Specials 2015 - 2020

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Join master hacker, engineer, and tech hobbyist Ben Heck as he tackles new and fun interesting projects each week. Whether he's combining a PS3, Wii U, and Xbox into one mega video game system or building his own pinball machine, Ben shows you step by step how you can take on all kinds of electronic projects. Ben also shares useful tips and answers your questions about 3D printing, microcontrollers, circuitry, modeling, design, and much more. What should Ben build next? Let us know!

Ben gives an update on the results of the TI Plant Booster after three weeks. See how the plant is doing against a control plant, a plant using natural light, and a plant using the light compensator.

Ben Heck's Lunch Box Dev Kit is a portable, plug-and-play hardware development enclosure suitable for diagnosing problems on the go and swapping over between kits. It includes a screen, a keyboard, mouse, and a few power options in one convenient package.

It was made using a modified Motorola Atrix phone dock and with various 3D printing tools at their disposal. You can lug your Ben Heck Lunch Box to trade shows or anywhere else you need access to an LCD screen and keyboard to plug-and-play dev boards! The design is inspired by the first portable computers which were commonly known as "Lunchbox" or "Luggable" Computers.

Usually when people refer to Linux, they are referring to Linux the kernel, and not the operating system. Linux enthusiast Felix Gardner walks you through how Linux functions as a kernel for an OS of a Linux distribution.

When people install Linux they are usually talking about an operating system that uses Linux as the kernel. The kernel was developed by Linus Torvalds in 1991 and a bunch of people started contributing to it. The rest of the operating system is GNU which is a recursive acronym for GNU NOT UNIX. GNU is a whole host of the software that makes up the entire operating system except for the kernel.
The beginning of GNU dates back to 1983 when Richard Stallman decided to make a UNIX like operating system. UNIX was becoming closed source and Richard wanted to access the software, so he could make changes and manipulate a computer however he wanted. He believed that people should be able to access the software on their computers.
GNU has four essential freedoms:
Freedom 0 - The freedom to run the program as you wish, for any purpose.
Freedom 1 - The freedom to study how the program works, and change it so it does your computing as you wish. Access to the source code is a precondition for this.
Freedom 2 – The freedom to redistribute copies so you can help your neighbor.
Freedom 3 - The freedom to distribute copies of your modified versions to others. By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.
Felix walks you through the subtle difference between free software and open software. He sheds light on the fact that some freeware software is not actually free.

In this segment Felix breaks down the operating system. You’ll find out how the kernel and firmware allow the hardware to interact with the system services, the graphical interface, and the application layer.

Felix scratches the surface of Linux distributions. He goes over the roots for historical reference, Debian which brings you Ubuntu and Raspbian, Red Hat which brings you Fedora, mentions Slackware, and closes with Arch Linux.

Felix goes over the roots of the Linux family tree. He traces the Linux line of succession all the way down to LS or Soft Landing Linux and MCC which comes to you via the Manchester Computer Center. He can't speak to it other than as a historical reference, nor is he aware of whether either one of them is being maintained. There are so many branches of Linux that it would be impossible for anyone to go over all of them in a short segment. However, Felix can and does mention the ones that he finds important.

The first distribution he goes over is the Debian. It's a great distribution to own but you have to be aware that its been adapted and branched out into many different distributions. The one that most people are aware of is Ubuntu and for many people, it's their introduction to Linux and GNU. Another Debian distribution, most people that are aware of because of its association with Raspberry Pi, is the Raspbian distribution. Raspbian is great because it's designed for the Raspberry Pi and very well supported by the Raspberry Pi Foundation.

Slackware is another important distribution of Linux that's been getting some interest these days. Slackware has a shorter lineage than Debian but isn't something that Felix can speak to because he's never installed it or used it for anything. The next distribution of Linux that Felix goes over is Red Hat. Red Hat is developed by a multinational software company that provides open-source solutions to the enterprise community. Red Hat has been influential in setting standards for Linux computing through the industry. Fedora, a very popular distribution of Linux, is brought to you by Red Hat Company. Fedora is the community edition of Red Hat so you know its awesome.

The Final distribution that

Felix walks you through downloading NOOBS for your Raspberry Pi, placing NOOBS on your SD card, and installs Raspbian with the Pixel desktop environment.

In a previous segment, Felix introduced you to a few different distributions of Linux. Now, he walks you through installing an operating system on the Raspberry Pi using the NOOBS installer. In order to use the noobs installer you must first download it. Felix navigates to the Raspberry Pi noobs download page where he presents your two options for installing NOOBS, the NOOBS offline and network installer and the NOOBS lite, network only install.

He drags and drops the NOOBS files onto the SD Card. He takes the SD card and puts it into the Raspberry Pi, connects the screen, the keyboard, gives it power, and then continues with the install procedure.

