DHT11 Sensor and Its Working

• DHT11 is a Humidity and Temperature Sensor, which generates calibrated digital output. It ensures high reliability by employing an exclusive digital-signal-acquisition technique as well as temperature and humidity sensing technology.
• It measures the surrounding air with a capacitive humidity sensor and a thermistor and outputs a digital signal on the data pin (no analog input pins needed).
• Each DHT11 element is rigorously calibrated in a laboratory to ensure extreme accuracy in humidity calibration.
• The calibration coefficients are stored in the OTP memory as programs that are used by the sensor’s internal signal detecting process.
• The single-wire serial interface speeds up and simplifies system integration. Its small size, low power consumption, and signal transmission range of up to 20 meters make it the best choice for a wide range of applications, including the most demanding.

• Sandwiched between two electrodes is a moisture-holding substrate (typically a salt or conductive plastic polymer). The ions are released by the substrate as it absorbs water vapor, increasing the conductivity between the electrodes.
• The resistance difference between the two electrodes varies proportionally to the relative humidity. Higher relative humidity reduces the resistance between electrodes, whereas lower relative humidity increases the resistance between electrodes.
• They also include an NTC temperature sensor/thermistor for temperature measurement. A thermistor is a thermal resistor, which means that its resistance changes with temperature. Technically, all resistors are thermistors but the difference is usually very small and difficult to detect.

Applications of DHT11 Sensor

• DHT11 sensor can be used in various applications such as weather stations in the area, automatic climate control, environmental surveillance, etc.
• It can be used in medical equipment such as sterilizers, incubators, ventilators, and so on where humidity control is required.
• In biological and pharmaceutical processes, humidity sensors are also required there also DHT11 can be brought into use.
• Humidity sensors in HVAC (Heating, Ventilation, and Air Conditioning) systems are critical for maintaining proper climate conditions while conserving energy.