Table of contents for Vol 4 in Raspberry Pi Annual

The Raspberry Pi was first created in 2012, with the intention of making digital creation accessible to all. Since then, more than 14 million units have been sold to adults and children alike. Pis of different kinds are used in classrooms, libraries, research laboratories, and of course, hackerspaces all over the world. Builders, coders and hackers are using this amazing device to create everything from doomsday switches to fruit ripening detectors. In this new Raspberry Pi Annual, we’ll bring you all the basics with step-by-step tutorials in setting up your Pi and advice from Pi pros. We’ll also show you the secrets of Pi interfacing, how to create a virtual reality setup, some exciting Python projects – and much more. Welcome to the Raspberry Pi revolution!…

01 Wire in the switch The first job in interfacing a switch to the Pi is to connect one of the switch’s two terminals to a GPIO pin which will be configured as an input in the software) and connect the other of its terminals to 0V (GND). Having done this, the GPIO pin will be connected to 0V, a condition that the software will see as a logic 0, whenever the switch is closed, ie held down in the case of a push button or in its on’ state with a mechanically latching toggle switch. 02 Add a pull-up resistor Although a GPIO pin wired to a switch and 0V will be at logic when the switch is closed, it be ‘floating’ when it’s open. other words, it wouldn’t…

Interfacing an output device such as an LED to a GPIO pin requires that the device doesn’t require more than 3.3V and it doesn’t draw more than a GPIO pin’s maximum 16mA current. Devices such as electric motors and blue or white LEDs, that require a higher voltage supply and/or draw a higher current, need special treatment. The solution is to use a transistor, which can be thought of as an electronic switch. A small current from a GPIO pin turns the transistor on or off, thereby turning on or off a separate circuit involving a higher voltage and often a higher current than a GPIO pin can supply. This secondary circuit might use the 5V on the GPIO header as its supply but, if a higher voltage is required…

Like it? Not surprisingly, the Venn diagram of nostalgia for Macs and contemporary makery creates an intersection that’s packed with projects. One of Jannis’s favourites is Mans Jonasson’s NESMAC, which is an old Macintosh Classic with a Raspberry Pi inside (https:// youtu.be/ q1APtxbUfg8). Further reading To stay informed about the gifbox and weatherbox project mentioned in the interview, or any Jannis’s projects, head to his website: https:// jann.is. On his Ghost blog you’ll find a complete write-up of the LEGO Macintosh Classic. You can also follow him on Twitter: @ jannis. What inspires your projects? Pretty much all of my side projects are born from scratching an itch. In the past, that has been mostly software – starting with a blogging software called s9y in the early 2000s and more…

Humidity is a measure of how much moisture or water there is in the air. In this tutorial you will use Python to build a real-time humidity display. The program takes and stores a humidity reading using the SenseHAT’s on-board sensor. Then it calculates a simple ratio to determine how many LEDs to turn on. In essence, the higher the humidity the more LEDs are turned on. Then the number of LEDs that need to be turned ‘off’ is calculated and these are added to the list. Finally, you’ll set the program to display and ‘turn on’ the required number of LEDs. The program continually loops so both the reading and LED display is updated as the humidity changes. 01 Attach the SenseHAT Ensuring that your Raspberry Pi is off,…

What you’ll need ■ USB storage device ■ Ethernet cable At some point during the lifetime of your Raspberry Pi, you are likely to encounter a problem with your SD/ microSD card. If you’re lucky, this will be minimal; perhaps a reboot will fix it. If you’re unlucky, it could mean the end of your SD card, and the loss of all data on your Pi, including your latest project. The simple fact is that SD cards do not last forever. Flash storage, by design, has a limited number of read/write cycles. While error-correction software is built-in, and cards ship with larger-than-described storage to cover damaged blocks, eventually corruption will cause a problem. SD card corruption occurs in various ways. It might be due to a sudden variation in voltage…

The biggest advantage of using the Pi at the heart of a desktop-based system is its low cost. But if you want to eke every last drop of performance from it, what do you need to do? The first thing is – of course – to choose the latest Raspberry Pi 3 model as the core of your desktop. It’s the fastest, most powerful Pi yet, and you can squeeze additional power from it through overclocking – setting the processor to a higher speed (we’ll explain more over the next few pages). Overclocking raises the next issue: how can you keep your Pi from overheating? The solution is to add a heatsink. You can purchase these for as little as £1 each from the likes of Pimoroni, but choose carefully:…

