What is a sensor
Internet of Things (IOT) is the forebearer of the 4th industrial revolution. And the whole concept of IOT is reliant on sensors.
A sensor is a device that senses or measures some physical value and converts that measurement into a form that can be represented digitally. This digital representation is sent to other devices that transforms it into useful data. This useful data or information can then be consumed by intelligent devices or humans.
Sensor vs Human Senses
The functionality of a sensor can be paralleled with humans and the use of their five senses to learn about their surroundings. Human senses cannot operate and function independently, all five senses complement each other and compute together, allowing the human brain to make intelligent decisions. Several sources of sensory input is used to validate an event and compensate for “incomplete” information by the human brain, which makes the final decision.
Sensors are not limited to data that can be perceived by humans. They can measure anything tangible that is measurable. In fact, they are able sense measurement data that is unmeasurable with human senses and with far greater precision. Modern sensors can be easily integrated into any objects, that are then connected to the internet by wired or wireless networks. These sensors then communicate with each other and the external systems, allowing them to interpret their environment and make intelligent decisions.
Categories of sensor
There are numerous sensors capable of measuring a vast array of data. There are a number of ways to group these sensors into different categories. Some of the categories include:
- Active sensor or passive sensor: Sensors can be categorized based on whether they require an external power supply (active) or whether they require no external power supply (passive).
- In-contact sensor or no-contact sensor: If the sensor is touching or in contact with what it is measuring, they are called contact sensor. If the sensor is not in contact with what it is measuring, they are called no-contact sensor.
- Absolute sensor or relative sensor: If the sensor measures on an absolute scale it is called absolute sensor. If it measures on a relative value it is called relative sensor.
- Invasive sensor or non-invasive sensor: When a sensor is part of the environment it is measuring it is called non-invasive sensor. If the sensor is not part of the environment it is measuring it is called invasive sensor
- What sensors measure: Sensors are categorized based on what physical variables they measure, or their applications.
- Area of application: Sensors are categorized based on the specific field or industry where they are used.
- How sensors measure: Sensors are grouped into categories based on the physical mechanism used to measure sensory input. For example, optic, electric, chemical, pressure, vapor etc.