The Si7005 temperature and relative humidity sensor breakout boards are back in stock at Tindie. The Si7005 integrates fully factory-calibrated humidity and temperature sensor elements with an analog to digital converter, signal processing and an I2C host interface in a single monolithic CMOS sensor IC.
Si7005 breakout board
- Precise temperature and relative humidity measurements
- Standard I2C communication
- 0-100% RH range
- Excellent sensor stability
Check out Arduino Example.
The Si7005 is a digital relative humidity and temperature sensor from Silicon Labs. It integrates fully factory-calibrated humidity and temperature sensor elements with an analog to digital converter, signal processing and an I2C host interface in a single monolithic CMOS sensor IC. The Si7005 is available in a “non hand-assembly-friendly” 4×4 mm QFN package, which requires reflow soldering to mount it on a PCB. This breadboard friendly breakout board is designed to make your prototype project with the Si7005 sensor much easier. It can be used with PIC, Arduino, or any other microcontroller development platform through an I2C bus. The power supply and I2C signal pins are accessible through breadboard friendly 0.1″ pitch header pins. Note that the Si7005 sensor is not 5.0V tolerant. It must be operated at 2.1-3.6V power supply.
Si7005 breakout board
A couple weeks ago I received some sample products from Dorji Applied Technologies, a china-based company that make varieties of RF and sensor modules. One of the products I received was their latest DSTH01 sensor module that carries Silicon Labs’ Si7005 digital relative humidity and temperature sensor on board. Things I liked about it are it is inexpensive (available on Tindie for only $6), compact, and most importantly it supports I2C host interface for communication.
DSTH01 module with Si7005 sensor onboard
Pin diagrams of DSTH01 sensor module
The accuracy of most of the current IC temperature sensors is about ±1°C at room temperature. However, at hot and cold temperatures, the uncertainty increases exponentially, resulting in a parabolic-shaped error curve. This application note describes a technique to enhance the accuracy of the sensor by modeling the error curve and use it to compensate for the sensor drift at a wide range of operating temperature. A PIC MCU is used to compute the equation for the curve and apply it to the sensor output to provide a more accurate temperature reading.
Temperature sensor accuracy improvement
MCP9802 is a digital temperature sensor from Microchip that measures temperatures between -55°C and +125°C to a digital word. It provides an accuracy of ±1°C (maximum) from -10°C to +85°C. The MCP9802 sensor comes with user-programmable registers that provide flexibility for temperature sensing applications. The register settings also allow user-selectable 9-bit to 12-bit temperature measurement resolution. This sensor has an industry standard 2-wire I2C compatible serial interface, allowing up to eight devices to be controlled in a single serial bus. In this blog post I am going to write about an Arduino sketch to interface the MCP9802 sensor with an Arduino for temperature sensing application. For illustration, I am using the MCP9802 sensor onboard the I2C EEPROM+Sensor breakout board.
Arduino and MCP9802