Like it? Stefan has two projects on the go: a Pi-based music synthesiser (built into the top of his Hammond organ); he’s also working on improving the aerodynamics of his car for better fuel efficiency and says he’ll “probably end up putting a Pi in there as well…” Further reading Stefan’s recent projects include customised mechanical wristwatches, a remake of an analogue music circuit from the 1970s for an alarm clock and a complete rebuild of the vacuum tube (valve) amplifier in his 1962 Hammond organ. Read more at www.stefanv.com. With this project, Stefan Vorkoetter takes the term ‘Pi hack’ and applies it quite literally to hacking down a Raspberry Pi 3 Model B to the bare essentials required for the job, combining it with a 7-inch display to create…

What you’ll need Minecraft https://www.mojang.com/games Python https://www.python.org McPiFoMo http://rogerthat.co.uk/McPiFoMo.rar Minecraft Turtle http://bit.ly/MinecraftTurtle Block IDs http://bit.ly/minecraft_id_links Hooking directly into Minecraft with Python gives us many advantages, but rather than building by hand, we can use programming techniques such as loops to simplify much of the building process. In this tutorial, we will manipulate the player character’s position and the blocks around them. We use simple lines of code to replicate blocks in rows and columns, to build entire rooms out of thin air. We also teleport Steve or Alex around your world at the drop of a hat. Combining these two functions enables us to have a little fun with TNT to create our own bomber-man. As a prerequisite, we strongly recommend that you download and install McPiFoMo. McPiFoMo includes MCPiPy…

What you’ll need ■ Suitable for all models of Pi (Pi Zero recommended). For security reasons, you need a dedicated Pi for this project. As you’re probably aware, the cryptocurrency Bitcoin can be used to make anonymous and irreversible online payments, similar to hard cash. Bitcoin is a huge leap forward for privacy-minded people, but the fact that it’s a digital currency means that hackers often target owners of Bitcoin software wallets. In this tutorial, we’ll explore a solution using the lightweight Bitcoin Wallet Electrum on the Raspberry Pi. The Pi will host a ‘cold’ wallet which is kept offline at all times. You’ll also set up an online ‘watching’ wallet on another computer so you can see payments as they come in. Payments are only sent by generating a…

What you’ll need Github repository: https://github.com/ alexellis/motephat-alexa Pimoroni mote-phat and accessories (pimoroni.com) Soldering iron, flux and solder In 2016, Amazon brought the Echo (£150) and Echo Dot (£50) devices to the UK market, providing a voice assistant for your home. The Alexa service provides lots of built-in features such as radio and music streaming, creating and editing your shopping lists, weather updates and many other custom skills provided by third parties. Skill builders such as Uber and Capital One publish their skills for the general public, which means they go through a vetting process similar to that of the Apple App Store. For this tutorial, we will be creating an unpublished skill for our own Echo or Echo Dot to control the Pimoroni home lighting kit called Mote. Our skill…

What you’ll need Raspberry Pi 3 8GB SD card Xbox 360 controller Oculus Rift Developer Kit (optional) Virtual Reality is huge now and has come a long way since the concepts and CGI visuals of Stephen King’s Lawnmower Man. It is one of the fastest growing areas of technology and you can now design models, explore new places and play games all within a virtual environment. A professional VR hardware package is expensive and will set you back several hundred pounds. However, it’s possible to emulate the VR setup up using a Raspberry Pi, Python-VRZero and a 3D graphics module, Pi3D. Now, this is purely for fun and learning, so don’t expect huge gaming PC frame rates, although some of the demos do peak at around 25-30 FPS on a…

What you’ll need ■ Raspberry Pi ■ Sense HAT The classic game of Battleships engages you to find and locate your opponent’s ships by launching torpedoes to try to sink their convoy. In part one of this two-part tutorial, you will create a version of the classic game for the Raspberry Pi Sense HAT. When completed, your program creates a random layout of enemy boats, some ammo and mostly water. Use the Sense HAT joystick to select one of 64 locations on the sea (LED matrix). Then press Enter to fire a torpedo. The program makes use of two lists: one to store the location of the enemy ships, ammo and water, and the second to track the location of your ship. When you fire a torpedo, your current position…

