Types of Computing Devices
There are multiple types of computing devices available today. All devices are usually general purpose devices that need to be instructed or programmed to perform whatever functions are required. They only vary in their physical size, processing power, and user interface. Given their capabilities each device may be better suited for a specific purpose. The most common types of computing devices are described below.
Personal Computers
Personal Computers (PCs) are the most commonly used general purpose computing devices in homes, academic instututions, and organizations for a wide range of tasks from gaming to financial computations. They have mid-range processing power but are very user-friendly, affordable, and compact in size. There are two versions of PCs, the Desktop and the Laptop.
Desktops are larger and heavier than laptops and need a separate display screen known as a monitor. They are therefore used in a fixed location such as an office or home desk. Laptops are smaller, lighter, and have a display screen attached. They can therefore be carried around and used from multiple locations.
Servers
Servers are high-powered computing devices and used where extremely complex processing is required. Quite often, a computing set up will have multiple personal computers for the end-users all connected to a server where the main processing is done. Servers are often designed to not only have more processing power but to me nore reliable, which makes them more expensive than PCs. Servers are generally intended for fixed-location use and are not designed to be portable.
Single Board Computers
PCs and Servers are assembled as a set of independent components each for a specific function, such as microprocessors, memory, network support, and input and output (I/O) peripheral interfaces, all connected by cables. Single-board computers in contrast have all these components assembled on a single circuit board.
Single-board computers were made possible by increasing the density of integrated circuits such that all components required for a computer could fit on a single circuit board. Because of this denser integration of components, the number of components and connectors between components is reduced, and SBCs are often smaller, lighter, more power-efficient, and robust compared to multi-board computers.
The benefit of an SBC is its compact size and ruggedness since connectors between components can be easily damaged or get disconnected. The limitation of SBCs is that they are not customizable or expandable for individual features, such as memory. In terms of maintainability, in multi-board computers, if one circuit board malfunctions and cannot be easily repaired, it can be replaced with a new circuit board quite easily. With an SBC, the entire board will need to be replaced if it cannot be easily repaired.
SBCs are preferred over multi-board computers for prototyping systems where low cost, size, and power consumption are more important than high processing power or memory. One of the most popular SBCs is the Raspberry Pi.
The Raspberry Pi
The Raspberry Pi is a single-board computer developed in the United Kingdom by the Raspberry Pi Foundation with the idea to make it easier to teach and learn basic computer science in schools. Its low cost, compact size, and portability make it ideal for teaching computing concepts, like programming, networking, and use as processors in IoT and robotics projects.
The Raspberry Pi does not come with the peripherals (keyboard and monitor) required to provide inputs and view outputs. The same peripherals that work with any personal computer can be used with the Raspberry Pi.
What is unusual about the Raspberry Pi is that it does not come with any permanent storage. It uses a removable SD (Secure Digital) card, which is a non-volatile memory card that can be plugged into the SD card slot. The Raspberry Pi uses the SD card to run both the operating system and store data if required.
A Raspberry Pi can be thought of as the equivalent of a small computer and an experimental Arduino board combined. Using it as a computer, you can run the Arduino IDE on it and program your boards. You can also run other software you need for your IoT projects, such as Node-RED or even a MongoDB database on the Raspberry Pi. It is, therefore, a good alternative to a laptop or a desktop as it is cheaper and smaller. The only challenge is that it only runs a variant of Linux, so it is not as easy to use as Windows or macOS.
Using it as an experimental microprocessor, you can connect sensors directly to the Raspberry Pi and write programs (using the Python programming language) to process the data from the sensors and do almost everything you can with an Arduino board. However, Arduino boards are much cheaper than a Raspberry Pi and are available in multiple sizes. If you intend to have multiple distributed sensors, dedicating a Raspberry Pi for each one would be expensive.
If you are comfortable with Linux, an architecture including multiple Arduino boards and one Raspberry Pi as the central data processor and communicator is the most optimal.
Smartphones
Mobile or cellular phones were originally designed to be portable voice communication devices. Cellular networks also primarily supported voice communication. Over the years, with advancements in technology, cellular phones and cellular networks became capable of processing data as well. With this capability, and further evolution in both the phone hardware and software, cellular phones became mini-computing devices that could do almost everything a PC could do. They are now referred to as smartphones and except for their small screen size, which makes data input cumbersome and reading large amounts of data a bit difficult, they are almost as powerful as PCs and can be used for almost any application.