|A Raspberry Pi single-board computer provides basic computing capabilities with the additional of storage memory, a monitor, a keyboard, and a mouse. Photo courtesy of the Raspberry Pi Foundation (www.raspberrypi.org) and Switched On Tech Design (www.sotechdesign.au). |
Raspberry Pi computers were nominally developed for schools and hospitals in Great Britain as low-cost teaching vehicles for students to improve their programming skills. These single-board computers are equipped with a secure digital (SD) memory card socket but no internal memory, and users must supply their own SD memory, among a number of other components, to make a Raspberry Pi computer functional. But as schools, students, and many businesses have found, once they are powered up, these tiny computers can be quite useful for a number of tasks, in addition to teaching programming.
A Raspberry Pi computer is not equipped with a real-time clock, but relies on the clock from a related system application, such as a network time server. The single-board computer does include an inter-integrated-circuit (I2C) interface, which makes it possible to add a real-time clock to a Raspberry Pi. Several Raspberry Pi computer versions are currently being offered by several suppliers, including Amazon (www.amazon.com), Allied Electronics (www.alliedelec.com), and Newark (www.newark.com). The Model A has a single Universal Serial Bus (USB) port, 256 MB of random-access memory (RAM), and no Ethernet controller; Model B has two USB ports, 512MB of RAM, and a 10/100 Ethernet controller. Both models include an HDMI connection, an audio jack, and an RCA video jack.
Tiny Computer, Tiny Price
For most customers, it is the price of these microcomputers that is immediately so attention-getting, at about $35 to $40 each. As noted, memory must be supplied, as well as numerous other computer components, including a high-definition-multimedia-interface (HDMI) monitor, a power supply, a USB mouse and keyboard, and even an operating system. An important requirement for the Raspberry Pi is the USB power supply, which is specified for at least 700 mA current at +5 VDC to ensure stable operation. For safety and reliability, it is also wise to add some form of a case around the single-board computer for protection. Once properly equipped, these little single-board computers can perform many of the tasks of full-sized computers, including spreadsheets, word-processing, and playing games, and they can also display high-definition video with a compatible monitor.
Where did the Raspberry Pi computer come from? It is the creation of the Raspberry Pi Foundation, a charitable organization founded in 2009 to promote the study of basic computer science, and introducing the first Raspberry Pi computers in 2011. More specifically, the Raspberry Pi computer is the brainchild of Eben Upton, who had earned a PhD from the UK's University of Cambridge and with much time spent in the University of Cambridge Computer Laboratory and then teaching at the university before moving on to Broadcom (www.broadcom.com) as Technical Director and ASIC designer, as well as trustee of the Raspberry Pi Foundation. He had noticed what he felt was a serious dropoff in programming skills among computer-scientist students since the 1990s, perhaps due to the increasingly high costs of computers. A goal of the Raspberry Pi Foundation is to make these low-cost single-board computers available to children all around the world, hopefully creating a new generation of programmers.
Free Linux OS
For their low prices, these little computers are quite capable. The single-board computers are based on a low-cost but stable Broadcom BCM2835 system on chip (SoC) which includes a 700MHz 32-bit ARM1176JZF-S microprocessor (about the equivalent of a Pentium 2 microprocessor from Intel Corp.) essentially developed for mobile applications and a VideoCore IV graphics processing unit (GPU). The single-board computers can run the Linux operating system (OS), which is a free and secure OS, and provide enough processing power for most basic computing tasks.
Because these small credit-card-size computers are susceptible to external discharges if they come in contact with conductive metal strips, many Raspberry Pi owners also invest in a case of some kind, such as the case produced by Bud Industries (www.budind.com). The Bud "Pi Sandwich" case is formed of two identical halves and has windows on all four sides for easy access to the microcomputer's various ports, such as its audio, video, and USB connections. As reported in an earlier issue of U.S. Tech, this case is a patented design with oversized windows, for use with future versions of Raspberry Pi computer boards in which port locations may change or new ports may be added. Without cutting additional holes in the "Pi Sandwich" case, flat cable connectors can be used to attach a liquid-crystal-display (LCD) screen or keyboard to a Raspberry Pi while using the normal I/O ports for other functions.
Allied Electronics and Newark have made arrangements with the Raspberry Pi Foundation to be "official" suppliers of these low-cost computers in the United States. The Raspberry Pi computer version selling for $35.00 from Allied Electronics, for example, is based on a Broadcom BCM2835 700MHz ARM1176JZFS processor with floating-point unit (FPU) and Videocore 4 GPU capable of 1 Gpixel/s, 1.5 Gpixel/s, or 24 GFLOPS capabilities. The microcomputer has 512MB RAM, 10/100 BaseT Ethernet ports, two USB 2.0 sockets, an HDMI socket, an SD card socket, an RCA video socket, a 3.5-mm audio output jack, and a header footprint for a camera connection. It boots from an SD card, running the Fedora (www.fedoraproject.org) version of the Linux OS. The computer measures just 85.6 x 53.98 x 17mm (3.970 x 2.1 x 0.66-in.). Similarly, in the United Kingdom, Raspberry Pi is going into mass production through licensed manufacturing deals with Premier Farnell's Element14 (www.element14.com) and RS Electronics (uk.rs-online.com).
Some companies support the need for the additional computer components needed with a Raspberry Pi computer, such as Mouser Electronics (www.mouser.com) with display modules. Some of the company's display modules, based on thin-film-transistor (TFT) liquid-crystal-display (LCD) technology, have been developed specifically for use with the Raspberry Pi. Each module has a comprehensive range of serial commands ready to be received from the tiny computer, to draw primitives such as lines, rectangles, circles, and text, to display images, play sound, and log data to a microSD card.
Where Do Businesses Come In?
As the availability of these low-cost computers increases, they are certain to have a growing impact on the small-to-medium-sized-business (SMB) sector. Raspberry Pi is quite effective for programming displays for digital signage, for example. It provides enough processing power for generic industrial and control processes, such as collecting data in a factory environment. It is readily customizable for a small business's needs. For some SMB applications, it can be used as a server to handle light communications traffic. In addition, it can be used by smaller companies for penetration testing of information security.
A growing number of small companies are using Raspberry Pi as a dashboard for business intelligence, and it can be deployed as a low-cost development platform for both software developers and network engineers when developing applications solutions. The Raspberry Pi computer works with the Python (www.python.org) programming language, which runs on a variety of operating systems, including Windows, Linux/Unix, and the Apple Mac OS X, and is free to use, even for commercial products, because of its OSI-approved open-source license. The programming language is relatively easy to learn, but quite capable and powerful, especially when teamed with a low-cost single-board computer such as the Raspberry Pi.