Indholdsfortegnelse for Issue 8 i Raspberry Pi Coding & Projects The Complete Manual

Raspberry Pi 2 Model B Raspberry Pi 1 Model B+ The older Raspberry Pi 2 model can still be found on sale. It has the same form factor as the Raspberry Pi 3 with 4 USB Ports, Ethernet connection and Micro USB. It may look the same but it has a slower 900 MHZ quad-core ARM Cortex-A7 CPU and 1GB RAM. This brings it close in line to many low-end desktop computers. Complicating matters slightly is the existence of a Raspberry Pi Model 1 B+, which is identical in layout to the Raspberry Pi Model 2 but with an even slower ARMv6 700MHz processor. If you are confused which type you own then type cat/proc/cpuinfo at the command line. If it lists four ARMv7 processors you are using a Raspberry…

The Raspberry Pi 5 has totally changed the game! There are two versions, one with 4GB and one with 8GB of RAM. The processor is a quadcore Arm Cortex-A76 running at 2.4GHz, which is faster than the chip in the Raspberry Pi 4. And guess what? There’s a power button on the board! No more fiddling with the mains or pulling the power lead out of the USB-C socket. Just press a button and you’re good to go. The button is on the front of the computer, opposite the Ethernet and USB ports. So, if you have an old Raspberry Pi 4 case, you’ll need to get a new one that’s specifically designed for the Pi 5. The Raspberry Pi Foundation already sells them, and other companies will probably make…

The Pi Pico 2 may be small, but it packs a decent punch. With it you can expand your electronics projects, and incorporate a whole new level of functionality that you weren’t able to before with the traditional Raspberry Pi units. micro-USB B Port The Pi Pico’s micro-USB B provides both power, as well as communications between the Pico and a Raspberry Pi or other computer. Here you’ll be able to upload programs and projects on to your Pico. Boot Selection Switch The small button labelled BOOTSEL, Boot Selection, will switch the Pico between two start-up states enabling you to access the Pico as a storage device on your computer or Raspberry Pi. Memory & Storage The Pico 2 comes with 520KB on-chip SRAM memory, as well as 4MB Flash…

ASK AROUND The kit list required to set up a Raspberry Pi is pretty basic: keyboard, mouse, HDMI monitor, SD Card and an optional case. Many of these items you’ll already have, but don’t rush out and buy those you don’t. Ask around to see if anybody you know has spares. STEP 1 The most important thing you need is an SD Card. These are the storage cards commonly found in digital cameras. All modern Raspberry Pi boards, including the Raspberry Pi 3 and Pi Zero, use Micro SD cards but the older boards may use a larger SD Card. STEP 2 The SD Card plugs into the SD Card socket. On the Raspberry Pi 4, 3, and Pi Zero, you push the card in and pull it out. On…

USING TERMINAL Despite its graphical PIXEL interface, Raspberry Pi OS is a Linux operating system and this means you’ll spend a lot of time working with text commands. Using the command line is an important part of learning to use a Raspberry Pi computer. STEP 1 By default the Raspberry Pi boots directly into the PIXEL interface. Here you use a visual metaphor, files, buttons and so on, to make changes to your computer. The command line is where you control a computer by entering text commands. Click Terminal in the Menu bar to view the console. STEP 2 You can enter commands into the Terminal to make changes to the computer. This works alongside the PIXEL interface. Enter: mkdir Desktop/testfolder and press return. Notice a new folder appears below…

VIEWING AND MOVING FILES You can move, manage and delete files using the Command Line but like all modern operating systems Raspberry Pi OS has a program to help you manage your files. Discover how to use the File Manager app. STEP 1 Raspberry Pi OS includes a great file management program called “File Manager PCManFM” or just “File Manager” for short. Click on the FileManager PCManFM icon in the Launch Bar or choose Menu > Accessories > File Manager. STEP 2 File Manager displays the folders in your Home folder (this should match your user name, ‘Pi’ by default). By default you should have Desktop, Documents, Downloads, Music, Pictures, Public, python_games, Scratch and folders. Double-click any folder to open it and view its contents. Click the Parent Folder icon…

