Tabla de contenidos para Raspberry Pi Tips, Tricks & Hacks Volume 2 en Raspberry Pi Tips, Tricks & Hacks

Imagine, if back in 1999, someone came up to you and told you that in 15 years, you’d be able to carry a customisable computer that could play games, control robots, check the temperature in real time, and be used as a remote control in your pocket. Imagine they said that in 16 years, you could buy this computer for under a tenner. You would call them mad, wouldn’t you? Well, that madness has become a reality, ever since the Raspberry Pi took the tech world by storm in 2012. Whether you’re a skilled programmer or a hobbyist, or even a cosplayer hoping to add an electronic wearable to your costume, there is a Pi project for everyone, regardless of skill level or budget. In this new volume of Raspberry…

For a lot of scientific problems, you need to play with your data in an interactive way. The original way you would do this was to use the IPython web notebook. This project has since been renamed Jupyter. For those who have used a program like Mathematica or Maple, the interface should seem very familiar. Jupyter starts a server process, by default on port 8888, and then will open a web browser where you can open a worksheet. Like most other programs of this type, the entries run in chronological order, not in the order that they happen on the worksheet. This can be a bit confusing at first, but it means that if you go to edit an earlier entry, all of the following entries need to be reexecuted…

What you’ll need ■ Raspberry Pi official 7-inch display ■ Power supply ■ Small Phillips screwdriver The Raspberry Pi Foundation has had plans for an official display since the very beginning – even the first Model B board that was released back in February 2012 had the necessary DSI connector. Development of the display module began in 2013, but as director of engineering Gordon Hollingworth explains in his recent blog post (bit.ly/1Z75He0) there were a number of issues along the way, including EMC (electromagnetic compatibility) testing and the sourcing of a high quality yet affordable display (which, from first-hand experience, are not easy hurdles to jump). However, the output device is exactly what you would expect from the Raspberry Pi Foundation: a beautiful 7-inch multi-touch capacitive screen for the incredible…

What you’ll need ■ Wireshark (www.wireshark.org) ■ PiCam module or USB webcam While you’re settling down to enjoy your latest boxset, there’s always that nagging feeling at the back of your mind – is the baby asleep, or crying down the house? Surround sound tends to get in the way, which means we need to rely on baby monitors. While audio monitors are useful, the trend these days is more towards video baby monitors, in particular those that display footage on an app or by opening an IP address in a mobile browser. Throw in some motion detection and alert software, and you’ve got an incredibly useful tool – which, you won’t be surprised to learn, the Raspberry Pi can do for a fraction of the cost. All you’ll need…

What you’ll need ■ Raspberry Pi ■ Sense HAT Last November, two Raspberry Pi computers were each fitted with an Astro Pi, which is an add-on board boasting an array of sensors and an 8x8 LED matrix. These were flown to the ISS and delivered to Major Tim Peake with a selection of school children’s experiments. In late December, the Astro Pi was released for sale to the public as the rebranded ‘Sense HAT’. This consists of exactly the same hardware and sensors set found on the Astro Pi but with a new ‘Sense HAT’ API. The first part of this two-part tutorial introduces you to the Sense HAT hardware and walks you through the skills required to create a Sense HAT version of the updated classic Rock, Paper, Scissors,…

What you’ll need ■ Raspberry Pi 2 ■ USB sound card (we used a Behringer UCA202) Full code FileSilo.co.uk /bks-967 We are going to take you through the basics of wavetable synthesis theory and use that knowledge to create a realtime synthesiser in Python. At the moment, it is controlled by the computer keyboard, but it could easily be adapted to accept a MIDI keyboard as input. The Python implementation of such a synthesiser turns out to be too slow for polyphonic sound (ie playing multiple notes at the same time) so we’ll use Cython, which compiles Python to C so that you can then compile it to native machine code to improve the performance. The end result is polyphony of three notes, so this is not intended for use…

What you’ll need ■ Article’s Github repository (http://github.com/alexellis/rpi-display) ■ Two Raspberry Pis ■ Pimoroni scrollphat (optional) ■ Soldering iron and solder We are going to create a networked sensor display with the Pimoroni scrollphat. We’ll take a look at the hardware, what’s included and how to install the required Python libraries. Then we will tour the library’s source code and code some examples that have been contributed by the open-source community through GitHub. Once we are familiar with the library, we will go on to set up our chosen sensor on the first Raspberry Pi and connect the screen to our Pi Zero. We’ll learn about how to use Redis (an open-source pub-sub noSQL database). Redis is our connective tissue, publishing events that our Zero will subscribe to and then…

