NEW: Temp & Humidity Sensor

Adafruit HTU21D-F

NewImage346New York City NY, USA?? –?? It???s summer and you???re sweating and your hair???s all frizzy and all you really want to know is why the weatherman said this morning that today???s relative humidity would max out at a perfectly reasonable 52% when it feels more like 77%.

Enter the HTU21D-F Temperature + Humidity Sensor, the best way to prove the weatherman wrong!

This I2C digital humidity sensor is an accurate and intelligent alternative to the much simpler Humidity and Temperature Sensor ??? SHT15 Breakout.

It has a typical accuracy of ??2% with an operating range that???s optimized from 5% to 95% RH.

Operation outside this range is still possible ??? just the accuracy might drop a bit. The temperature output has an accuracy of ??1 ??C from -30 to +90 ??C.

If you???re looking to measure temperature more accurately, we recommend the MCP9808 High Accuracy I2C Temperature Sensor Breakout Board.

Such a lovely chip! So, we spun up a breakout board that includes the Filtered version (the white bit of plastic which is a PTFE filter to keep the sensor clean), a 3.3 VDC regulator and I2C level shifting circuitry.

This lets you use it safely with any kind of microcontroller with 3.3 – 5 VDC power or logic. Each order comes with one fully assembled and tested PCB breakout and a small piece of header.

  • You???ll need to solder the header onto the PCB but it???s fairly easy and takes only a few minutes even for a beginner.
  • It???s also very easy to use, thanks to our Arduino library. Simply wire up the Vin pin to 3-5 VDC, GND pin to power/logic ground, SDA to your microcontroller???s I2C data line and SCL to the I2C clock line.
  • Then download and install the Adafruit HTU21DF library.
  • Restart the IDE and launch the HTU21DFtest example to see temperature and humidity printed out.

If you???re not using Arduino it???s really easy to port the library, as well.

More details online at:

Adafruit was founded in 2005 by MIT engineer, Limor “Ladyada” Fried. Her goal was to create the best place online for learning electronics and making the best designed products for makers of all ages and skill levels. Adafruit has grown to over 50 employees in the heart of NYC with a 15,000+ sq ft. factory. Adafruit has expanded offerings to include tools, equipment and electronics that Limor personally selects, tests and approves before going in to the Adafruit store. Limor was the first female engineer on the cover of WIRED magazine and was recently awarded Entrepreneur magazine’s Entrepreneur of the year.

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