Doug Lowe

Article / Updated 09-13-2023

Before you can fire up your Raspberry Pi and start building your own electronics projects, you need to do some basic setup work. Start by setting up the hardware. You'll need the following to set up your Pi so that you can program it for your projects: A Raspberry Pi 2 or 3. A suitable power supply: The Raspberry Pi requires a 5 V power supply connected via a micro-USB connection on the card. The Pi itself will draw about 800 mA, so be sure to use a power supply that can handle at least that much current draw. A monitor: You don't need a large monitor, but go for at least 17 inches. An HDMI cable: If your monitor has an HDMI connection, you'll need a cable with HDMI connectors on both ends. If your monitor has some other type of connection, such as DVI or VGA, you'll need an adapter to connect your monitor to the Pi's HDMI connector. A USB keyboard: Any keyboard with a USB connector will do. A USB mouse: Any mouse with a USB connector will do. A microSD card with NOOBS: The Raspberry Pi uses a microSD card instead of a disk drive. Ideally, you should purchase a microSD card that already has a special program called NOOBS installed on it. (NOOBS stands for New Out Of the Box Software.) This program will allow you to install an operating system so that your Pi can run. If you prefer, you can format your own microSD card for your Pi. You can do that by downloading NOOBS from Raspberry Pi — Teach, Learn, and Make with Raspberry Pi on your computer and then copying the NOOBS software to the microSD card. A network connection: A network connection is essential to download several of the support packages you'll need for your projects. You can connect your Pi to a network in one of two ways: If you have a Raspberry Pi 3, you can use the built-in Wi-Fi to connect to a wireless network. You can use a standard Ethernet cable to plug a Raspberry Pi 2 or 3 into a wired network, provided you have a nearby router or switch with an available network port. That's all you need to get started. Plug the monitor, mouse, and keyboard into your Pi's HDMI and USB ports, insert the microSD card into the microSD slot, and then plug in the power connector. Your Pi will start right up.

Article / Updated 09-11-2023

All of electronics can be divided into two broad categories: analog and digital. One of the most common examples of the difference between analog and digital devices is a clock. On the analog clock, the time is represented by hands that spin around a dial and point to a location on the dial that represents the approximate time. On a digital clock, a numeric display indicates the exact time. Analog refers to circuits in which quantities such as voltage or current vary at a continuous rate. When you turn the dial of a potentiometer, for example, you change the resistance by a continuously varying rate. The resistance of the potentiometer can be any value between the minimum and maximum allowed by the pot. If you create a voltage divider by placing a fixed resistor in series with a potentiometer, the voltage at the point between the fixed resistor and the potentiometer increases or decreases smoothly as you turn the knob on the potentiometer. In digital electronics, quantities are counted rather than measured. There’s an important distinction between counting and measuring. When you count something, you get an exact result. When you measure something, you get an approximate result. Consider a cake recipe that calls for 2 cups of flour, 1 cup of milk, and 2 eggs. To get 2 cups of flour, you scoop some flour into a 1-cup measuring cup, pour the flour into the bowl, and then do it again. To get a cup of milk, you pour milk into a liquid measuring cup until the top of the milk lines up with the 1-cup line printed on the measuring cup and then pour the milk into the mixing bowl. To get 2 eggs, you count out 2 eggs, crack them open, and add them to the mixing bowl. The measurements for flour and milk in this recipe are approximate. A teaspoon too much or too little won’t affect the outcome. But the eggs are precisely counted: exactly 2. Not 3, not 1, not 11/2, but 2. You can’t have a teaspoon too many or too few eggs. There will be exactly 2 eggs, because you count them. So which is more accurate — analog or digital? In one sense, digital circuits are more accurate because they count with complete precision. You can precisely count the number of jelly beans in a jar, for example. But if you weigh the jar by putting it on an analog scale, your reading may be a bit imprecise because you can’t always judge the exact position of the needle. Say that the needle on the scale is about halfway between 4 pounds and 5 pounds. Does the jar weigh 4.5 pounds or 4.6 pounds? You can’t tell for sure, so you settle for approximately 4.5 pounds. On the other hand, digital circuits are inherently limited in their precision because they must count in fixed units. Most digital thermometers, for example, have only one digit to the right of the decimal point. Thus, they can indicate a temperature of 98.6 or 98.7 but can’t indicate 98.65. Here are a few other thoughts to ponder concerning the differences between digital and analog systems: Saying that a system is digital isn’t the same as saying that it’s binary. Binary is a particular type of digital system in which the counting is all done with the binary number system. Nearly all digital systems are also binary systems, but the two words aren’t interchangeable. Many systems are a combination of binary and analog systems. In a system that combines binary and analog values, special circuitry is required to convert from analog to digital, or vice versa. An input voltage (analog) might be converted to a sequence of pulses, one for each volt; then the pulses can be counted to determine the voltage.

