DHT11 Humidity and Temperature Sensor Module

Description

Measure your surrounding air temperature and relative humidity with this conveniently sized sensor. Suitable for weather stations, home environmental systems, terrariums, and garden monitoring systems. Check out the tutorial under Datasheets on how to get started with your DHT11 sensor

This sensor is a basic digital temperature and humidity sensor. It uses a capacitive humidity sensor and thermistor to measure the air and transfers a digital signal to the data pin.

This sensor comes mounted to small PCB which includes a surface mounted 10K Ohm pull up resistor for the signal line. It also eliminates the 4^th pin that is not used. The pinout is as follows:

How it works:

To detect humidity, the DHT11 measures the electrical resistance between two electrodes. The electrodes are on the surface of the component which is a moisture holding substrate. As the substrate absorbs water, ions that increase the conductivity between the two electrodes are released. This change in resistance is proportional to the relative humidity. The resistance between electrodes will decrease with higher relative humidity and increase with lower relative humidity.

To measure air temperature, the device uses a surface mounted (SMT) NTC temperature sensor, or a thermistor. Thermistors are variable resistors that change resistance based on the temperature. This thermistor’s resistance will decrease when the temperature increases.

Specifications:

• 3 to 5V power and I/O
• 2.5mA max current use during conversion (while requesting data)
• Good for 20-80% humidity readings with 5% accuracy
• Good for 0-50°C temperature readings ±2°C accuracy
• Dimensions: 15.5mm x 12mm x 5.5mm
• 3 pins

Arduino Connection