The appearance of the Arduino UNO, back in the 2010 time frame, really changed the landscape of easily programmable microcontrollers. The associated Arduino IDE, along with numerous libraries that were being published, made writing and uploading programs much easier (by a lot) than previously possible. Attaching various sensors, to measure things like pressure or acceleration, suddenly became very accessible.
When it came to measuring humidity, the DHT11 and DHT22 sensors dominated the market. These were super cheap, readily available, and had ready-to-go Arduino libraries. Tons of guides were published using these sensors as demos.
Fast forward to now. The microcontroller market has evolved significantly. While you can still buy an Arduino UNO, there are now much more powerful options available. Even powerful enough to allow running an interpretive language like CircuitPython. Also, single board computers, like the Raspberry Pi, which run a full Linux operating system, provide a totally different class of host controllers.
In this modern landscape, are the DHT11/22 still good cheap choices for measuring humidity? The answer is NO. In this guide we go into why that is by briefly looking at how the DHT11/22 sensors work. We then provide some information on modern alternatives that should generally be used instead of the DHT11/22.
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