STARTING PYTHON For those using the Pi 4 and new Raspberry Pi OS, drop into a Terminal and enter: sudo apt-get install idle3. Older versions of Raspberry Pi OS already have the official Python Thonny pre-installed. STEP 1 With the Raspberry Pi OS desktop loaded, click on the Menu button followed by Programming > Python 3 (Thonny). This will open the Python 3 Shell. Windows and Mac users can find the Python 3 Thonny Shell from within the Windows Start button menu and via Finder. STEP 2 The Shell is where you can enter code and see the responses and output of code you’ve programmed into Python. This is a kind of sandbox, where you’re able to try out some simple code and processes. STEP 3 For example, in the Shell…

COMMAND THE CODE Using the code we created in the previous tutorial, the one we named hello.py, let’s see how you can run code that was made in the GUI at the command line level. STEP 1 Python, in Linux, comes with two possible ways of executing code via the command line. One of the ways is with Python 2, whilst the other uses the Python 3 libraries and so on. First though, drop into the command line or Terminal on your operating system. STEP 2 Just as before, we’re using a Raspberry Pi: Windows users will need to click the Start button and search for CMD, then click the Command Line returned search; and macOS users can get access to their command line by clicking Go > Utilities >…

VARIOUS VARIABLES You’ll be working with the Python 3 IDLE Shell in this tutorial. If you haven’t already, open Python 3 or close down the previous IDLE Shell to clear up any old code. STEP 1 In some programming languages you’re required to use a dollar sign to denote a string, which is a variable made up of multiple characters, such as a name of a person. In Python this isn’t necessary. For example, in the Shell enter: name=”David Hayward” (or use your own name, unless you’re also called David Hayward). STEP 2 You can check the type of variable in use by issuing the type () command, placing the name of the variable inside the brackets. In our example, this would be: type (name). Add a new string variable:…

FASTER AND CONNECTED There’s a lot to like about the Raspberry Pi 4: Up to 8GB of on-board memory, a faster quad-core CPU, support for dual 4K displays via a pair of micro-HDMI ports, and more. Let’s take a look at the Pi 4, and see what it’s got under-the-hood. PRICING Since the Raspberry Pi 4 now offers three different versions within the new model, it stands to reason that the pricing for it has changed slightly. The 1GB memory version of the Pi 4 is priced at around £34, depending on where you shop. The 2GB memory version is on sale for around £44, while the top-end, 4GB memory version will set you back in the region of £54. Together with the cost of the Pi itself, you will…

FASTER AND CONNECTED There’s a lot to like about the Pi 500: with a modified Raspberry Pi 5 under the hood, up to 8GB of on-board memory, a faster quad-core CPU, support for dual 4K displays via a pair of micro-HDMI ports, and more. Let’s take a look at the Pi 500, and see what it’s got under-the-hood. Regional Keyboard The Pi 500’s keyboard is available in the following regions: UK, and US. 1x USB 2.0 Port The inclusion of this legacy USB 2.0 port adds further compatibility with storage devices. 2x USB 3.0 Ports There are two fast USB 3.0 ports available on the rear of the Pi 500, so you can attach projects, as well as game controllers and other such devices. microSD Card Slot The microSD Card…

The Pico is something entirely different from the Raspberry Pi Foundation’s usual releases. Whereas the Raspberry Pi, now on version 4, is a small computer, and even the Compute Module and the Pi 400 are still just computers, the Pico is actually a microcontroller. A microcontroller is a processing unit that’s designed to work with programmable peripherals, and has input and output modules alongside a small amount of memory and storage capabilities. The processors are often scaled down, compared to the processor on a Raspberry Pi, or even inside your desktop computer, but powerful enough to complete basic tasks. Examples of a microcontroller in action can be found inside a washing machine, or traffic lights. A washing machine has no need for a quad-core processor, 8GB of memory, and the…

