The DHT11 is a 4-pin (one pin is unused) temperature and humidity sensor capable of measuring 20% – 90% relative humidity and 0 to 50 °C. The sensor can operate between 3 and 5.5V DC and communicates using its own proprietary OneWire protocol. This protocol requires very precise timing in order to get the data from the sensor. The LOW and HIGH bits are coded on the wire by the length of time the signal is HIGH. The total time to take a reading is at most 23.4 ms. This includes an 18 ms delay required to start the data transfer and a window of up to 5.4 ms for the data. Individual signals can be as short as 20 μs and as long as 80 μs.
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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, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, 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.