Sensors and Actuators

Sensors in Embedded Systems

Sensors are devices that measure physical quantities and convert these into signals which can be read by an observer or by an instrument.
In the context of embedded systems, sensors collect data from the physical environment. This data can be used to control the system and to make decisions based on the environment’s current state.
Different types of sensors include temperature sensors, light sensors, pressure sensors, motion detectors, and humidity sensors among others.
Analogue sensors produce a continuous output signal that is proportional to the quantity being measured, while digital sensors produce a binary output.

Actuators in Embedded Systems

An actuator is a device that moves or controls a mechanism or system. In embedded systems, actuators are typically used to cause some form of physical change in response to inputs.
Actuators convert an input signal into a physical action. For example, when a motor receives an electrical signal, it rotates.
Selection of actuators will depend on the type of physical action needed. This could include motors for rotational movement, solenoids for linear movement, or relays to turn electrical circuits on and off.

Using Sensors and Actuators in Embedded Systems

In an embedded system, sensors are connected to Input pins, while actuators are connected to Output pins of the microcontroller.
Signal Conditioning is required when an analogue sensor is used, as the microcontroller can only handle digital signals. This process involves converting the sensor’s output into a digital form.
The output from the sensor is analysed and based on the result, the program running on the microcontroller will control the actuator.
Key to a successful embedded system design involving sensors and actuators is understanding the physical properties you want to monitor or control, and selecting the appropriate sensor/actuator combination to accomplish that goal.