DHT22 Digital Temperature and Humidity Sensor | Pro Tronix

Product Description

The standalone, high-precision DHT22 (AM2302) sensor is a premium digital temperature and relative humidity transmitter, designed for environmental tracking in professional HVAC, greenhouse, and smart meteorological projects. Unlike pre-mounted modules, this bare 4-pin sensor package is tailored for custom PCB integration, compact spatial enclosures, and direct system engineering. Inside its durable white grid-vented polymer shell sits a capacitive moisture sensing element and a high-accuracy NTC thermistor, fully paired with a custom 8-bit digital processing core. By outputting calibrated, noise-resistant single-bus data, this sensor ensures highly accurate readings even over transmission distances up to 20 meters, making it the perfect component for custom industrial IoT nodes and micro-climate loggers.

Pinout / Layout Connections

The bare sensor package exposes 4 metallic pin terminals (spaced at a standard 2.54mm pitch):

• • Pin 1 (VDD): Main power supply input. Accepts a stable DC +3.3V to +5.5V.

  • Pin 2 (SDA): Bidirectional single-wire digital data bus. Connects directly to a digital microcontroller I/O pin.

  • Crucial Setup: A $4.7\text{ k}\Omega$ to $10\text{ k}\Omega$ pull-up resistor must be connected between Pin 2 (SDA) and Pin 1 (VDD) to maintain correct logic levels on bare sensor lines.

  • Pin 3 (NC): No Connection. Leave completely open/unconnected.

  • Pin 4 (GND): Connects to the common system ground (0V) reference.