What you’ll need ■ Raspberry Pi 3 ■ Bluetooth USB dongle (if using an older Pi model) The Raspberry Pi model 3 saw the introduction of embedded Wi-Fi and Bluetooth capabilities. This now makes it even easier to interact with Bluetooth-enabled devices such as mobile phones, tablets and speakers. The Python programming language supports a range of libraries that enable you to interact, monitor and control various elements of a Bluetooth device. This tutorial combines the Pi’s Bluetooth hardware with Python code to create three simple but useful programs. First, build a short program to search for Bluetooth-enabled devices and return the 12- part address of each device. Once you have obtained the addresses, you can then scan and find Bluetooth services that are available on that particular device. Finally,…

The Raspberry Pi was designed to inject much-needed enthusiasm back into computing and electronics, and thousands of Pi users have showcased amazing and innovative projects that show just how versatile it can really be. Part of this success is down to the Pi’s fundamental design, with its USB ports and GPIO pins encouraging people to interact directly with the Pi to achieve... well, just about anything. Many Pi projects have morphed into something more permanent as crowd-funding campaigns jostle with major manufacturers to provide people with all manner of addons to extend their Pi’s capabilities, without having to design something from scratch. In this roundup we’ve focussed on 20 of our favourite Pi add-ons, all of which enable you to use your Pi in different ways. You’ll find out how…

What you’ll need ■ Raspberry Pi ■ Pimoroni Enviro pHAT Pimoroni makes a wide range of HAT (Hardware Attached on Top) boards for the Raspberry Pi. These boards are designed to be fully compatible with all Raspberry Pi models. Enter the Pi Zero, a super-slim, super-cheap, $4 version of the Pi. In response, Pimoroni created a range of HATs that fit the Pi Zero, called pHATs. This tutorial focuses on the Enviro pHAT, a nifty little board that packs in four different sensors that let you measure temperature, pressure, light levels, colour, acceleration, take a compass heading and retrieve readings from analog inputs. This creates up to ten different variables, making it ideal for monitoring conditions in your house, garage or garden. This tutorial will walk you through the initial…

Resources Raspberry Pi Jumper Jerky Buttons (optional) Pimoroni Speaker pHAT http://bit.ly/ Speaker-pHAT Hammer headers http://bit.ly/ HammerHeaders The Speaker pHAT is the perfect hardware to add a slick and stylish speaker to your Raspberry Pi. Visually, it has the feel of an 80s-style boombox and crams an I2S DAC and mono amplifier, a tiny 8Ω 2W speaker and a 10 LED bar graph all onto one teeny little pHAT. Now you can integrate music, notifications, speech and sound into all your Pi projects. This tutorial begins with a quick walkthrough of the GPIO Zero Python library – an excellent module which boosts a vast range of recipes for input and output devices such as motors, sensors and buttons. Create a simple button or circuit and then use the code from the…

The Pi’s small size and modest power demands make it the perfect candidate for use as a portable device, and thanks to the range of cases, displays and battery power options out there, you can configure it just about any which way you choose. We’ve decided to build our ultimate portable Pi around the official 7-inch touchscreen, but see the box below for alternatives you might want to consider. The official touchscreen costs around £55 from any reputable Pi outlet. You’ll also need to buy a suitable stand and case to attach your Pi to. There are plenty of options; we’ve plumped for the clever SmartiPi Touch case (£20, www.modmypi.com). The touchscreen fits snugly inside, secured by four screws, and there’s a compartment on the back for your Pi too,…

There’s one thing the Pi is brilliant at, and that’s media. Whether you’re looking for an audiophile-friendly music player, a simple set-top box for playing media through your TV, or a full-blown media server for accessing your digital media from anywhere, there’s a Pi capable of delivering what you want. In this section, we’re going to focus our efforts on creating a Pi media server, which will allow you to share all your video, music and photos with your other devices, both at home and further afield. For the purposes of this project, we’ll focus on the Raspberry Pi 3, largely because it delivers enough oomph to run a media server comfortably. But there are other benefits too – the Wi-Fi, in case you don’t want to site it next…

