Indholdsfortegnelse for Issue #03 i MakerSpace

The Gemini Protocol [1] is a relatively new Internet communication protocol for accessing remote documents. Unlike an HTML web page that contain layers of style sheets, JavaScript, and HTML tags, a Gemini document is a simple readable document. Gemini’s Gemtext format is easy to learn, requiring about five codes. Children or new coders could easily put together a small documentation server or custom application server without many programming skills. In this article, I introduce the Gemini protocol with three simple projects. The first project creates a Gemini server and client with just one line of Bash code. In the second project, a Bash script creates a common gateway interface (CGI) page that connects to a sensor to show temperature and humidity data. The third project uses Gemini document links to…

Whether in an apartment, on a balcony, in a greenhouse, or in a garden, if you are not at home and want to water your plants remotely, an automated system is your only option. In this article, I show you how to harness the power of a Raspberry Pi Zero as a reliable helper to manage the watering system. Design Automatic irrigation is nothing new. These systems not only exist on a large scale in agriculture and horticulture but have also been available for many years for domestic use. Some providers attach their systems directly to the water supply. In this project, I’ll instead draw water from a 200-liter tank reservoir with a supply that will last for a couple of dry days (Figure 1). The advantage of a tank…

For Raspberry Pi users, Xonsh [1] offers many opportunities to write some extremely lightweight scripts, with Python connecting to physical devices and Bash utilities accessing system and file resources. In this article, we look at two lean Xonsh projects for the Raspberry Pi. The first program connects to a DHT11 temperature and humidity sensor and shows the results in a Bash dialog in just five lines. The second project calls the Bash top utility in a lean eight lines to show the Raspberry Pi idle time and user time on a 16x2 LCD screen. Getting Started Xonsh has two requirements: Python 3.8 or greater and a Bash shell. To install and run Xonsh on a Raspberry Pi, Ubuntu, or Debian system, enter: When the Xonsh shell opens, the terminal label…

The Nibble kit by CircuitMess [1] comes with everything you need to build a portable game console. It even includes a soldering iron to solder the buttons. The lead-free solder included in the kit will easily last for several more projects. The kit also includes a simple screwdriver for assembling the case, and you won’t hear this very often: The batteries are included (Figure 1). The kit is suitable for children from nine years up, but as my test shows, older users can have fun with the kit, as well. The very detailed and easy-to-understand instructions explain all the build actions step by step. In some places, links to online videos lend further help. The assembly instructions are available for download on the manufacturer’s site in several languages [2]. The…

If you use your Raspberry Pi to control sensors or displays, you will frequently have to deal with wiring problems or resort to using a soldering iron. Plug-and-play systems such as Adafruit STEMMA-QT [1], Seeed Grove [2], SparkFun Qwiic [3], and DFRobot Gravity [4] provide connection systems for electronic components. A system recently introduced by Tinkerforge [5] can also be plugged together, but it plays in a different league, because it comes with an additional microcontroller for management tasks on each module. The systems I will discuss in this article offer special cable connections on the devices (Figure 1). Common to all systems are reverse-polarity-proof connectors and symmetrical cables. In other words, the cable has connectors that look identical on both sides, but they are not the same internally and…

What is causing the smart home hype? Do you really need socket outlets that can be switched on by your cell phone, and if so, what is it all good for at the end of the day? Starting a Raspberry Pi project to find the answer to such questions has always proved to be a workable approach, thus far. Even if my answer to the “Do I need it?” question was, “No,” one thing is for sure, open source and Raspberry Pi can do it. Of course, a targeted solution needs to meet a number of criteria. It should be based on standards for which sufficient numbers of different components exist, while being open source. All components need to harmonize with the Raspberry Pi, work as self-sufficient systems without any…

When we think of operating systems (OSs) today, we assume that we’re running lots of concurrent processes on a machine, and the OS is responsible for fairly distributing resources (e.g., processor time and memory) to those processes. We may also think about the collection of hardware drivers that comes with the OS and lets us run software that prints on ink jet and laser printers, connects to the Internet via network adapters, and embeds videos from an internal or external webcam – all without containing any specific code for all those peripherals. Applications just assume that some generic device is available, and they ask the OS to send page layout data to a printer, data packets to a server, or fetch an image from the camera. The OS then must…

Assembler programs run directly on the computer’s hardware, which means they can reach nearly the maximum achievable speed of execution. Because assembler program code is very low level, writing the code is more complicated, but it is still the best choice for some tasks, especially on a computer such as the Raspberry Pi with its limited resources. Before you can start creating programs, however, you need to plumb the depths of the CPU and peripheral architecture. Machine Code To begin, it makes sense to clarify some terms. The CPU only understands machine code – zeros and ones or, more precisely, voltage levels that represent zeros and ones. Each command in machine code has a human-readable abbreviation that is easy to remember. These abbreviations are known as mnemonics and act as…

