By default the HTU21D sets the temperature and humidity sensor resolutions are set at their highest. These default values are, humidity = 12bit and temperature = 14bit. This is all well and good for most situations when you are trying to get the best performance from your device. However, a higher resolution comes at the expense of increased measuring time. Consequently, a longer measuring time will increase the current consumption too.
To demonstrate, I’ve tabulated the maximum measuring times for the different sensor resolution modes from the HTU21D_datasheet.
Having both temperature and humidity sensor capabilities in a single package makes the HTU21D an ideal sensor for a home weather station. As such, if you’re a person who is interested in knowing the current weather conditions, you’ll probably want to know what the Dew Point is too. But before we can get carried away, we need to learn how to use an additional library.
This tutorial will show you how to interface your Arduino to a HTU21D humidity and temperature sensor and start taking measurements. Once you’ve got the basics, we’ll take a look at configuring the sensor to optimise its performance. What you’ll need:
- An Arduino or compatible clone
- A HTU21D temperature sensor. I’ll be using one of these from Adafruit.
- Jumper wires