We’re still waiting for a single Internet of Things standard to emerge, and chances are it never will. In the meantime, each time you purchase a piece of IoT kit from one manufacturer, be it a motion sensor, security camera or smart lighting, you’re gambling that it will not only work with your current ecosystem but also prove flexible enough to work with others should the horse you’re currently backing fall out of favour. And let’s not talk about updates that break compatibility with older devices, eh SmartThings? Services like https://ifttt.com go a long way to helping bridge the digital divide between devices, but why rely on a manufacturer’s piece of expensive kit when you can custom-build your own versatile IoT gadgets using a Pi or Pi Zero? In this…

What you’ll need ■ Minecraft http://www.mojang.com/games ■ Python https://www.python.org ■ McPiFoMo http://rogerthat.co.uk/McPiFoMo.rar Sometimes, Minecraft can seem far more than just a game. It’s an incredibly creative tool and with the use of Redstone and Command Blocks you can produce some amazing worlds. We’re taking things a step further by enabling you to plug Python code directly into Minecraft. What you do with it is completely up to your imagination! MCPiPy was developed by ‘fleap’ and ‘bluepillRabbit’ of https://mcpipy.wordpress.com, to connect MineCraft Pi Edition with Python on the Raspberry Pi, using open APIs. However, with the use of Forge we have put together a package that enables the use of Python in retail Minecraft. We’re using Raspberry Jam developed by Alexander Pruss, a Forge mod for Minecraft which implements most of…

Resources Minecraft www.mojang.com/ games/ Wireshark www.wireshark.org Python www.python.org McPiFoMo http://rogerthat.co.uk/McPiFoMo.rar Block IDs http://minecraft-ids.grahamedgecombe.com Creating pixel art in Minecraft can be quite therapeutic, but placing the blocks down one-by-one can also be incredibly time-consuming. However, by using Python and a handy little ‘for’ loop or two, we can create scripts to automatically build prefabricated pixel art directly into our Minecraft worlds. If you’re using Minecraft Pi edition on a Raspberry Pi, no additional software is necessary. We’ve also put together a number of tools to ensure this hack works on Linux, with a retail version of Minecraft. Therefore as a prerequisite, we strongly recommend that you install McPiFoMo. McPiFoMo includes MCPiPy by ‘fleap’ and ‘bluepillRabbit’ of MCPiPy.com, and Raspberry Jam developed by Alexander Pruss. In this tutorial we’re going to use…

What you’ll need Raspberry Pi (Ideally a Pi 2 or 3 if you want to use Chromium for streaming video) If installing from Raspbian from scratch, an 8GB Micro SD card Access to a computer for connecting via SSH and/or to install Raspbian Jessie with Pixel Pixel (Pi Improved Xwindows Environment, Lightweight), is the latest iteration of the Raspbian desktop. The major changes are apparent the first time you boot up – the multitude of boot messages has been replaced with a simple splash screen with the release number. There are now 16 stunning desktop background images to choose from thanks to Pi Foundation developer Greg Annandale. The icons on the file manager, task bar and menu now have a crisp, professional appearance. Menus are also cleaner and more readable…

The Raspberry Pi is elegant in its simplicity. This may explain why in a blog post in 2013 the Raspberry Pi Foundation revealed that only 0.02 percent of Pis are returned as defective. Of these around half were actually experiencing an issue that could easily be solved – so easily in fact that 10 year old Jessica, the daughter of Director of Software Engineering Gordon Hollingworth, was able to separate the good Pi units from the genuinely faulty ones. This being the case, if you are experiencing issues with your Pi, please don’t throw it away in frustration or send it back with an irate letter. It’s very likely that your issue can be solved (if not by a 10-year-old, then using a remedy found by one of the other…

What you’ll need ? This tutorial is compatible with all models of Pi running Raspbian Jessie With the advent of the dazzling Pixel desktop on the Pi, with its glitzy icons and crisp windows, some readers may be considering using a Pi as their home computer. This however is not especially secure given that the Pi automatically logs in the default user without requiring a password. Even if the password is required, anyone can mount the SD card to view your documents, pictures, videos and other data. 01 Back up your data If you have not done so already, log onto your Pi and transfer the contents of your Desktop, Documents, Pictures etc onto an external medium like a USB stick. This will make transferring your data to your encrypted…