What you’ll need ■ Pi-Mote IR control board with RC sockets bit.ly/1MdpFOU ■ Desk lamp ■ Accessories Full code FileSilo.co.uk /bks-967 The folks at Energenie have created some genius plug sockets that can be turned on and off via your Raspberry Pi. You can buy a starter kit which includes the RF transmitter add-on board and two sockets to get you started. The add-on board connects directly to the GPIO pins and is controlled with a Python library. Once everything is installed and set up, your Raspberry Pi can be used with the Pi-mote to control up to four Energenie sockets using a simple program. This tutorial covers how to set up the software, the sockets and how to adapt the program to run on your mobile device. 01 Set…

What you’ll need ■ Ethernet cable ■ Wireless router ■ USB WiFiadaptor or Raspberry Pi 3 Are you concerned about your online privacy? Suspect that the NSA or GCHQ are tracking you online? Or are you simply anxious about advertising networks targeting their ads at you? If this is the case, or you’re simply on the lookout for a new project, then setting your Raspberry Pi up as an anonymising Tor wireless access point is a good way to save time and effort setting up Tor on all of your PCs and mobile devices. If you’re unaware, Tor is free software that enables anonymity online and routes internet traffic through a worldwide anonymising network of over 7000 relays. By doing this, your location and website use can be concealed from…

In its short life so far of just over three years, the Raspberry Pi has been an absolute game changer – not just as a piece of reduced price hardware, but for nurturing a community of like-minded individuals with a common goal: learning and making awesome stuff! We can’t recall the number of times we’ve browsed over to the Raspberry Pi blog and been blown away by the brilliance of a new project. From sorting Portuguese mail to making bullet time rigs, there are a lot of incredible projects out there – more and more are surfacing every day. People often ask what they can do with a Raspberry Pi and it is actually sometimes difficult to articulate an answer to that question, as the use cases are so broad…

The Raspberry Pi Zero is tiny, ridiculously tiny. It’s a wonderful, impressive piece of tech, but we can’t help wondering – because we’re terribly serious adults, honestly – where can we stuff the Zero for maximum fun? It’s small enough to be hidden in a variety of household objects in order to enhance their capabilities. Whatever you can find to fit it in, you can turn into some kind of smart machine. Okay, wiring it in to your vacuum cleaner in the hope of making an ersatz Roomba is probably a little tricky – but there are all sorts of electronic gadgets lying around your home which can be brought back to life with a little bit of effort. Take old game controllers. If you’re anything like us you’ve probably…

3D-print this case! FileSilo.co.uk /bks-967 What you’ll need ■ Raspberry Pi 2 ■ Latest Raspbian image raspberrypi.org/downloads ■ Minecraft Pi Edition pi.minecraft.net ■ Raspberry Pi case ■ USB game controller (PS3 preferable) Minecraft means m any things to m any p eople, and to Raspberry Pi users it’s supposed to mean education. N ot e veryone k nows, t hough, t hat you can still have fun and play Minecraft as you normally would. Using Raspberry Pi, it is also the cheapest way to get a fully-functional version of Minecraft up onto your TV. However, in its normal state, just being on a TV isn’t the end of it. Using all the features and functions of the Pi, we can take it to a state more fitting of a TV…

What you’ll need ■ Raspbian Wheezy ■ HDMI cable ■ Monitor/TV display Finding the content you’re interested in viewing can take a while. W hether y ou’re l ooking f or i nternet T V s tations, video podcasts, audio podcasts or shows syndicated online, taking the time to find and download them can be slow going, particularly if you have a busy lifestyle. You might even have no time to watch after you’ve waited for the download. Thanks to the Miro media management software, we can automate all of this, and with the software running on a Raspberry Pi, you can easily build a compact system for downloading and playing back shows that you have an interest in. We’re talking targeted TV on demand, which makes this project ideal…

Putting circuits together can be tricky, even for experts. Fortunately, various notations exist that make it easier to work out just where wires, components and power sources are connected. But rather than jot these details down with a pencil and paper, you might prefer to bring an element of realism to the illustration. This is particularly useful for beginners, and if you’re demonstrating a breadboard-mounted circuit with an Arduino, for instance, you might wish to clearly and accurately illustrate the precise positions of each component and wire. This is where Fritzing comes in. You’ve probably seen illustrations of circuits in the pages of Linux User & Developer over the years, and with Fritzing you too can put together circuit illustrations, simply by dragging and dropping the categorised components into place,…