Article / Updated 08-31-2023

As an IT professional, cybersecurity is the thing most likely to keep you awake at night. You must consider two basic elements as part of your cybersecurity plan: Prevention: The first pillar of cybersecurity is technology that you can deploy to prevent bad actors from penetrating your network and stealing or damaging your data. This technology includes firewalls that block unwelcome access, antivirus programs that detect malicious software, patch management tools that keep your software up to date, and antispam programs that keep suspicious email from reaching your users’ inboxes. The most important part of the prevention pillar is the human firewall. Technology can only go so far in preventing successful cyber attacks. Most successful attacks are the result of users opening email attachments or clicking web links that they should have known were dangerous. Thus, in addition to providing technology to prevent attacks, you also need to make sure your users know how to spot and avoid suspicious email attachments and web links. Recovery: The second pillar of cybersecurity is necessary because the first pillar isn’t always successful. Successful cyber attacks are inevitable, so you need to have technology and plans in place to quickly recover from them when you do.

Article / Updated 08-31-2023

Security techniques and technology — physical security, user account security, server security, and locking down your servers — are child’s play compared with the most difficult job of network security: securing your network’s users. All the best-laid security plans are for naught if your users write down their passwords on sticky notes and post them on their computers and click every link that shows up in their email. The key to securing your network users is to empower your users to realize that they’re an important part of your company’s cybersecurity plan, and then show them what they can do to become an effective human firewall. This necessarily involves training, and of course IT training is usually the most dreaded type of training there is. So, do your best to make the training fun and engaging rather than dull and boring. If training isn’t your thing, search the web. You’ll find plenty of inexpensive options for online cybersecurity training, ranging from simple and short videos to full-length online courses. You’ll also need to establish a written cybersecurity policy and stick to it. Have a meeting with everyone to go over the security policy to make sure that everyone understands the rules. Also, make sure to have consequences when violations occur. Here are some suggestions for some basic security rules you can incorporate into your security policy: Never write down your password or give it to someone else. Accounts should not be shared. Never use someone else’s account to access a resource that you can’t access under your own account. If you need access to some network resource that isn’t available to you, you should formally request access under your own account. Likewise, never give your account information to a co-worker so that he or she can access a needed resource. Your co-worker should instead formally request access under his or her own account. Don’t install any software or hardware on your computer — especially wireless access devices or modems — without first obtaining permission. Don’t enable file and printer sharing on workstations without first getting permission. Never attempt to disable or bypass the network’s security features.

Step by Step / Updated 06-05-2023

In PowerPoint 2016, a hyperlink is simply a bit of text or a graphic image that you can click when viewing a slide to summon another slide, another presentation, or perhaps some other type of document, such as a Word document or an Excel spreadsheet. The hyperlink may also lead to a page on the web. Adding a hyperlink to a presentation is easy. Just follow these steps:

Article / Updated 04-17-2023

The Artistic Effects command in PowerPoint 2013 applies one of several special filters to your picture in an effort to make the picture look like it was created by an artist rather than photographed with a $60 digital camera. Depending on the nature of the original picture, the results may or may not be convincing; the only way to find out is to try. Here is a list of the artistic effects that are available on the Artistic Effects button: Marker Pencil Grayscale Pencil Sketch Line Drawing Chalk Sketch Paint Strokes Paint Brush Glow Diffused Blur Light Screen Watercolor Sponge Film Grain Mosaic Bubbles Glass Cement Texturizer Crisscross Etching Pastels Smooth Plastic Wrap Cutout Photocopy Glow Edges To apply one of these effects, simply double-click the picture, click the Artistic Effects button on the Picture Tools Format tab, and choose the effect you want from the gallery. To give you an idea of what these effects can accomplish, this figure shows how a photograph appears with the Pencil Sketch, Watercolor Sponge, and Plastic Wrap filters applied.

