);
  }
}
 
 
void loop() {
  Serial.print("Temp: ");
  Serial.print(htu.readTemperature());
  Serial.print("\t\tHum: ");
  Serial.println(htu.readHumidity());
  delay(500);
}

 

Links

Humidity Sensor – HTU21 Breakout Board GY-21

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