The glass substrate, the lower electrode, the humidity-sensitive material, as well as the upper electrode make up the majority of humidity sensor. These two lower electrodes, the humidity sensitive material, as well as both capacitors created by the upper electrodes are all connected in the series form. A large molecular polymer called a humidity-sensitive substance alters its dielectric constant depending on the environment’s relative humidity.
When the relative humidity varies, its humidity sensor capacitance also changes, and vise – versa, the humidity sensor’s capacitance adjusts to the change in environmental humidity (the capacitance usually falls within 48 to 56 pf). This humidity-sensitive capacitance adjustment is converted by the conversion circuit of the sensor into a change in voltage that reflects a relative humidity change from 0% to 100 percent RH, as well as the sensor’s output changes in a linear way from 0v to 1v.
Typical Arduino Humidity Sensors
The most popular humidity sensors that are appropriate for Arduino projects are included in this section.
The most often used humidity sensor is from the DHT series. All of them feature automated calibration, are really simple to use, as well as contain the Arduino software libraries, which is well-liked by makers. Let’s examine DHT11’s capabilities.
Old DHT11
- For the DC operating voltage, it has a value of 3.3 to 5.5 volts
- In addition, its range of temperature falls between 0 to 50 °C
- The Range of Humidity falls between 20 to 95% RH
- Its Temperature Accuracy falls within ±2℃A
- Also, its Humidity Accuracy falls within ±5%RH
- Type of Sensor: Sensor for resistive humidity
The DHT11 has a limited measurement range as well as low measurement precision frequently applied in several student projects. There’s an upgraded version of the DHT11, which is wonderful news.
The resistive humidity sensors were replaced by the capacitive humidity sensors by the manufacturer, and the upgraded DHT11 has considerably better measurement range.
Recent DHT11
Here, electrical resistance across two electrodes is measured by the DHT11 in order to identify water vapor. A moisture-holding substrate having electrodes placed onto the surface serves as the humidity sensor component. Ions are generated by a substrate whenever water vapor gets absorbed by it, increasing the conductivity in between these electrodes.
- For the DC operating voltage, it has a value of 3.3 to 5.5 volts
- In addition, its range of temperature falls between -20 to 60 °C
- The Range of Humidity falls between 5 to 95% RH
- Its Temperature Accuracy falls within ±2℃
- Also, its Humidity Accuracy falls within ±5%RH
- Type of Sensor: Sensor for capacitive humidity
DHT22
The top-tier DHT22 model, also referred to as RHT03 or AM2302, is part of DHT series. Both its measuring range as well as high accuracy in measurement is very broad.
- For the DC operating voltage, it has a value of 3.3 to 5.5 volts
- In addition, its range of temperature falls between -40 to 80 °C
- The Range of Humidity falls between 0 to 99.9% RH
- Its Temperature Accuracy falls within ±0.5℃
- Also, its Humidity Accuracy falls within ±2%RH
- Type of Sensor: Sensor for capacitive humidity
DHT22 can be employed in the meteorological, medical, as well as different professional fields. It also has superb long-term stability.
AM2311A
A humidity and temperature compound sensor with a calibrated signal output is the AM2311A humidity and temperature module. In order to ensure the product does have very high dependability and great long-term stability, it uses sophisticated digital acquisition technology as well as humidity and temperature monitoring technology.
- For the DC operating voltage, it has a value of 3.3 to 5.5 volts
- In addition, its range of temperature falls between -40 to 80 °C
- The Range of Humidity falls between 0 to 99.9% RH
- Its Temperature Accuracy falls within ±0.5℃
- Also, its Humidity Accuracy falls within ±3%RH
- Type of Sensor: Sensor for capacitive humidity
How to Select the Most Effective Arduino Sensor Humidity
Large performance and price discrepancies exist between various humidity and temperature sensors. How then should you select the best sensor to suit your projects?
Measure Range
The range of measurement must be established prior to choosing any humidity sensor, just like with temperature and weight measurements. Humidity and temperature control and measurement typically do not call for full humidity (which is 0 to 100% RH) in measurement, with the exception of scientific and meteorological research departments. Choose a range which best suits the needs of your project because, broadly speaking, the greater the range, the more expensive it will be.
Accurate Humidity
The humidity sensor’s most crucial indicator is measurement accuracy. This humidity sensor advances one level or a grade per each increase in percentage point. Its manufacturing costs as well as selling prices differ wildly because varied precisions must be attained. The DHT11 protocol is enough for most tasks. The 5–95% RH measuring range would satisfy majority of applications out there.
What are the Uses of the Arduino Sensor Humidity?
Monitoring the climate
For the purposes of scientific research, military operations, and agricultural and industrial production, weather observation as well as forecasting are extremely important. Thus, humidity sensors serve as a crucial piece of equipment for humidity measurement. For instance, the meteorological balloon measuring equipment for humidity has utilized resin swelling sensors for humidity.
Greenhouse Breeding
There are many greenhouses in the modern forestry, agriculture, as well as animal husbandry businesses. The greenhouse has to control its humidity just as much as its temperature. One requirement for lowering pests and illnesses and raising output is controlling humidity inside a range that is favorable for the development of crops, livestock, trees, and poultry.
Industrial production
Air humidity has a direct impact on product output and quality in the electronics, textile, precision machinery, ceramics, and other industries, so it needs to be adequately controlled and managed.
Conclusion
It’s quite simple to include temperature and humidity data to the DIY electronic applications when utilizing an Arduino sensor humidity. It is ideal for outdoor weather stations, indoor climate management systems, including garden or farm monitoring systems.
