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!
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 3.3V regulator and I2C level shifting circuitry. This lets you use it safely with any kind of microcontroller with 3.3V-5V 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 3-5VDC, 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.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.