What you’ll need ■ Pi-Mote IR control board bit.ly/1MdpFOU ■ Remote controlled robot You can use a Raspberry Pi and an Energenie IR board to make a brilliant remote and control your TV, but you can do so much more. Welcome to the world of the IR board, where almost anything is possible. We’ll use it to record signals from a remote control robotic toy and combine these with pygame commands to enable you to control your robot from your Raspberry Pi. Since the code is Pythonbased, you can then develop it further, use social media to control the robot with tweets, or install Flask to create a web interface accessible from your mobile phone. 01 Update the boot file Before booting up your Raspberry Pi, attach the Energenie IR…

Welcome to our latest FUZE BASIC tutorial. If you haven’t already gotten hold of this programming language, FUZE BASIC can be downloaded for free for both Linux and Raspberry Pi users from fuze.co.uk/getfuzebasic. So why should you bother to learn BASIC? Well, BASIC (Beginner’s All-purpose Symbolic Instruction Code) was instrumental in starting the computing revolution back in the Seventies and Eighties. Thirty years on and BASIC, or in this case FUZE BASIC, presents a modernised version of the original classic. Now with updated commands for advanced sprite and media handling, the removal of goto and gosub commands as well as line numbers, and the fact that on modern hardware it races along, it still remains one of the easiest introductions for users wanting to jump into the world of programming.…

Full code FileSilo.co.uk/bks-967 Welcome to the final episode of our FUZE BASIC tutorial. Over the last two issues we’ve built up a retro tunnel shooter game inspired by the classic Tempest. This month, we’re going to add in the last few features and tighten up our code to make this into a fully functional game. At almost 900 lines, 73MP357 is now a fairly significant program. You will need to download the full program as well as a few sound effect and music files, all of which are available to download from this issue’s FileSilo page or from fuze.co.uk/tutorials/73MP357.zip. Download and decompress the files, then save the resulting folder to your FUZE BASIC folder. This final version is exactly that: the finished article. We now have levels, enemies, explosions, music…

What you’ll need ■ USB Bluetooth Low-Energy device bit.ly/1MtDbJC ■ Android/iOS device ■ Android/iOS beacon app ■ BlueZ The 2002 movie Minority Report, based on the Philip K Dick novel, is set in the archetypal dystopian future, where police react to crimes before they happen and adverts are targeted at individuals. Such targeted advertising displayed ads and messages based on your identity, interests and habits. It was seen as one of many futuristic elements to the film, but fast-forward to 2015, and that targeted advertising is here. While it doesn’t rely on retinal identification (yet), iBeacon from Apple uses Bluetooth and an iPhone 4S or later in close proximity to trigger an app or message. Google, meanwhile, has its own version, known as Eddystone. Raspberry Pi owners can investigate this…

Mostly, our tutorials are about completing a specific project and reaching a particular goal. However, this time we’re doing something a bit different. We are showing you some Android apps that you can use along with your Ras Pi. These apps aren’t tied to particular projects – you can use them whenever and as often as you like – but we think they can add something to your whole experience with the Pi. Some of the apps in our list are Pi-specific, while others are more general but have a Pi relevance. Chances are you might already know or use one or two, but we hope that you can discover something new from the selection on offer. If you have an Android phone or tablet and have not explored the…

What you’ll need ■ Sensly HAT sensly.uk The Sensly is a smart module attached to the Raspberry Pi. It has its own microprocessor that can handle analog data and handle sampling from various sensors without the need to waste your Raspberry Pi’s processing power. There are three different gas sensors attached to the board, allowing you to sense a multitude of gases, as well as humidity and temperature sensors. Plus, this Raspberry Pi HAT can be easily extended with its array of analog ports and an I2C interface. In keeping with the Raspberry Pi way of doing things, the module also provides a Python API that does all of the hard work for you. All of the maths, calibration and error correction is handled by the API itself, allowing you…

