Power of Pi

What is a Raspberry Pi? Douglas Keywood sets up this tiny £30 computer and looks at what it can do. We used it in conjunction with a Cirrus Logic audio card - see Audio Pi.

The Raspberry Pi is a small, low-powered, credit card sized computer that plugs into any HDMI equipped monitor and uses a regular keyboard and mouse, connected via USB. It was designed with children and coding amateurs in mind, although we are looking at what it does with audio – its entertainment functions if you like. 

   This aside for a moment, one of the Pi’s main functions and goals is to teach children, teens and programming amateurs the basic and also more complex sides of coding and computer programming with Python, Scratch and Wolfram (which is more advanced). This makes Raspberry Pi ideal for use in schools where its prime function is to run educational software for those who are learning to code and programme, and at a price point of £29.99 the Pi is cheap enough for wide use in primary and secondary schools. It is also suitably durable too.

   In essence Raspberry Pi is capable of performing the everyday functions of a standard computer, such as watching HD video, playing music and browsing the web. However, due to the fact that the most recent Pi 2 Model B’s hardware isn’t very powerful (despite being the most powerful Pi to date) I found that there are limitations to how the Pi can be used, such as not being able to run regular OSs’ such as Windows 7 and 8. But it is able to run specially designed OSs’ such as Rasperian, its own OS, a variation of Linux, as well as other Linux variants and even, at a later date, Windows 10, although probably in simplified form. 

   The Pi sports a 900 MHz quad-core ARM Cortex-A7 CPU with 1GB or DDR2 RAM hard wired on-board. For memory it uses a micro SD card which differs from its earlier counterparts which used regular SD cards; note the absence of hard disc storage. The Raspberry Pi circuit board also possesses a full HDMI port, ethernet port, 3.5 mm audio jack and composite video – note I am not talking about the Cirrus Logic audio board here.

   Raspberry Pi is immensely powerful for its size, but also for its price. Having previous experience building computers and a good understanding of computer hardware, I found the Pi incredibly easy to build; it could be built by even the most inept and inexperienced builder as all that is required is the plugging in of a few cables and pins. This sort-of makes the Pi ideal as a first computer for a young child or teen, as well as for larger use in schools. As a 15-year-old moving on to sixth form I could see the potential benefits of Pi in teaching computing and programming to a generation that is largely disinterested in the subject. 

   Although the Raspberry Pi OS comes with pre-installed software like Python to teach coding and programming, a ‘Pi Store’ offers further learning programmes at both beginner and more advanced levels. The store also offers games, development tools and apps to expand the uses of the Pi. The Pi OS also comes with its own Epiphany web browser and is capable of wi-fi connectivity by using a wi-fi dongle.

Raspberry Pi uses a Broadcom ARM processor. It needs very little power

so runs cool – eliminating heat sinks, noisy fans and all.

However, despite the fact that the Pi is impressively powerful for its size and price, it’s certainly no super computer when compared to average, ‘grown up’ computers. The Pi’s 1GB of DDR2 RAM instead of the DDR3 RAM most computers use today and the 900 MHz CPU are far slower compared to the 2.4 GHz CPU’s which are the minimum speed for todays average computers. Furthermore the Pi can only run videos up to 720p resolution and I found that both the browser and the Pi itself can be quite slow at times. As a result, I sometimes found myself becoming slightly impatient with the Pi. 

   In an era where everything is instant and loads at the left click of a mouse, the Pi looks tardy.  But on the plus side, I found that in comparison with standard operating systems (Windows and Mac) Pi’s visually simple user interface (UI) makes it easier to understand and handle by younger users. 

The tiny Raspberry Pi board bristles with connectors. At left is an HDMI

socket for a monitor screen and just right of it a small black 3.5mm headphone jack.

The large block at front is an RJ45 socket for ethernet and to its right sit four USB sockets.

At rear are the pins that accept the audio board's socket. 

Once you get a Pi you need to load the ‘NOOBS’ OS onto your chosen SD card. To learn how to do this I suggest you watch a step by step walkthrough: go to Raspberrypi.org and go to the downloads section then click on NOOBS. 

   The Cirrus Logic audio card drivers also need to be installed after the NOOBS OS;  without the drivers the card won’t work. 

   To install the drivers you will need to visit the element14 website and find the Cirrus Logic audio card then click ‘software download’ and the drivers will automatically install to your computer. 

Unfortunately, you won’t be able to simply copy and paste the software file over. On the same page from which you downloaded the software, there is a user manual and it has instructions on how to install the drivers to your SD card. 

   Once all the software is installed and the Pi is booted up you will have to go through a simple installation process and then the Pi should be ready to run. 

Once you’re in the Pi, navigation is fairly simple, and similar to that of a standard computer running Windows – and using applications such as those in the Pi store is easy.

The Pi screen desktop looks much like a simplified Mac or PC. It is a

conventional graphical user interface, or GUI, but LXTerminal is close

at hand – and needed.

CONCLUSION

Unfortunately, overall, I found at times the Pi could be frustrating and somewhat impossible. 

Using the Pi requires at least a basic understanding of software and an understanding of command line drive, meaning what command line code is required, as well as typing it in without error. 

Without at least an intermediate level of understanding of computers the Pi can be a frustration, despite being designed to be easy to run.

   One of the most popular uses for the Pi is as a standalone music player for use anywhere where there is a micro-USB connection, such as in the living room or the bedroom. 

Firstly, however, in order to perform this function you must buy an audio card to attach to the Pi. The card I used was the Cirrus Logic audio card, which possesses a 3.5mm jack for headphone output with microphone facility, a digital stereo audio input and output, an onboard power amplifier for directly driving loudspeakers and is capable of rendering HD audio at 24-bit, 192kHz. 

Music can be transported to the Pi using a USB key (memory stick), or by transferring files directly to the micro-SD card. 

   The standard Raspberry Pi OS has a default music player called LXmusic. However, I found the music player both basic and simple – and it refused to play the tracks until we fully understood, through experiment – its limited abilities. 

   However, other music players exist,  created to enhance Raspberry Pi as a music player, the most notable being PiMusicBox and RuneAudio. 

RuneAudio and PiMusicBox are free – open source software that enable you to turn the Pi into a dedicated hi-fi music player to replace the personal computer, with a smaller, low power, quiet board. 

One of the main purposes of this software is to get the best possible sound quality out of the Pi by optimising the Pi for the best performance.  There's plenty to experiment with, making this absorbing if you like computers.

   Various external cards are available too, including audio cards.

We used Raspberry Pi in conjunction with a Cirrus Logic audio card - see Audio Pi for our review of this card.

For more see...

https://www.raspberrypi.org

http://www.element14.com

Amazon and Maplins also sell Raspberry Pi, Pi kits and accessories.