Embedded systems is one of the most important, yet overlooked subjects in the electronics world. When you think technology, mobile phones, tablets and laptops come to mind, but the devices that actually help us in our daily lives are not talked too much about. They’re often confused with larger or more general purpose computers, and it’s sometimes difficult to discern between one and the other. However, once you understand what embedded systems are used for, and for that matter defined as, it’s pretty easy to see what is used where. Here’s all you need to know about embedded systems, its history, types, characteristics and more!
An embedded system is a computer system, made from a combination of hardware and software, that is used to perform a specific task. It may or not be programmable, depending on the application. Examples of embedded systems include washing machines, printers, automobiles, cameras, industrial machines and more. In case you’re wondering, yes, mobile phones and tablet are also considered embedded systems. Embedded systems are named as such because they’re part of a larger device, providing a special function. They use both microcontrollers and microprocessors, as well as specially designed processors such as digital signal processors (DSP).
There’s a lot of confusion between the actual definition though, since mobile phones and tablets can be called embedded systems, yet are also termed as full fledged computer systems. On the other hand, traffic signals, washing machines and digital watches can be considered embedded systems, but definitely not complete computer systems. Depending on the complexity, systems may transcend definitions, but the clearest idea about embedded systems is gotten from electronic devices and appliances used everyday, which perform specific functions and aren’t just simple mechanical devices.
Embedded systems trace their history back to the 1960’s. The Apollo Guidance System, built by Charles Draper at MIT, is considered one of the first modern embedded systems. Used in the Apollo Command Module and Lunar Module, it was used for navigation, guidance and control of the respective crafts. Using a numeric display and keypad, the Apollo Guidance System was somewhat of a risk, since it was the first of its kind. Over the years, however, it was repeatedly used and refined in a lot of NASA’s space missions. Then came the Autonetics D-17 Guidance Computer for the Minuteman Missile, an ICBM (Intercontinental Ballistic Missile) used by the United States Air Force.
Ostensibly, these highly specific systems were part of non-commerical projects and were thus extremely expensive. It wasn’t until the late 70’s that Intel’s 4004 microprocessor broke the path for cheaper and more accessible embedded systems. Once microcontrollers were introduced in the 80’s, it took over the market since it was significantly cheaper than general purpose computers. Thus, modern accessible embedded systems were born, and as time progressed, they got more complex and smarter, making life much easier. Cut to today, and you have washing machines that adjust themselves according to loads, refrigerators that dynamically change cooling (and let you tweet!) and much more. Today, almost everything depends on embedded systems.
So we’ve seen the history of embedded systems and know a little bit about where they’re used, but there’s always been a little confusion among most regarding their characteristics. What makes an embedded system? What are its characteristics? What do we see in a typical embedded system? Here’s some of their characteristics:
- Embedded systems are task specific. This is part of the definition, in fact. They may be part of a refrigerator that lets you tweet, but no matter how smart it may seem, it’s still a refrigerator. Similarly, you will find embedded systems for networking tasks, computing, sensing, so on and so forth.
- A lot of embedded systems are created with time constraints in mind. In some situations, crossing time limits might not amount to much, but in some, it may actually be a disaster. For example, if the embedded system in a car’s braking system doesn’t strictly adhere to time, it may result in an accident. However, if a time limit is passed on something less severe, it may just result in reduced performance.
- Although modern complex embedded systems may come with a user interface, in general, they possess either no UI or just a minimal UI.
- Embedded systems are usually feedback oriented or reactive. They function either by interacting with external stimuli, or depend on another system to give them an input.
- They are built with efficiency and frugality in mind. Since embedded systems, by definition, are part of larger computer systems, they should be able to work without drawing too much power and shouldn’t be too expensive.
- Embedded systems should be highly reliable and stable. Unlike usual computers, embedded systems use different underlying software that cannot be modified by consumers. Since they will be used for long periods of time and cannot be programmed easily, they’re expected to run without any problems. In the case of some applications like undersea communication cables, navigation beacons or automobile components, maintenance is extremely difficult, if not highly improbable, so reliability is paramount.
Embedded systems are used in a variety of applications. They’re so versatile that they can pretty much be used for any application, so it might seem almost impossible to categorize them. However, based on performance and functional parameters, embedded systems can be broadly classified into the following four categories:
- Standalone Embedded Systems – As the name suggests, these are embedded systems that can work by themselves. In other words, they are self sufficient, and don’t require a host system or computer to function. While they will require inputs and other devices for output, the processing and work is done only by themselves. Examples include videogame consoles, music players and microwave ovens.
- Real-time Embedded Systems – An embedded system that gives an output within a specified amount of time is called a real-time embedded system. That is, in addition to a proper output, it adheres to time constraints as well. They can be further classified into soft real-time embedded systems and hard real-time embedded systems.
- Networked Embedded Systems – Embedded systems that are connected to a network and depend on it for their functioning are called networked embedded systems. They may or may not have smaller or less complex subsystems running to create the network. Examples include home security systems and heat sensor systems.
- Mobile Embedded Systems – Embedded systems meant for mobile communications are called mobile embedded systems. They include mobile phones, tablet computers and the like, and are usually categorized by functions like internet, calling, in addition to more complex functions seen in today’s smartphones.
Where are they used?
So we’ve mentioned that embedded systems are widely used all around the world. But how widely do we actually mean? From end user electronics to industrial applications, embedded systems are actually everywhere. Here’s some applications:
- Consumer electronics – Mobile phones, videogame consoles, printers, Blu-Ray players, home entertainment systems, televisions, digital cameras, music players
- Household appliances – Washing machines, microwave ovens, refrigerators, dishwashers, air conditioners
- Medical equipment – CT Scanners, Electrocardiogram (ECG), MRI Scanners, blood pressure monitors, heartbeat monitors
- Automobiles – Electronic fuel injection systems, anti lock braking systems, in-vehicle entertainment systems, air-conditioner controls
- Industrial applications – Assembly lines, multiple parameter monitoring systems, feedback systems, data collection systems
- Aerospace – Navigation systems, guidance systems, GPS
- Communications – Routers, network hubs, satellite phones
The list goes on and on, so it’s pretty safe to say that embedded systems have changed mankind for the better.
Just think about it, almost every advance made by humankind, every device or appliance that helps us in our daily lives and even what creates those devices are embedded systems. Without embedded systems, where would we be? Would it be possible for us to create wonders like driverless cars, fully automated factories, adaptive home appliances and more? Probably not. So if you’re thinking about studying about a subject that quite literally is changing the future, look no further than embedded systems!