What does IoT (Internet of Things) use to capture data from the real world?

Concept

An IoT (Internet of Things) system interfaces with the physical world through two complementary classes of hardware: input devices that capture real-world data (temperature, motion, light, pressure, humidity, and so on) and output devices that act on the environment based on decisions made from that data. The input-side devices are called sensors; the output-side devices are called actuators. A sensor converts a physical phenomenon into an electrical signal (data); an actuator does the reverse - it converts an electrical/processed signal into physical motion or action.

Application

1. The question asks specifically about capturing data from the real world - the sensing/input side of an IoT system.

2. That is precisely the role of a sensor: a temperature sensor captures ambient temperature, a motion sensor captures movement, a light sensor captures illuminance, and so on - each converts a real-world physical quantity into data.

3. This captured data is then processed by a computing unit (often a microcontroller or microprocessor) and may go on to drive an actuator - but the data-capture step itself is performed by the sensor.

Cross-check

• Actuators perform the opposite role - they act on the environment (driving a motor, opening a valve, triggering a relay) using already-processed data; they do not capture data from the environment.

• A microprocessor is a general-purpose processing unit that executes instructions on data already supplied to it; it has no direct interface to physical-world phenomena, so it cannot itself capture real-world data.

• A microcontroller integrates a processor with memory and I/O on a single chip and can read a sensor's output or drive an actuator, but the real-world data-capture step is performed by the attached sensor, not by the microcontroller itself.