Article / Updated 03-01-2023

A Raspberry Pi (sometimes just called a Pi for short) is a very small computer. Raspberry Pi is a popular alternative to Arduino, BASIC Stamp, and other types of microcontrollers and is the ideal computer for people who love to make their own gadgets. Physically, a Raspberry Pi resembles an Arduino or a BASIC Stamp. However, the Raspberry Pi is much more than a microcontroller; it is a full-blown computer system, implemented on a single small card. In fact, a Raspberry Pi has most of the features commonly found on a desktop or laptop computer. Yet, besides its small size, a Raspberry Pi has other features not commonly found on a desktop, such as the ability to directly control digital I/O pins. Thus, you can use a Raspberry Pi with external devices such as LEDs, push buttons, potentiometers, various types of sensors, and servo or stepper motors. It contains most of the components found in a traditional desktop computer, but all squeezed onto a small board about the size of a deck of playing cards. The newest version of the Raspberry Pi, called the Raspberry Pi 3, is pictured here. This version of the Raspberry Pi includes all of the following packed onto the board: CPU: A quad-core 64-bit ARM Corex-A53 microprocessor running at 1.2GHz. RAM: 1GB. USB ports: Four standard-size USB 2.0 ports mounted on the board. These ports can be used to connect any USB device, including a keyboard, a mouse, or a flash drive. Video: A built-in graphics processor that can support 1080p resolution (1920 x 1080). HDMI: A full-size HDMI connector is mounted on the board to connect a video monitor. Display serial interface (DSI): A display interface designed to connect to small LCDs via a 15-pin ribbon cable. MicroSDHC card: The MicroSDHC card acts as the computer's disk drive. The operating system (Linux) is installed on the MicroSD card, along with any other software you want to use. Ethernet networking: A built-in RJ-45 connector for networking. 802.11n wireless network: A built-in wireless network connection. The antenna is actually built into the board itself, so no external antenna is needed. Bluetooth: Built-in Bluetooth networking for wireless devices such as a keyboard, a mouse, and headphones. Camera serial interface (CSI): A special interface designed to connect to a camera device via a 15-pin ribbon cable. Audio: A 3.5mm audio jack for sound applications. Power: The Raspberry Pi is powered by a 5 V supply connected to the board via a micro-USB connection, the same type used by most smartphone rechargers. GPIO header: The most interesting thing about the Raspberry Pi from an electronic enthusiast's perspective is the 40-pin GPIO header, which provides access to a variety of features, including 26 general-purpose input-output (GPIO) pins. These pins work the same as the digital I/O pins found on Arduino and BASIC Stamp microprocessors, and can be accessed via programs that you write for the Raspberry Pi. You can use these GPIO pins as output pins to connect to devices such as LEDs, servo or stepper motors, and so on. Or, you can use them as input pins to read input from external switches, potentiometers, or other types of sensors. Unlike the digital I/O pins found on Arduino or BASIC Stamp microprocessors, the Raspberry Pi GPIO pins work at a voltage level of 3.3 V rather than 5 V to indicate HIGH signals. You'll need to adjust your circuits accordingly to deal with the smaller input and output voltage levels. In particular, if you apply a 5 V input to GPIO input pin, you run the risk of damaging your Raspberry Pi.

Cheat Sheet / Updated 02-02-2023

As you design and build with electronic circuits, you’ll invariably find yourself scratching your head trying to remember what color stripes are on a 470 Ω resistor or what pin on a 555 timer integrated circuit (IC) is the trigger input. Never fear! This handy Cheat Sheet will help you remember such mundane details so you can get on with the fun stuff.

Cheat Sheet / Updated 01-11-2023

Writing Java statements (like for and if) and classes (like Math and NumberFormat) help you start and build strong programs. Variables hold different kinds of Java data types: numbers, characters, and true/false numbers. You designate Java operations that can be performed on operands, including arithmetic operators, relational operators (or binary) and logical operators (or Boolean).

Article / Updated 09-30-2022

As a network administrator, the Internet is your best friend for networking resources, solutions, news, and guidance. Here are some websites for you to visit often. To register domains: InterNIC Network Solutions register.com To check your TCP/IP configuration: DNSstuff To see if your email server has been blocklisted: DNSBL.info To stay current in the industry, try these standards organizations: Institute of Electrical and Electronics Engineers International Organization for Standardization Internet Engineering Task Force Internet Society