POWERING THE PI The Raspberry Pi OS OS has been powering the Raspberry Pi since its release back in 2013. At its core, Raspberry Pi OS is a Linux operating system, based on the hugely popular Debian flavour of Linux. Mike Thompson and Peter Green created Raspberry Pi OS in 2012, to work on the low-performance ARM CPUs found in the early Pi models. Toward the end of 2014, Raspberry Pi OS was further improved to work on the then new model Pi, the Raspberry Pi 2; utilising the 3.18 Linux kernel while still having Debian 7 (codenamed Wheezy) as the base. Mid-way through 2015, Raspberry Pi OS started using Debian 8 (Jessie) as the base, with kernels 4.1, 4.4, and 4.9. Kernel 4.9 was also used from 2017’s Raspberry…

Modern artificial intelligence (AI) coding tools go much further than checking your syntax, and helping you debug your programs. AI tools can analyse your entire code, offer suggestions of what to do next, work out where your program should go next and more. Don’t expect them to replace a good coder – they won’t write your code for you. But clever use of AI tools can greatly reduce the time it takes to complete your programs, by identifying problems so you can nip them in the bud and producing coding solutions that would take a human coder hours to write. But what are these tools? GITHUB COPILOT From free, https://github.com/features/copilot If you’re scratching your head wondering what to do next with your program, you can ask GitHub Copilot a question.…

GET TO KNOW GIMP Your Raspberry Pi can display images with its built-in Image View app but for any image editing you’ll need GIMP (GNU Image Manipulation Program). GIMP is a powerful software package for photo editing and is a great tool to install on your Raspberry Pi. STEP 1 Open terminal and enter: sudo apt install gimp to download and install the GIMP package. An alert will appear saying: “after this operation, 117 MB of additional disk space will be used. Do you want to continue [Y/n]?” Enter: y and press Return. GIMP will now be installed in Raspberry Pi OS. GIMP is a lot larger than most programs you’ll install, so the installation takes STEP 2 When the installation has completed you will find GIMP under Menu >…

IT’S ALL MATHS, MAN You can get some really impressive results with the mathematical powers of Python; as with most, if not all, programming languages, maths is the driving force behind the code. STEP 1 Open up the GUI version of Python 3, as mentioned you can use either the Shell or the Editor. For the time being, you’re going to use the Shell just to warm our maths muscle, which we believe is a small gland located at the back of the brain (or not). STEP 2 In the Shell enter the following: You can see that Python can handle some quite large numbers. STEP 3 You can use all the usual mathematical operations: divide, multiply, brackets and so on. Practise with a few, for example: STEP 4 You’ve…

MASTERING MODULES Think of modules as an extension that’s imported into your Python code to enhance and extend its capabilities. There are countless modules available and as we’ve seen, you can even make your own. STEP 1 Although good, the built-in functions within Python are limited. The use of modules, however, allows us to make more sophisticated programs. As you are aware, modules are Python scripts that are imported, such as import math. STEP 2 Some modules, especially on the Raspberry Pi, are included by default, the Math module being a prime example. Sadly, other modules aren’t always available. A good example on non-Pi platforms is the Pygame module, which contains many functions to help create games. Try: import pygame. STEP 3 The result is an error in the IDLE…

HAT & GPIO Interface The Raspberry Pi is made with expansion in mind. External peripherals and items are often attached here. ‘HAT’ stands for Hardware Attached on Top’, which is where many things connected to the Pi sit, and GPIO is ‘General Purpose In/Out’, which refers to the data flow from and to the Pi. Powerful CPU The Raspberry Pi 5 is powered by a 64-bit quad-core Arm Cortex-A76 processor running at 2.4GHz, giving a performance boost of between two and three times what the Raspberry Pi 4 could achieve. It also has a Broadcom VideoCore VII GPU. Power Button With previous Raspberry Pi models, to turn it off and turn it on again you had to pull the power lead out or switch it off at the mains. At…

