You have five sense organs in your body that take in information from your environment and send it to your brain. Your brain then processes the information and tells your body how to respond. The sense organs are your eyes, ears, nose, tongue and skin.
In IOT Architecture two things are very important: The Internet and the physical devices like sensors and actuators. … The main purpose of sensors is to collect data from the surrounding environment similar to your sense organs. Sensors, are calling ‘things’ of the IoT system.
These following features should be at the base of a good sensor:
- It should be very sensitive to the environment that it measures
- It should not be sensitive to other physical change which it does not support.
Characteristic of Sensor.
- Reliability
- Accuracy
- Size
- Weight
- Volume
- Range etc.
sensors and actuators
- Sensor: an input transducer (i.e., a microphone)
- Actuator: an output transducer (i.e., a loudspeaker)
Sensor Classification
Sensors can be classified in simple way using several criteria:
- Passive or Active. Passive sensors do not require an external power source to monitor an environment, while Active sensors require such a source in order to work.
- Another classification is based on the method used to detect and measure the property (mechanical, chemical, etc.).
- Analog and Digital. Analog sensors produce an analog, or continuous, signal while digital sensors produce a discrete signal.
Some common types of IoT sensors
Temperature sensors
These devices measure the amount of heat energy generated from an object or surrounding area. We generally use it in refrigerator, air-conditioner etc. You can also use it in agriculture and health etc.
Humidity sensors
The amount of water vapor in air, or humidity can be measured by this sensors.
Motion sensors
Motion sensors are not only used for security purposes but also in automatic door controls, automatic parking systems etc.
Gas sensors
These sensors are used to detect toxic gases.
Smoke sensors
Smoke sensors have been in use in homes and industries for quite a long time. These are used in Smoke detector.
Pressure sensors
These sensors are used in IoT systems to monitor systems and devices that are driven by pressure signals. When the pressure range is beyond the threshold level, the device alerts the user about the problems that should be fixed. For example we can use tyre pressure sensor in our car.
Accelerometer sensors
These sensors are used in smartphones, vehicles, aircrafts and other applications to detect orientation of an object, shake, tap, tilt, motion, positioning, shock or vibration.
Proximity sensors
These sensors detect the presence or absence of a nearby object without any physical contact.
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