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Wiring

Let's begin by exploring the DHT22 sensor module. This module can sense temperature and humidity. In general, the DHT22 has four pins. You can see the sensor pinout in Figure 2-3:

Figure 2-3: A general pinout for a DHT22 sensor module

For our demo, we need to wire the hardware as follows:

Connect DHT22 pin 1 to the ESP32 board 3.3V.
Connect DHT22 pin 2 to the ESP32 board GPIO 26 (IO26). You can add a pull resistor 4K7 (optional).
Connect DHT22 pin 4 to the ESP32 board GND. You can add a pull resistor 4K7 (optional).

You can see my hardware wiring with the ESP-WROVER-KIT board and DHT22 in Figure 2-4:

Figure 2-4: A wiring sample from my hardware

Now that we have covered hardware wiring, let's move on to writing the program.