The current developments in the society would not be possible without the information processing technologies. And now, all the senior residents understand the importance of mobile network: now they can easily communicate with the neighbours and children living in the city. Hardly anybody even dreamed about such possibility. One or another dominant kind of progress affects the direction of further development of the society.
For simple specialized tasks mostly used are embedded systems (ES). ES are electronic systems embedded into a complex unit and performing device control functions according to the allocated application. These systems are called embedded because they can be mounted or inserted into the same device they control due to their small dimensions. Consumers do not even notice that such ES carries out the hard work in their devices.
Architecture and structural parts of embedded systems
ES are systems intended for carrying out specialized tasks, and created on the basis of special microprocessors. The core of such systems is a microprocessor (MP) connected to input devices, e.g. sensors and other communication interfaces, and output devices transmitting control commands to the controlled devices.
An embedded system might be viewed as composed of physical parts – modules. The main component of ES is a digital MP or a kernel performing a programmed processing of digital information. In more complex ES, not one but several or even tens of MPs can be employed. MP is connected to specialized components for collection, measuring, diagnostics and digital processing (encoding, decoding, creating control sygnals), information transmission, etc. MP operates only digital data and cannot interact with peripheral devices until the readings becomes digital information (e.g. temperature, pressure, luminous flux, wind speed), then it is transformed into electric potential (analogous signal) which is transmitted to the converter that coverts analogous signal into digital signal. Digital signal (data) is now suitable to be processed by the digital MP. To process data in the embedded systems, 8-bit, 16-bit, and now even 32-bit MPs are used. The very MPs are not specialized for separate tasks, and are produced for various ES. The above might be called a techno-hardware part– sensors, MPs, controllers, electronic panels, and fittings. Design of this (first) part requires complex specialized equipment and, of course, highly-skilled professionals-technologists.
MP performs data processing and communicates with the surrounding devices according to the encoded algorithms, i.e. special software. Software of EB is a programming code that is prepared in parallel with the hardware, and most often it is designed exclusively to that hardware, i.e. it is not universal and cannot be used with the hardware of other manufacturer. This part of the system does not rely on any high technologies; it only requires a computer, specialized software and well-prepared professionals – resources of intelligence.
Application of embedded systems
ES are used in various areas of modern life and activity ensuring flexibility, efficiency, and functionality of control tasks. ES has a wide range of application areas: from portable devices, e.g. digital clocks, to stationary devices and very large installations, e.g. controllers of manufacturing processes, gas, oil pipelines, power supply protection systems, or systems controlling nuclear power plants, oil refineries, and chemical plants.
Most often, ES are permanently integrated into the hardware of the device as sudetiniai itaisai. Since ES microprocessors are designed only for performing specific defined tasks the design of ES may be simplified (optimized) thus reducing the size, increasing the speed, efficiency, and reliability. Simplicity of ES design allows for mass production thus reducing the costs. On the contrary, ES designed for general-purpose computers, e.g. personal computers, must be flexible, universal, and meet the diverse needs of end-users with lower requirements, dimensions, and system speed.
ES application areas are illustrated by the specific example of ES application below:
Indoor climate control and protection
Automated indoor humidity, heating, ventilation regime maintenance systems use thermostats, light sensors, and humidity sensors (hygrometers) connected into a single network via ES-controlled systems. This allows for more precise and effective control temperature, humidity, and other parameters. Moreover, a premises security system is also connected to this system composed of smoke, motion and window sensors. These may be changed depending on the time of the day, or the time of year. House equipment use wired and wireless networks to control lighting, indoor climate, to make audio and video records, etc. Particularly complex systems are used to protect valuables exhibited in museums: each exhibit item is equipped with a separate sensor.
All these devices use ES for real-time control and collection of data. Talking about premises, usage of complex ES for premise security should be noted. These ES are programmed to assess the seriousness of the situation and possible danger. Depending on the seriousness of the situation, the system either makes a video or audio record, or sends an alarm to security workers, and a signal of a breach of the security system to the owner of the premises via telephone wires or a wireless network (together with the fragments of video record).
Clearly, such a complex system (composed of several or dozens of separate ES, and equipped with sensors) must have a self-contained power supply which could allow for sending data on the dynamics of the situation in the premises to the remote server via wireless network even after the intruder cuts the external power supply. The same system could be used for monitoring fire prevention, local sources of increased heat, amounts of smoke, or carbon monoxide levels. Such systems are also designed in Lithuania, however their demand is higher in the international market.
Transport – navigation
The modern intelligent transport systems, including cars, planes, railway, and ships, are absolutely dependant on ES. Thanks to these systems, contemporary planes (or submarines) can navigate in space in total darkness and without connection to GPS or overground tracking systems (Inertial Guidance System) using the most advanced avionic devices, e.g. integration of the readings of gyroscopes and accelerometers (performed by ES). Due to the progress in the area of ES technologies, the prices for GPS receivers went down to the level where many people use them when picking mushrooms or berries in the forest. And travelling by car in a foreign country this device is irreplaceable by the majority of drivers.
Navigation systems in shipping and aviation help avoiding many accidents, even though they still occur. Today, the controllers of railway, aviation, and maritime transport cannot imagine their work without ES-controlled high-speed communication systems. Maritime transport and port work is coordinated on the global level as every minute of loading/unloading is expensive.
Cars, electric and hybrid (combined) vehicles are also becoming an important application area of ES, where they are used to increase efficiency and reduce pollution.
Other systems using ES that are worth noting are car safety systems, e.g. Traction Control, Automatic Four-Wheel Drive, Anti-lock Braking System, Electronic Stability Control.
To ensure vehicle safety, there are many inexpensive ES-controlled video recording systems that records video material cyclically (within a certain time) offered in the market. In the event of an accident, this kind of material helps resolving the disputes in court. Due to flexible price range, these systems can be used by private car owners, not only by transport companies.
As to freight transport safety means and control systems, we would like to mention ES that are designed by Lithuanian companies and successfully compete in world markets. Based on GPS signals, they controls the position of the vehicle, and calculates the distance travelled with the help of an odometer. In the market, you can also find systems that trace fuel consumption, speed, and accelerometer data, store them, and transmit them to the owner of the vehicle, or a controller. In addition to that, to reduce the accident rate, such systems are used to calculate the distance to the other vehicle in the front, also monitor the condition of the driver (number of rest hours, i.e. whether the driver follows the work-rest regime) as this contribute to the safety of transport systems. There are some systems designed that perform a real-time analysis of the image at the front of the car, and warns the driver of a sudden change in the situation, or a car veering of the road. The data stored are zipped and transferred to the servers via the closest GPS station. In the servers, the data are statistically processed, analyzed and evaluated using specialized applications: after the assessment of drivers’ quality of work, driving manners of specific drivers, and respective fuel consumption rates, this might be used for optimum distribution of tasks for the drivers depending on the significance of the cargo, and the complexity of the route. As the data are transmitted on a regular basis, this makes the work of searching for a missing vehicle easier. Such systems are quite popular abroad, and the growing demand is observed in Lithuania.