DHT22 temperature and humidity sensor - without circuit board, 3.3-5.5 V

Product overview

• Digital combined sensor for temperature and relative humidity
• Bare sensor without a carrier board, with four pins in a row
• Proprietary digital one-wire interface, not compatible with the Dallas bus or I²C
• External pull-up resistor required
• Operating voltage 3.3 to 5.5 V
• Measurement range: temperature −40 to 80 °C, humidity 0 to 99.9% RH

Product description

This combined sensor measures temperature and relative humidity simultaneously using a capacitive humidity element and a thermistor. The readings are processed digitally and output via a one-wire interface, so no analog-to-digital converter is needed.

Communication uses a proprietary protocol that is not compatible with the Dallas standard. The microcontroller briefly pulls the data line low, after which the sensor sends back a data packet containing humidity and temperature readings as well as a checksum.

Since the sensor is supplied without a carrier board, it lacks the pull-up resistor usually found on breakout modules. An external pull-up resistor must be added between the data line and the supply voltage. Only three of the four pins are used: supply voltage, ground, and data line.

The sensor is used in weather stations, for indoor climate monitoring, or in data loggers where temperature and humidity are measured simultaneously. Its operating voltage of 3.3 to 5.5 V makes it compatible with various microcontroller platforms. Libraries for common development environments support the one-wire protocol; depending on the board used, minor adjustments to the control may be necessary.

Safety notice

An external pull-up resistor on the data line is required for reliable operation. The sensor is intended exclusively for building prototypes and for testing and development purposes, and is not suitable for installation in household electrical circuits.

Package contents

• 1x DHT22 temperature and humidity sensor (without breakout board)