What is an embedded system?

The term ‘embedded’, when used in an industrial context, may be best categorised as a computing term. This is important as it is an oversimplification to consider an embedded system solely a ‘system within a system’ (or, to be slightly more precise, a ‘system within another, larger and more sophisticated system’.

After all, the nature of such systems need to be specified to truly define embedded systems, because otherwise one could argue that an infotainment interface is a system embedded within a car.

This argument is of course false: it merely reflects the fact that larger technologies can power and accommodate smaller technologies (for example, think of a computer that contains the input of a USB stick). In fact, by applying such a misuse of the term, one could even make the false claim that a manual handbrake is a braking system embedded within a car.

Again, this is incorrect: it not only takes the word ‘embedded’ out of the industrial context, but it also suggests that embedded systems can be mechanical. As will be reflected next, they can only ever be relevant to electronic processes.

Nevertheless, the above mentions of vehicular systems do bring up an important point: that the automotive industry contains many strong examples of embedded systems at work – and drivers take them for granted every day. Consider what are some of the main processing technologies of a vehicle: the electronic control units (ECUs).

An ECU is a textbook example of an embedded system: it can be defined as an automotive integrated circuit, specifically a microcontroller (MCU), which receives a response from the car’s sensors and responds by utilising the vehicle’s actuators to achieve the necessary response.

An example of such a function can be seen in the car’s airbag crash response technology: the sensors inform the dedicated ECU that a crash has occurred, and the embedded system achieves its purpose once that ECU has commanded the car’s actuators to release the airbag. It is a calculated response, owing to the dedicated chip in the electronic control unit.

This is important as, again, embedded systems must by definition embody the use of software (which is one reason why the term ‘embedded systems’ goes hand in hand with another industry term: ‘embedded computing’).

Within any modern vehicle, the ECUs are one of many (80 or more) MCUs that utilise hundreds, even thousands, of data points produced by the sensors of a vehicle. These are all integral to the functionality of the car’s subsystems, such as the automatic control of the car’s ideal AC settings based on the sensors’ temperature readings. 

Luxury cars now almost universally have the ‘AUTO’ function for their air conditioning: it is known as automatic climate control and is one of the many, prominent examples of a car’s subsystems that is made possible by the communication between sensors and embedded ECUs, which respectively gauge the car’s cabin temperature and control the air conditioning accordingly.

But the use of embedded microcontrollers to achieve optimal temperatures is far from only applicable to the automotive industry of course: consider the importance of similar thermal embedded management systems in laptops, smart homes, and plenty more.

The question arises: where are we seeing – and will continue to see – embedded systems thrive? The answer may well be the Internet of Things. This is why the aforementioned words ‘sensors’ and ‘subsystems’ are especially important: embedded systems are the tools by which the IoT can process the data that is gathered by sensors and processed through countless subsystems.

After all, nowadays, a connected car does not just gather data for the benefit of its users: the information is integral to such IoT operations as vehicle to everything. And no such operations would exist without the embedded systems required to process them.