Inside the Pi 400 is a modified Raspberry Pi 4. It’s longer, spanning the width of the keyboard, with a large heatsink to dissipate enough heat for the overclocked processor. The Pi 4’s communication ports are spaced along the back of the Pi 400 keyboard, minus a second USB 2.0 port and a 3.5mm audio jack. 40-Pin GPIO The slightly recessed GPIO port is directly connected to the Pi 400 board inside the keyboard. This means you can still attach the usual Raspberry Pi HATs and other devices as you would a bare-metal Raspberry Pi. What’s Inside? This internal view shows the placement of the Pi board. microSD Card Slot The microSD Card Slot is where you’ll insert the card that contains the Raspberry Pi OS – or any other…

The Pico uses MicroPython or C/C++ code in order to communicate with the devices it will be attached to. The code will, when uploaded to the Pico, run a specific set of instructions depending on the electronics that are soldered to the Pico. For example, in MicroPython, with an LED attached to the Pico, you would initialise and import the Pin and Timer modules, tell the Pico which GPIO the LED is attached to, then setup a routine that will use the Timer function to send a signal to the LED – let’s say every couple of seconds. The end result would be a blinking LED, which goes on and off every two seconds. Naturally, the more complex the electronics attached to the Pico are, then the more complex the…

THE POWER OF PI With many different versions across four generations of models, the Raspberry Pi is certainly a busy little board. But while each Pi offers something slightly different, for the newcomer it’s a confusing medley of hardware specifications and model numbers. Which, Raspberry Pi hardware, then is going to be best for you? Naturally, that questions depends greatly on what it is you want to do with your Raspberry Pi. If you have a particular project in mind, such as a home media centre server, then you’d probably opt for the more powerful and hardware-capable model of Raspberry Pi. If you want to setup a wireless security camera project, using the Raspberry Pi as the core hardware, then perhaps the Pi Zero W would be a better fit.…

PIXEL PIXEL stands for “Pi Improved Xwindow Environment, Lightweight”. It’s a lightning fast and energy saving desktop that looks good too. It contains almost everything you’ll ever need to work with the Pi. THE DESKTOP The PIXEL interface is a module that’s installed on top of the core OS. It has seen some improvements over the years, and with the release of the Pi 4 and Raspberry Pi OS Buster, it now looks like this. THE PROGRAMS The programs that come pre-installed with Raspberry Pi OS are easily located by clicking on the Raspberry Pi logo in the upper left corner of the desktop. Once there, you can select from the sub-menu categories, followed by the program name. PRODUCTIVITY You’ll notice that within the Main menu, there’s a category named…

ADVANCED PACKAGING TOOL Add / Remove Software is great for finding and installing software but most of the time you manage apps on a Raspberry Pi using a program called APT (Advanced Packaging Tool) using the apt command. STEP 1 To manage the apps on your Raspberry Pi you’ll need to use a tool included with Raspberry Pi OS called APT (Advanced Packaging Tool). APT is a command line tool so you need to either start your Raspberry Pi in the command line or click on the Terminal icon. STEP 2 The command used to control packages in Raspberry Pi OS is apt Type apt into the terminal and press Return to get a description of what the app does. The instructions tell us that the “most frequently used commands…

EDITING CODE You will eventually reach a point where you have to move on from inputting single lines of code into the Shell. Instead, the IDLE Editor will allow you to save and execute your Python code. STEP 1 First, open the Python IDLE Shell and when it’s up, click on File > New File. This will open a new window with Untitled as its name. This is the Python IDLE Editor and within it you can enter the code needed to create your future programs. STEP 2 The IDLE Editor is, for all intents and purposes, a simple text editor with Python features, colour coding and so on; much in the same vein as Sublime. You enter code as you would within the Shell, so taking an example from…

FUNKY FUNCTIONS A function is a command that you enter into Python to do something. It’s a little piece of self-contained code that takes data, works on it and then returns the result. STEP 1 It’s not just data that a function works on. They can do all manner of useful things in Python, such as sort data, change items from one format to another and check the length or type of items. Basically, a function is a short word that’s followed by brackets. For example, len(), list() or type(). STEP 2 A function takes data, usually a variable, works on it depending on what the function is programmed to do and returns the end value. The data being worked on goes inside the brackets, so if you wanted to…