Single board microcontrollers are in many electronics applications, developing customised systems for individual subsystems and combining them to meet requirements is more productive than having one all-encompassing solution. Single board microcontrollers are affordable components for software-based solutions to individual control and/or data preparation tasks. They deliver the required intelligence exactly where it is needed in mechatronic units where space is limited.
For many people, terms like “digitalisation” or “Internet of Things” conjure up images of personal usage — smartphones, for example, tablet PCs or digital assistants like Alexa. These days, saying “computer-controlled” still makes most people think of things like programmable logic controllers (PLC) or PCs, or possibly of large control cabinets packed with computer hardware.
Modular control with single board microcontrollers
However, ongoing miniaturisation in microelectronics has significantly changed and expanded the options for creating and developing electronic and computer-controlled systems. The more affordable and accessible that processing power and memory capacity become, the greater the number of functions that can be implemented within individual projects. As this is causing a disproportionate growth in the development effort and expense for complex projects, custom solutions are increasingly being created for specific subtasks and combined to create an overall solution that meets the relevant requirements.
That is why microprocessors and controllers have long been used in low-profile devices and technical systems such as car radios, ABS systems and even the good old room thermostat. It is entirely possible that something like a gas meter has greater computer intelligence than a PC in the accounts department. And the trend has long since been moving in the same direction in industrial applications. Devices that were once completely mechanical are now being upgraded to independent devices with processor and/or controller boards. Where they were previously controlled down to the last detail by superordinate systems, the modular design of the overall task means that they can now focus on their coordinating role.
Put into practice
To give an example that illustrates that this development is nothing new, skiers and visitors to trade fairs and stadiums are familiar with access control systems that check the validity of admission tickets. These are complex systems where a range of types of electronic data processing interact with each other. Traditional computer systems run in the background to configure and control the system as a whole, to collate and prepare the data collected by the card readers and to carry out further checks.
The card readers themselves have dedicated processor hardware and software that enable them to check the validity of tickets and store the relevant data. In addition, most other processes or controllers handle the movement of cards in the reading mechanism, preprocessing magnet or chip data and communicating with the surrounding system. And it doesn’t stop there: programmable systems that are integrated into the turnstile control the movement of the rails in line with the operational situation.
Flexibility through local intelligence – with single board microcontrollers
In the past, hard-wired electronics operated hand in hand with mechanical hardware. These days, however, processors or controllers are more likely to be integrated into devices to provide the required intelligence. This gives these devices a level of flexibility and independence from surrounding systems that they would otherwise not have and also means that they can easily be integrated into larger overall solutions, either directly or via the Internet of Things (IoT).
Solutions with integrated processors are commonly referred to as embedded systems. The term may be common, but there is a certain lack of clarity about what exactly it means. This overview of the situation is designed to shed more light on the topic.
Fluid boundaries
The boundaries between embedded systems and traditional computers are naturally fluid, given that complete PCs can now be fully integrated into other systems. An essential distinguishing factor, however, is that they usually only handle communication functions and control tasks for the devices in which they are embedded.
The boundaries are even less clear when it comes to the term mechatronics. There is something of an overlap here, as the intelligence for devices where electronics is embedded in mechanical systems is increasingly being provided by processes and/or microcontrollers instead of hard-wired logic. On the other hand, embedded systems extend far beyond the original scope of mechatronics, as they are frequently integrated or embedded in the complex, mechanical inner workings of the device, rather than in separate control cabinets or enclosures. Hence the name.
Separating hardware and software
As recently as 15 years ago, the hardware and software for embedded systems had to be developed individually. That required thorough technical knowledge, not just for programming microcomputer systems, but also for creating professional designs for complex electronic circuits. Even then, software in traditional computer systems was developed separately from the largely standardised hardware, allowing software developers to focus on their key task.
Single board computers the size and shape of a credit card—like the Raspberry Pi that was launched in 2012—are essentially complete PCs and bring this advantage within the reach of home users and education providers. More importantly, they can also be used for embedded systems. The advantages delivered by this modular design and standardised approach have allowed these products to make inroads in areas where industrial electricians wouldn’t immediately expect to find them — including fuel dispensers, drinks dispensers and coffee machines.
Modular design and standardised approach
Sven Pannewitz, Product Manager for Single Board PCs and Developer Boards at electronics distributor reichelt elektronik, explains current developments: “The clear trend is towards a modular design and standardised approach, for both hardware and operating system platforms. In addition, as well as PC-like systems, there is also a wide range of single board control systems with numerous inputs and outputs to support direct interaction with sensors and actuators.”
When it comes to single board computers like the Raspberry Pi, the days of one single product are long gone. On that basis, the PiXtend brand, for example, now has a line of PLC boards for sophisticated control tasks At the other end of the spectrum, there are smaller single board microcontrollers like the boards from the open-source Arduino platform, as well as the Nucleo development boards with ARM Cortex™ controllers. The latter are compatible with the Arduino boards when it comes to connectivity.
Small specialists – Single board microcontrollers
Single board microcontrollers like that are compact special platforms for individual control or data preparation tasks. Their small dimensions mean that they can be used where space is tight, so that they can solve these issues exactly where they are needed. Digital analogue inputs and outputs allow the single board microcontrollers to communicate directly with connected peripherals. Connecting to the outside world is easy, thanks to adapters for a range of technologies, including WIFI and GSM.
Unlike single board computers with PC architecture, these small specialists do not need an operating system as they are responsible for running programs that have been developed for a specific purpose, compiled via a free development environment and transferred to the module. In many cases, users can assemble these programs from functions that are available free of charge online. This means that even users without specialist software knowledge can quickly achieve very impressive results.
Diversity requires variety
Despite that, a very good understanding of the task is essential for creating meaningful practical applications. That includes being familiar with the mechanical components to be controlled and how to equip them with sensors and actuators, as well as a clear design of displays for guiding users and exchanging data with neighbouring or superordinate systems.
These criteria also apply to selecting suitable boards. The number of analogue and digital inputs and outputs is determined by both the intended application and the space available. The addition of communication interfaces and network connections—to a CAN bus, for example—is based on the system environment in which the product is to be used.
Other criteria often involve weighing different factors against each other. For example, the processing capacity of the microcontroller chips and the addition of memory in the form of RAM, Flash ROM and EEPROM will affect the module’s energy consumption. As Pannewitz advises: “You should therefore define your specific performance requirements and not overestimate to allow for increased demand in the future, especially for applications in battery-operated systems. Generally speaking, the manufacturers of these boards launch successor products that are compatible in terms of shape, connection and program on an ongoing basis.”
Here to stay
Embedded systems are neither new nor revolutionary. The ongoing miniaturisation of electronics components is facilitating a further distribution of intelligence in complex systems and enabling software parts to move closer to where they are needed — i.e. close to hardware and mechanical components. This allows technical systems to become even more responsive to people and their changing needs.
As Pannewitz says: “Single board microcontrollers are an effective way of doing that. They are extremely versatile and amazingly easy to use. When it comes to choosing the right one for you, it makes sense to work with a partner with a broad range, so that you have the best chance of choosing the exact size for the task in question.”
Image: Adobe Stock
