Sensing Temperature
Types of Sensors
There are several types of temperature sensors that are commonly used in home automation, including:
Thermistors: These are commonly used in thermostats for controlling heating and cooling systems in homes. They can also be used to monitor the temperature of specific areas in a home.
Digital temperature sensors: These are small, low-cost sensors that are easy to install and can be connected to a home automation system. They are commonly used to monitor temperature and humidity in a home.
Infrared sensors: These are often used to measure the temperature of objects or people in a room, and can be used for home security or monitoring the temperature of cooking appliances.
WiFi-enabled temperature sensors: These are sensors that connect to a home WiFi network, allowing them to be remotely monitored and controlled using a smartphone app or other web-based interface.
The specific type of temperature sensor used in home automation will depend on the specific application and requirements of the system.
ESPHome is a popular platform for building DIY smart home devices, and it supports several types of temperature sensors. Some of the most commonly used temperature sensors in ESPHome include:
DHT sensors: These are low-cost sensors that can measure both temperature and humidity. They are commonly used in DIY smart home projects and can be easily integrated with ESPHome.
DS18B20 sensors: These are digital temperature sensors that communicate using the OneWire protocol. They are accurate and easy to use, and are often used in temperature monitoring applications.
BME280 sensors: These sensors can measure temperature, humidity, and pressure, making them useful for monitoring indoor environments. They communicate using the I2C protocol and are commonly used in ESPHome projects.
AM2302 sensors: These are similar to DHT sensors but have a slightly higher accuracy. They are also commonly used in DIY smart home projects and can be easily integrated with ESPHome.
ESPHome also supports other temperature sensors such as BMP280, HTU21D, and SHT3X. The specific type of sensor used will depend on the application and the specific requirements of the project.
DHT11 vs DHT22
What is DHT11?
DHT11 can be referred to as a basic, low-cost humidity and temperature sensor. It has the capability to detect relative humidity and temperature. The relative humidity here refers to the quantity of air’s water vapor compared to the water vapor’s saturation point in air.
Furthermore, DHT11 is widely regarded as the humidity and temperature module for Raspberry Pi and Arduino. Therefore, due to its many benefits, hardware enthusiasts favor the DHT11. Also the DHT11 humidity temperature sensor also works with respect to the new DHT11 module.
Features
Consumes low power and has a great long-term stability
You can obtain a relatively high accuracy in measurements at a low and affordable cost
Range of humidity falls between 5 – 95% RH, and having a ±5%. Also, the range of temperature falls within -20 – 60℃ and having a ±2%.
Comparing the old and new DHT11, we can see some differences. The old DHT11 is called ADSONG, while the new is ASAIR.
The old DHT11 has a resistive sensor, while the new DHT11 has a capacitive sensor
Old DHT11 has a humidity range falling between 20 and 95%, while the new DHT11 has a humidity range that falls between 5 and 95%
The old DHT11 has a temperature range falling between 0 and 50℃, while the new DHT11 has a temperature range that falls between 20 and 60℃.
The old DHT11 has a temperature resolution of 1℃, while the new DHT11 has a temperature resolution of 0.1℃.
From this comparison, you can clearly see that the new DHT11 has a wider range for both humidity and temperature. Furthermore, its temperature resolution is also lower.
What is DHT22?
DHT22 is also referred to as RHT03 or AM2302. The DHT22 features a temperature sensor with high precision, as well as a humidity sensor. It makes use of a digital module acquisition technology, as well as humidity and temperature sensing technology. This is just to ensure that it is highly reliable and has great long-term stability.
Furthermore, DHT22 features a sensing element, as well as a measuring element of temperature of high precision, which is connected to an 8-bit microcontroller of high performance. Therefore, it has great quality benefits, very quick response, high-cost performance, and high anti-interference ability.
Features of the DHT22
Its size is ultra small
Power consumption is extremely low, coupled with a distance of signal transmission of over 20 meters. Therefore, it can withstand applications that are most demanding.
Range of the humidity sensor falls between 0 – 99.9% RH, and has an accuracy of ±2%. Also, the range of temperature falls within -40 – 80℃ and has an accuracy of ±0.5℃.
Note that the sensor module can be sold individually. Also, connection with 3 leads is easy. If you wish to connect the sensor using a longer wire, all you need to do is include a pull-up resistor.
What are the Differences: DHT11 vs DHT22
Temperature range: With respect to the temperature range, for DHT11, it falls within -20 – 60℃, while for DHT22, it falls within -40 – 80℃.
Temperature accuracy: DHT11 has a temperature accuracy of ±2%, while that of DHT22 is ±0.5℃
Humidity Range: the humidity range for DHT11 falls between 5 – 95% RH, while that of DHT22 falls within 0 – 100%RH.
Humidity Accuracy: DHT11 has a humidity accuracy of ±5%, in contrast to DHT22, which is ±2%.
Cost: The cost of DHT11 is $5.90 compared to that of DHT22, which is $9.90.
In conclusion, in all aspects, the DHT22 beats the DHT11. This includes humidity accuracy, humidity range temperature accuracy, and temperature range. DHT22 has just one downside, which is its higher price compared to that of DHT11. However, this is necessary, since you have to pay more to get the better deal.
Therefore, if you are searching for a sensor having a wider accuracy and range, then you should choose the DHT22. However, if you decide to choose the DHT11, no problem; it will also work well for your different projects.
Generally, both DHT sensors are regarded as slow and basic humidity and temperature sensors, which are great for hobbyists and beginners seeking to do some data logging. Both utilize one digital pin and function very slowly. You cannot query both sensors more than once for each second.
DHT22 Specifications:
Type: temperature and humidity sensor (DHT22).
Operating voltage: DC 5.5 V.
Temperature range from -40 ° C to 80 ° C.
Temperature measurement accuracy: ± 0.5 degrees Celsius.
Measuring range for air humidity: 0-100% RH.
Humidity measurement accuracy: ± 2% RH.
Operating voltage: DC 5 V.
Size: 28 x 12 x 10 mm (L x W x H).
Screw hole diameter: 2.6 mm.
Weight: 4 g.
With hole for fastening screw, easy to install and fix.
Single bus digital signal output, serial ports data Bidirectional interface.