For children of the 1980s, the Raspberry Pi rekindled a flame that recently fluttered when ZX Spectrums and Commodore 64S dominated the world.And that was also wanted!Engineers like Upton recognized that interest in programming decreased with the rise of the not programmable game consoles.The Raspberry Pi, a passionate project, is today the best -selling computer of all time in the UK.If you want to find out what it is all about and which version is the best for you, read on!
Why was the Raspberry Pi developed?
In less than 10 years, the Raspberry Pi has become Lingua Franca of bastlers and professional electronics technicians. This checks-sized computer, which is driven by an ARM processor, has gone through several iterations that also produced a reduced version. With over 40 million units sold  (2021), he became the best -selling computer in Great Britain in 2015 . The record that he broke was held by Sinclair ZX Spectrum , a black box with rubber tag that contributed to the home computing revolution of the 1980s. And to understand why this happened at all, it is necessary to look back on the decade of the childhood of his creator. People like Upton  The question of what led to the lack of programming competent students interested in engineering (Figure 1). Like many children born in the 1970s, the 1980s' home computing boom. With 8-bit processors such as the Z80 and the 6502, computers were built that were cheap enough for private acquisition. The most critical element, however, was that the user was confronted with a flashing cursor when switching on: no windows, no mouse, no starting sound. It was the responsibility of the user to decide what he wanted to do next. Many invited a game from a cassette, which at least required the Load command. But at some point, many decided to turn to programming these devices, with the programming language that supported each of these devices: basic.
This "Sweet Spot" in computer history was crucial for the start of the careers of many today's engineers.In the 1990s, the game consoles from Nintendo and Sega were aimed at those who just wanted to play.Due to their business model, their consoles were designed in such a way that they could not be programmed by the user.If you wanted to write a game, you needed special tools from the manufacturer of the console .Similarly, with the advent of the PCs and the Windows operating system, the need to program so that the computer did what you wanted, in the background, which led to a generation of users and not programmers. It seemed clear,That today's children would need access to the type of accessible, programmable computers that had just experienced in his childhood if one wanted to fight the MINT deficiency.
The Raspberry Pi is born
Initially played around with an Atmel Atmega644, similar to how it started with the Arduino . However, the challenge of microcontrollers is that you need a computer to program it, and C/C ++ is not the simplest programming language that you can learn as a beginner or teach as a teacher. The goal was to introduce a computer that could be used in schools, similar to the BBC Micro, with which the students in British schools grew up in the 1980s . These had been included in the curriculum to impart programming and IT skills. The Raspberry Pi should be able to do the same. Programming and computer technology had also developed significantly since the 1980s. While BBC Micros were connected to each other via Econet , today's future programmers would need an internet connection. And programming languages do not necessarily have to be written; Graphic programming tools such as Scratch provide the necessary basics for young learners without having to deal with the grammar of a programming language. The most important thing was the price that was targeted at $ 35. The aim was to put a reasonable amount of computer performance in the hands of the people who would make the loss bearable in the event of a defect. As a Broadcom employee at the time, potential saw potential in a new compact, powerful arm-based system-on-chip (SoC), the BCM2835. With an integrated graphics unit (GPU) and the periphery (USB) common in PCs, it seemed to be the ideal starting point. However, the design of the first Alpha version was around $ 110 far from the target price. Further optimization rounds, such as B. the implementation of audio via a pulse -wide modulated (PWM) output instead of a dedicated audio chip brought down the total costs. Perhaps the best feature of the Raspberry Pi, the GPIO header, was added at that time, which suddenly was able to control engines and interact with peripheral devices.
What can a Raspberry Pi?
Since its introduction, the check-sized Raspberry Pi has not demanded little to its user, which not every PC and smartphone owners already has. The board can be supplied with electricity via a smartphone charger (although the performance requirements of the latest designs require somewhat more violent versions). Mouse and keyboard are connected via USB, a monitor can be connected via the HDMI interface. The first generation boards also supported a composite video output, but it was out of date with the introduction of the second generation. There are a number of Linux-based operating systems (OS) that must first be written on an SD card, whereby Prepared SD cards are also available. The initial OS was Raspian (now called Raspberry Pi Os), a Debian-based distribution that has recently been supplemented by Ubuntu. Microsoft also offers Windows IoT Core, a slim Windows that aims at Internet-of-Things applications. There is also support for RISC OS, which was originally created for the arm-based Archimedes computer, followed by the BBC Micro, and media center system distributions such as Libreelec.The full image of the Raspberry Pi OS contains a series of software applications that enable users of all ages. Younger users who want to familiarize themselves with programming can use the visual scratch environment. Similar to Logo  From the BBC micro period, simple processes can be described and placed in loops, whereby reactions can also be implemented to simple inputs. Python is also available for those who are looking for a programming language. An exciting, but perhaps often overlooked program is the Sonic Pi  synthesizer, with whose simple programming language can create polyphonic music. After all, Wolfram and Mathematica offer powerful tools to tackle scientific and technical problems with the help of mathematics. The operating system also contains a web browser and a store in which additional programs and apps can be downloaded. A version of Minecraft is also included for game enthusiasts. With Python, the game can also be programmed so that objects can be inserted and manipulated into the blocked 3D world.