The Raspberry Pi is probably best known as a platform for programming and physical computing projects, but it’s also a fullyfunctional computer, and like desktop computers and modern mobile devices of all kinds, it has a wide range of apps available to expand its capabilities. What you install will of course depend on what you want to do with your Pi, but this is our pick of 20 apps that we love, and that all work on the Pi with a default Raspbian install. While the Raspberry Pi no longer has an online “App Store” – the Pi Store ceased operating in early 2015 – some handy programs come pre-installed and many more can be installed without much trouble. Click Applications > Preferences > Add/ Remove Software to launch Raspbian’s…

01 Use a logic simulator Before looking at some examples of logic circuitry, here’s a tip to help you check your ideas out without wiring anything up at all. If you’re not quite sure which logic devices you need, this will allow you to be sure before placing an order for components. The secret is to use a logic simulator and there are lots to choose from, some that run locally under various operating systems and some that run online. Here we’re testing the circuit from Step 6 at logic.ly/demo. 02 Use a 2-to-4 decoder Driving four LEDs usually requires four GPIO pins. However, if we have an application where only one of them needs to be illuminated at any one time, as might be the case if the LEDs…

What you’ll need Wi-Fi enabled Raspberry Pi Parrot Drone 2.0 (or other) Drones are becoming ever more popular and mainstream. You may already be aware that Amazon is currently working on using drones to deliver packages directly to your house within hours of you placing an order, creating a new requirement for them to be autonomous and programmable. This tutorial offers a little taster of a Python module which enables you to write and deploy programs to your drone. The API used is now a few years old (2014) and supports operation with Python 2.7. However, it offers a number of simple methods for beginners to create their own programs and spark your curiosity. The tutorial begins with a quick walkthrough on installing the required software and libraries. Then jump…

What you’ll need ■ Suitable for all models of Raspberry Pi If you’re worried about the somewhat Orwellian notion of forced disclosure of passwords, this project posits a rather radical solution to the dilemma by creating a second password for your user account, which, instead of logging you in, will nuke your home folder using special tools. While this is simple to set up, do make sure to back up your personal data to a safe place before going ahead. Also bear in mind that anyone with physical access to your machine may seize it before you have a chance to flip this kill switch. 01 Create your new user account Although you most likely will already have a user account on the Pi, create a new one for this…

The Raspberry Pi has transformed the way we look at computers and computing. Thanks to its ridiculously low cost of ownership, you can build a fully functional computer for under a tenner and put it to all kinds of uses. Sometimes that potential can be so open as to seem overwhelming – this is a computer that has gone into space, for goodness sake – but that shouldn’t stop you finding new and exciting ways to use it. The Pi’s versatility makes it the perfect tool for just about any task you could think for it to do. Looking for a desktop computer to replace your PC? The Raspberry Pi 3 has just about enough oomph – with the right support – to do that. How about using it as…

You’ve purchased your kit and you’re ready to build your ultimate desktop system. First things first: which distro will you choose? The obvious one is the default Raspberry Pi operating system Raspbian, but if you’re put off by its rather basic interface, then Ubuntu Mate should appeal. It provides a slicker, more desktop-like environment, but isn’t as well supported and there’s a performance price to pay for those bells and whistles – a slight tradeoff between desktop-like appearance and desktop-like performance – although you’re less likely to feel the pain with the Pi 3. If Ubuntu Mate sounds like it could be your kind of thing, check out the Run Ubuntu from USB box over the page. Boot into Raspbian from USB Instructions for preparing a Pi 3 for booting…

Resources McPiFoMo http://rogerthat.co.uk/McPiFoMo.rar Block IDs: http://bit.ly/ MC-BlockIDs Angry IP Scanner http://angryip.org/ download/ We will create a Python script that connects directly to a Minecraft game running on another Raspberry Pi, which will enable us to have some fun with their game world. We’ll have the ability to manipulate the character, the environment, and place blocks, as we’ve done in the previous tutorials, but this time we’re working on someone else’s game. We’ll be able to have pranks galore, but it should be mentioned that this should not be done without prior permission of the third party. This tutorial is written under the assumption that you’re running Minecraft Pi Edition on a Raspberry Pi. No additional software is required. If you’d like to run this tutorial on your own flavour of…