Alarge number of pins, variable voltage input, and good community support are what make the Raspberry Pi Pico a popular single-board computer (SBC) for newcomers and professionals alike. Just connect it to your PC over USB and get started, power supply included. When you want the Pico to run autonomously, you will need to face the question of how long the battery supply will last. Like most microcontrollers, the Pi Pico requires comparatively little power, but it has limitations when it comes to operating continuously on battery operation, not least because it continues to consume power during sleep periods. A few tricks will help you reduce the power consumption in these phases to extend the battery runtime. Whenever you read “Pico,” it also applies to other microcontrollers, either because they…

Radio-frequency identification (RFID) tags have become indispensable in industry and government, as well as the wholesale and retail spaces. The inexpensive transponder chips can be found on clothing labels, identification cards, and credit cards. Armed with just a Raspberry Pi and an RFID kit, you can read the data from these chips and view it on a display. In this project, I read serial numbers from RFID tags stuck on 3D-printed pumpkins – a slightly different kind of detection task. To do this, I connect an RC522 [1] RFID kit and a 1.8-inch ST7735 serial peripheral interface (SPI) thin-film transistor (TFT) display [2] to a Raspberry Pi 4. Together, the two modules can cost less than $15 (EUR15, £14) in online stores. The pumpkins contain simple RFID tags [3], also…

Amuseum exhibit called Buzzwire looks like outlines of two oversized hands giving you a high five (Figure 1). Each hand has a metal handle with a loop, and your goal is to move the loops up and down the hand without touching it. For an even bigger challenge, you can try to do both hands at once in the same or opposite directions. If either loop touches the hands, a buzzer and light come on and the handle vibrates. The original circuitry for the hands comprised interconnecting timer relays to switch the assorted components. The design had no microcontrollers or anything smarter than a switch, which had several drawbacks – but the main one was that if the puzzle was abandoned mid-run, the light, buzzer, and vibration motor would run…

Aquarium feeders have been around for a long time, but after my recent research, none of the devices really seemed practical to my mind. Very few devices provide feedback about malfunctions, which could be a nasty surprise when you return home. I created this automatic feeder project for my aquarium for peace of mind. A Raspberry Pi Zero is a good choice as a control center for a fish feeder: It comes with everything you need to control the mechanical system and to grab images with a Pi cam (Figure 1). It is also compact enough to fit in a small housing. Integrating a Pi Zero W with your wireless home network will allow you to post various captured images online while you are on the road. The goal was…

If you like old arcade machines, you will be familiar with the MAME project [1]. Originally, MAME stood for Multiple Arcade Machine Emulator, but today it does much more. MAME is a collection of software emulators for classic arcade machines, home computers, and game consoles. To play games on MAME, you will need to download individual game files or a 60GB collection from the Internet Archive [2]. Then you can launch games from a GUI that lets you search by name, publication year, and other criteria (Figure 1). You will find more than 30,000 titles that run on MAME by searching the Arcade Database [3]. While MAME has attracted many users and developers thanks to its availability on Windows, Linux, macOS, and other systems, some classic gamers notice subtle differences…

Beginner’s All-purpose Symbolic Instruction Code (BASIC), a classic computer language, dates back to 1964. Originally intended for beginners, BASIC was easier to use than the cryptic Fortran, which was popular for solving science and engineering problems. BASIC became extremely successful in the 1980s when every kid who owned a home computer (e.g., the Commodore 64 or the ZX Spectrum) was greeted with a BASIC prompt whenever they turned on their machine. Still popular today, you’ll find BASIC used as a macro language in many office suites, among other uses. Two popular BASIC dialects were developed by Microsoft and the British Broadcasting Corporation (BBC). After some background information on BASIC, I’ll take a closer look at BBC BASIC, the BBC version. BASIC Fundamentals All the early versions of BASIC used line…

For as long as the Raspberry Pi has been around, wiringPi has served as a library for accessing the GPIO. With the related gpio tool, programmers could quickly manage the GPIO at the command line. Many Raspberry Pi projects build on this library. Not least because of frustration about what were in part rude email communications from some users, developer Gordon Henderson decided to discontinue his one-man wiringPi project in August 2019 after releasing his last version. He explained in great detail on his website why he had stopped developing the library. The post, which has since been deleted, is still available on the Wayback Machine internet archive [1]. For more information, see the box “The Two Sides of Open Source.” If you want to continue using the Raspberry Pi’s…

MakerSpace is looking for fresh, original articles on Raspberry Pi and other maker hardware platforms. If you work with Raspberry Pi, Arduino, BeagleBone, MinnowBoard, Parallella, or another similar technology, and you have an interesting story about a recent project or configuration, drop us a line at edit@makerspace-magazine.com. We’re also seeking articles on software tools for maker hardware environments – including applications in the repositories of the leading Raspberry Pi operating systems, as well as homegrown scripts for custom configurations. We’re especially interested in electronics projects that use Raspberry Pi’s GPIO to control realworld hardware devices for a practical (or whimsical) purpose. Write for MakerSpace and share your story. Authors Bernhard Bablok 8, 40, 94 Erik Bärwaldt 66 Hans-Georg Eßer 3. 58, 70, 76 Swen Hopfe 44, 48 Brooke Metcalfe 80…