Intelligent sensor

The sensor has to do the following tasks:

• Give a digital signal.
• Be able to communicate the signal.
• Be able to execute logical functions and instructions.

An intelligent sensor integrates both analogue and digital subsystems, combining sensing, signal conditioning, conversion, compensation, and communication functions in one unit. Each element contributes to transforming a physical quantity into reliable digital information suitable for higher-level processing.

The main components are:

• Primary sensing element, the core transducer that converts a physical quantity (such as temperature, pressure or acceleration) into an electrical signal.
• Excitation control, provides the necessary stimulus or bias to the sensing element and can vary depending on the sensing principle and application.
• Amplification, increases the weak signal from the sensing element.
• Analogue filtering, removes unwanted noise and prevents aliasing before the signal is converted to digital form.
• Data conversion, converts the conditioned analogue signal into digital form.
• Compensation, corrects variations in sensor behaviour.
• Digital information processing, compresses, validates and interprets data, checking the integrity and consistency of measurements before transmission.
• Digital communication processing, handles addressing, protocol management and error checking during data exchange with external systems.

Because the tasks are performed by microprocessors, any gadget which mixes a sensor and a microprocessor is usually called an intelligent sensor.

To qualify as an intelligent sensor, the sensor and processor must be part of the same physical unit. A sensor whose only function is to detect and send an unprocessed signal to an external system which performs some action is not considered intelligent.

Ubiquitous Sensor Networks (USN) is used to describe a network of intelligent sensors that could, one day, become ubiquitous.