What you’ll need Minecraft www.mojang.com/games Python www.python.org McPiFoMo http://rogerthat.co.uk/McPiFoMo.rar Minecraft Turtle http://bit.ly/MinecraftTurtle Minecraft’s ‘Creative Mode’ is indeed a great mode to get creative with, but it’s a time-consuming job placing blocks down into your world one-by-one. That’s why we put together a package which incorporates a range of modifications that enable us to execute Python scripts directly into a Minecraft world. McPiFoMo includes MCPiPy by ‘fleap’ and ‘bluepillRabbit’ of https://mcpipy.wordpress.com, and the Raspberry Jam Mod, developed by Alexander Pruss. We’ll also be using Minecraft Turtle, which was put together by Martin O’Hanlon of http://stuffaboutcode.com. That’s a lot of mods, but together they allow us to do with Minecraft on Linux what would usually have only been possible with the Raspberry Pi edition of Minecraft. As a prerequisite, we strongly recommend…

What you’ll need Raspberry Pi Four jumper jerky wires (female to female) Design Spark tilt switch GPIO pin numbering GPIO pins are a physical interface between the Pi and the outside world. At the simplest level, you can think of them as switches that you can turn on or off. You can also program your Raspberry Pi to turn them on or off (output). The GPIO. BCM option means that you are referring to the pins by the Broadcom SOC channel number. If you start counting the pins this is the physical pin number. The GPIO.BOARD option specifies that you are referring to the pins by the plug number, i.e. the numbers printed on the board. A tilt switch is a component capable of sensing a change in orientation in…

Resources Raspberry Pi Pimoroni Speaker pHAT http://bit.ly/Speaker-pHAT Hammer headers (optional) http://bit.ly/HammerHeaders The Raspberry Pi Zero is awesome. However, it lacks an ‘on the go’ audio solution. Worry no longer, as Pimoroni has created an ’80s-style boombox speaker known as the Speaker pHAT. It crams an I2S DAC and mono amplifier, a tiny 8 2W speaker and a 10 LED bar graph onto one teeny little pHAT. A simple solution to add audio to your Pi, it is compatible with all models. Now you can integrate music, notifications, speech and sound into all your projects. It comes as a complete kit, and this tutorial walks you through how to set up and prepare the hardware; the installation of the software; how to alter and adjust the volume setting; and finally, for…

Like it? If you want to see how the ZeroBot’s hull and wheels were designed, you can download the 3D files from Fusion 360 (http://a360.co/2rV2NQo). For the STL files you’ll need to go to Thingiverse (http://bit.ly/Zerobot). Further reading Max undertook an extended internship, which sparked an interest in CAD design and you can see that on show at his blog. Head to http://coretechrobotics.blogspot.co.uk to see his cute Attiny Canbot and quadruped robot. For his latest botrelated exploits, follow him on https://hackaday. io/Max.K. What’s so great about reading about this project is how you often mention code you’re revisiting from previous projects and how each one builds on your past work and experiences. How long have you been into maker projects, particularly robots? I only really started to tinker with electronics…

There’s a wide range of programming languages that can be used with the Raspberry Pi, but Scratch is great for beginners, because it introduces many of the concepts of programming while being easy to use. It’s especially good for creating graphical programs such as games. You’ll find Scratch on the desktop in Raspbian, so there’s no need to install anything – just click on the icon to get started. (Many other operating systems for the Pi don’t support Scratch, although you can download Scratch for Windows, Mac or Linux at https://scratch.mit.edu. Our tutorials will be equally applicable whatever your platform.) The main window in Scratch is split into three sections: the bits you can use to make programs are on the left; you piece them together in the middle; and…

The popularity of Scratch has soared since the Raspberry Pi was released. Children across the United Kingdom have started their coding journey using this effective tool. Why is it so popular? Scratch beautifully demonstrates the basics of Computer Science, loops, iteration, variables, arrays etc. But Scratch manages to keep all of these concepts relatively simple and easy for the user, typically a child, to use. When children first use Scratch, they simply treat it as a set of building blocks, connecting blocks together and seeing what they can create. But over time and with the help of the curriculum in our schools, children are learning key skills which can be applied to all languages, all thanks to Scratch. The Raspbian operating system, the de facto standard for all versions of…