Which Raspberry Pi is the right one for me?
In the past 10 years, four different generations of the Raspberry Pi have been presented in check card format.During this time, the amount of storage and the performance of the processor in the SOC have steadily improved.If you are just starting, you should invest in the latest Raspberry Pi-4 models [12,13] (Figure 2).The user experience is better thanks to the faster processor, especially when using the web browser and browser-based applications, such as Node-Red .It also supports two 4K HDMI monitors, has Gigabit Ethernet and dual band WLAN and offers both USB 2.0 and 3.0.With a large selection of housings, the board can be easily and safely integrated with any external circuit with which you want an interface.
If your focus is more on using the Raspberry Pi as an alternative to a classic computer, the new Raspberry Pi 400  is an excellent choice (Figure 3).The computer is integrated into a housing with QWERTZ keyboard, so that only one mouse and a monitor have to be connected to get started.Complete packages also contain a power supply and instructions for commissioning.
Not everyone needs a monitor for their planned application, especially not if you want to integrate a Linux-based machine into something like an industrial machine or a robot.The Raspberry Pi Zero, which was first presented in 2015, is worth considering for such applications.Also available with WLAN , this compact version retains the 40-pin GPIO interface for controlling engines or for communication with I
C- and Spi-Peripherie. In addition, in 2021, the Raspberry Pi Pico was introduced, which, however, detached from the Linux-powered platforms of its predecessors (Figure 4).The PICO has an RP2040 microcontroller that integrates two ARM-Cortex-M0+processors that are not suitable for the execution of Linux.Instead, the PICO can be seen as an alternative to Arduino boards, although its performance for low-end-machine learning (ML) with Tensorflow Lite  is good enough.
How can the skills be expanded?
Thanks to the standardized GPIO header, various hazas and other expansion boards are available to expand the skills of the Raspberry Pi. Comparable to the Shields for Arduino products, they range from simply to complex. Prototyping is simplified with the Joy-IT Protoshield+ , which offers solderable connections, screw clamps and 0.1 "connector strips. The operation of the Raspberry Pi on a battery is simplified with the Joy-IT Strompi3  Widerer voltage entrance area is supported as only 5 V. It not only informs you if the battery source has to be loaded, but also contains a real -time clock (RTC) that enables the Raspberry Pi to keep the correct time even without internet access. Options for those who want to improve the quality of the audio output. The Hifiberry  uses high-quality digital analog converter (DAC) from Burr-Brown and integrates into the ASA mixer control that is used in Linux include relays for home automation and control, CAN and RS-485 interfaces as well as I
C-Breakout boards . On the Raspberry Pi boards there are also two FPC interfaces (flexible printed circuit).One of them supports DSI, a digital video output interface used with LCD panels.A number of sub-ten-tin displays enable the construction of standalone applications such as weather stations or media centers, coupled with touchscreen interfaces.The other interface is a video input for which there is also a number of cameras (Figure 5).With the Raspberry Pi Camera Module V2 , video streaming, time-lapse photography or image recognition can be realized together with ML tools.Infrared cameras are also available for those who want to capture what happens in their garden at night .
Since the Raspberry Pi Foundation does not provide a clear roadmap, we cannot say what the next generation of boards will look like. As a SOC provider, Broadcom is further developing its technology, so that more power will most likely be available by more cores. There is also a good chance that the graphics skills will also receive an upgrade. The storage technology has also developed, so that there may also be a switch to LPDDR5 SRAM. When you read blogs, forums and online articles, the switch to Micro-HDMI seems to have annoyed many people, but it is difficult to see how the replacement can be accommodated in the tiny form factor by full size HDMI connections. Useful upgrade would be the departure from the SD card to UFS memory. Smartphones and to a certain extent the automotive industry are already moving in this direction, so it would be a surprise if Broadcom did not support this. Alternatively, integrated support for an M.2-NVME SSD as a module or soldered package could make hundreds of gigabyte storage space available. Other upgrading options are at Wi-Fi 6, but it is doubtful that such a step would bring users a meaningful benefit. With the increase in mechanical learning algorithms that are used in image processing systems, a board with a kind of AI accelerator would make. Perhaps this should be seen as a sign that a Raspberry Pi 5 will also be equipped with a surprise.