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Humidity and temperature sensor Si7020

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About Si7020


A Humidity and temperature sensor Si7020  has developed using monolithic CMOS technology. It is integrated with humidity and temperature sensing elements. Along with this, it has an analog-to-digital converter, signal processing, calibration data element. It operates on I2C protocol using I2c interface.The Si7020 offers an accurate, low-power, factory-calibrated digital solution ideal for measuring humidity, dewpoint, and temperature, in a number of industrial and other consumer applications.


The low-K polymeric dielectrics are used for sensing humidity . It allows the construction of low-power, monolithic CMOS Sensor ICs. It has low drift and hysteresis with excellent long term stability. The data obtained by factory calibrated Humidity and temperature sensors is stored on an on-chip non-volatile memory unit, is to assure that the sensors need not to be calibrated again and no changes are required at software end when they are interchanged.  This I2c module is powered up by 5V DC and it has on-board power regulation circuitry.This plug and play sensor eliminated the use of soldering and  is suitable for for connecting multiple I2C devices on the I2c bus.


This is a general purpose I²C device which is compatible with all computing platforms, such as Raspberry Pi, Beaglebone, Arduino, Particle, BridgeX5, and many more.


We will be demonstrating its interfacing with Raspberry Pi.The hardware hookup to bring this sensing module in use is mentioned below:

The hardware hookup states the wiring connections required between the sensor and the raspberry pi. Ensuring correct connections is the basic necessity while working on any system for the desired output. So, the requisite connections are as follows:

  • The Si7020 will work over I2C . Take a I2C shield for Raspberry pi and connect it on to  the gpio pins of Raspberry Pi.
  • Connect the one end of I2C cable to the in-port Si7020 sensor and the other end to the I2C shield.
  • Also connect the Ethernet cable to Raspberry Pi .Wi-Fi router can also be used for the same.
  • Power the Raspberry Pi using a Micro USB adapter


Communicating using I2C Protocol:


To make Raspberry Pi I2C enabled, proceed as mentioned below:

  • In terminal, type the following command to open the configuration settings:
    sudo raspi-config
  • Select “Advanced Options” in here.
  • Select “I2C” and Click “Yes”.
  • Reboot the system to set it up as per the changes made using the command reboot.


Programming the module:


The reward of using Raspberry Pi is, that is provides you the flexibility to opt a the programming language in which you want to program to interface the sensing device with Raspberry Pi. Harnessing this advantage of Raspberry Pi, we are demonstrating here its programming in the Java.


To set up the Java environment, Install the “pi4j libraby” from http://pi4j.com/install.html. Pi4j is a Java Input/Output Library for Raspberry Pi.
An easy and most preferred method to install the “pi4j library” is to execute the undermentioned command directly in your Raspberry Pi:

curl -s get.pi4j.com | sudo bash
curl -s get.pi4j.com


Some sample codes for Si7020 can be downloaded from our github community that is Control Everything Community.Links are as below:








It is majoring used in the areas such as respiratory therapy, defogging, in mobile phones and tablets,white goods,at indoor weather stations, for tacking asset/goods, and for monitoring the data at micro-environments/data center.


For more detailed information, refer to the link given here.

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