Description: The Si7021 is a low-cost, easy-to-use, highly accurate, digital humidity and temperature sensor. This sensor is ideal for environmental sensing and data logging and perfect for build a weather stations or humidor control system. All you need are two lines for I2C communication, and you’ll have relative humidity readings and very accurate temperature readings as a bonus!
There are only four pins that need to be hooked up in order to start using this sensor in a project. One for VCC, one for GND, and two data lines for I2C communication. This breakout board has built-in 4.7KΩ pullup resistors for I2C communications. If you’re hooking up multiple I2C devices on the same bus, you may want to disable these resistors.
Dimensions: 0.6" x 0.6"
Based on 5 ratings:
2 of 2 found this helpful:
Very easy setup, controlled by a Raspberry Pi 2 with CE’s Python script for this module: https://github.com/ControlEverythingCommunity/SI7021/blob/master/Python/SI7021.py
Highly recommended for temp and humidity in one package.
2 of 2 found this helpful:
This hooked up to the weather station I built easily. Just pulled in the libraries, added a few calls and cal factors and my station now has humidity and dew point stats. Weather Underground quality checkers gave my homemade station the gold seal once I added this sensor. Easy to use and reports accurately.
I spent 20 minutes (figuratively) pulling out my hair trying to get this thing connected to my Arduino. Then I realized: I had not physically connected all four jumper wires!
In all seriousness, this sensor works very well and I have had no real problems with it. It’s connected to my ESP8266 Thing Dev Board for logging data to ThingSpeak.
Got it working quickly, integrated it into a wireless outdoor reporting station. Sits next to a DHT-11 that quit measuring humidity in a matter of weeks after deployment (the second DHT-11 to fail quickly – a DHT-22 (less precise) lasted a year or so in the same place). I’m hoping that the PTFE cover over the Si7021 helps it survive a long time in our tough environment - it has to survive pollen and 100% humidity and sprinkler mist here in Florida.
The only negative was mounting. I soldered header pins with the short side on the sensor side, then trimmed them further, drilled a small hole in the plastic case for the sensor to protrude into (recessed just below the outer surface), and mounted it with the sensor into the hole and just put a big piece of tape over the board to hold it in position. The case is mounted with the sensor facing down to protect it from dust and droplets. I might hot-glue some sort of screen over it to keep bugs out, but it’s ok for now. We’ll see how long it lasts.
I have several of these boards. They just work, first time every time. I2C communication is simple and reliable.