What is an emulator? An emulator is software which lets your computer pretend to be a different sort of computer. It will allow a Raspberry Pi Zero to run software originally designed for the Sega Mega Drive, or Nintendo N64, old DOS-based PCs, etc. Emulators aren’t without their problems, though – it’s nearly impossible to perfectly recreate a games console in software. Keep in mind that older games may have bugs ranging from minor sound and graphical glitches to full-blown crashes. Right, you’ve got your Pi safely ensconced in a controller – all you need now are some videogames to play! We’re going to be using the RetroPie emulator. By the end of this tutorial, you’ll be able to play games directly from your Raspberry Pi, provided that you legally…

You may remember or have even played the classic Minesweeper P C g ame t hat o riginally d ates b ack t o t he 60s. Over the years it has been bundled with most operating systems, appeared on mobile phones, and even featured as a mini-game variation on Super Mario Bros. This project will walk you through how to create a simple version in Minecraft: it’s Minecraft Minesweeper! You will code a program that sets out an arena of blocks and turns one of these blocks into a mine. To play the game, guide your player around the board. Each time you stand on a block you turn it to gold and collect points, but watch out for the mine as it will end the game and cover…

What you’ll need ■ Raspberry Pi B+ ■ Tilt, roll, pressure and temperature sensors ■ 3D-printed camera tilt and propellers ■ Camera module ■ USB joystick control ■ Ethernet cable Why did you decide to build an ROV (remotely operated vehicle)? When I was a kid I frequently built RC models; sailing boats and speedboats. While I owned a fantastic RC glider and dreamed of having my own RC submarine someday, my neighbour at the time had an RC submarine and discouraged me from building one by saying this thing always had trouble with its electronics and leakage. Besides, almost all waters are murky in our area! Around the end of 2014, I saw a National Geographic e pisode a bout t he s alvage of the Costa Concordia and…

What you’ll need ■ Raspberry Pi 2 ■ Raspbian r aspberrypi.org/downloads ■ Keyboard ■ Mouse ■ Wireless dongle ■ Monitor ■ Case ■ Powered USB hub (optional) The Raspberry Pi 2’s increased power over its predecessor is well-documented by now. More CPU cores and more RAM making it six times faster is an impressive number, and you can see the actual changes that it makes to the experience. This power actually enables you to conduct a very simple project that was just out of reach for the original Raspberry Pi: a Raspberry Pi desktop PC. All the components for it were available, but the Pi was just a little too slow to properly give a fluid desktop experience. Now with the improved resources, many of the restrictions are gone –…

What you’ll need ■ Github repository github.com/alexellis/docker-arm ■ Arch Linux for ARM archlinuxarm.org Docker is a framework and toolchain used to configure, build and deploy containers on Linux. Containers provide a means to package up an application and all its dependencies into a single unit. This makes them easy to share and ship anywhere, giving a lightweight and repeatable environment. Each application runs in its own isolated space sharing the host’s kernel and resources, in contrast to a virtual machine which needs to ship with a full operating system. A Docker container can be started or stopped within a second, and can scale to large numbers while having minimum overhead on the host’s resources. The Docker community has built out a clustering solution called Swarm which, as of version 1.0,…

Full code FileSilo.co.uk/bks-967 Welcome to part two of our FUZE BASIC tutorial. Y ou w ill n eed t o F UZE B ASIC installed for this, and it can be downloaded for free for Linux and Raspberry Pi users from www.fuze.co.uk/getfuzebasic. Don’t worry; it’s possible to skip part one and just jump straight in here. However, because this is a fairly large program, you won’t be typing in off the page. Instead you will need to download the program listing from FileSilo or here: www.fuze.co.uk/tutorials/73MP357PART2.fuze. 73MP357 is coded by Luke Mulcahy, FUZE’s resident coder and, in the nicest way possible, our very own human supercomputer. This issue he tasks his brain with developing the basic game structure further, adding all sorts of awesome trinkets to delight. These include simple…

What you’ll need ■ NoIR camera module ■ LISIPAROI LED light ring bit.ly/1meQGaR ■ PIR Sensor ■ Portable battery You are probably already familiar with the Raspberry Pi camera module. However, it is also available in the NoIR edition – ‘NoIR’ in this instance being shorthand for ‘no infrared’. Using this module, you can use the camera to take photos and video footage in the dark, similar to a night vision camera. Many of us are fortunate enough to have a wide variety of animals that visits our gardens and homes, and while we obviously see them more during the day, there are also a large number of nocturnal visitors to your garden. This tutorial shows you how to set up your camera, then add and combine an infrared light…