He gets the Raspberry Pi booted up and walks you through the Noobs installer. The installer gives you some options such as edit config, wifi networks to connect to, and a list of operating systems available to install. In this instance, Felix is going to install Raspbian with the Pixel desktop environment. He clicks on the installer and shows you how long you can expect it to take. Once the operating system is installed, you can configure it to do whatever you want it to do, install additional software, and use the software that’s on there. If you were to configure it as a retro gaming system you could do some retro gaming on it.

Felix goes over disk partitions and file formats. Working from command line, he shows you how to view the disk partitions that are on your storage device and how to modify the file system that they are formatted in.

Partitioning a hard drive divides the available space into sections that can be accessed independently. You can allocate an entire drive to a single partition, or use multiple partitions for dual-booting, maintaining swap partition, or to logically separate data such as audio or video files. The partition table stores the required information. Felix gives an overview of two types of partition tables, Master Boot Record (MBR) and Globally Unique Identifier Partition Table (GBT). The first 512 Bytes of a storage device is dedicated to the Master Boot Record (MBR). This comes from an older partitioning scheme that is designed to work with the boot process of the bios. During the boot process the bios loads the beginning 512 Bytes of the first valid disk in the bios disk order. The Global Unique Intentifier Partition Table (GPT) is a partitioning scheme that is part of unified extensible firmware interface specification. It uses globally unique identifiers (GUIDS), UUIDS in the Linux world, to define partitions and partition types. It is designed to succeed the master boot record partitioning scheme method. GPT is recommended for systems that boot via a UEFI system.

Felix uses a Raspberry Pi and a (Tux the Linux Penguin) USB dongle to demonstrate how this works. He takes Tux and plugs him into the USB. He utilizes command line to locate where his device comes up in the device tree. He uses the command lsblk to shows there are no partitions set up and the device comes up as SDA. He points out mmcblk0 which is the device. He shows you what mounted partitions look like by pointing to mmcblk2, mmcblk7, mmcblk5, mmcblk1, and mmcblk6. He also shows you the device directory which he gets to by typing in ls /dev.

The utility for modifying partit

Felix discusses how file permissions work with Linux. He covers what they mean, what they’re for, and how to set them.

Felix introduces virtual consoles, terminal emulators, and program shells. He traces the terminal emulator to the teletype and discusses how the terminal program emulates legacy hardware connected a mainframe.

Karen makes a simple circuit. This project covers open and closed circuits, switches, incandescent vs LED lighting, and what to check for if it doesn't work.

Felix discusses compositing managers for Linux.=He shows you how to login to the virtual console, how to instantiate instantiate the windows manager, and then follow up with starting just the desktop environment, and then just a single application:

Karen demonstrates the difference between parallel and series circuits by adding additional voltage and another bulb to a simple circuit.

Felix covers the elements of the desktop environment, focusing on windows display managers and display managers. He shares his thoughts on GNOME, Plasma the newest incarnation of the KDE environment, and MATE for fans of classic GNOME.

Karen shows you some projects that you can do with your kids or if you are around someone else's kids. Wigglebots, are so much fun, you can even do them yourself if no kids are available.

In this segment, Felix is going to introduce you to The Linux Manual. The man page is a form of software documentation that is found on Unix or Unix-like operating system.

The manual pages provide a text description of every command available on your system including what they do, how to run them, and what command line arguments they accept. Keep in mind, the manual page has to actually be written and installed on the machine in order to view it.

Felix goes over some of the mechanisms used for account management. He shows you how to create accounts, modify accounts, and remove accounts.

By applying the concept of series and parallel circuits, Karen shows you how to combine a pair of resistors, using Ohms law to calculate the resistance needed to supply the proper voltage to a diode.

Karen illustrates Ohm’s Law by making a simple circuit on a breadboard. To do this she uses two sources of power: a 2- AA battery pack that supplies 3 Volts and a 4 - AA battery pack that supplies 6 Volts to create a circuit that powers a red LED. Karen supplies 6 volts to the LED and demonstrates how it’s not a good voltage for it. If you want to use a 6 volt battery pack but don’t want to damage or burn out your LEDs you’ll need to add resistors to your circuit. In order to figure out how, you need to look at Ohm’s law. Ohm’s Law describes the relationship between voltage current and resistance. You use V for voltage (measured in VOLTS), I for current (measured in AMPS), and R for resistance, measured in OHMS). Current is measured in AMPS, named for a French mathematician Andre-Marie Ampere, the I originates from the French phrase for current intensity, intensite de courant. While current intensity has been shortened to just current, it is still represented by I for intensity.

To make things easier to understand, Karen compares relationship between voltage, current, and resistance to water flowing through a pipe. Using this analogy, voltage is like water pressure, pushing the electricity through the circuit. Current is the amount of water flowing through the pipe. Resistance is the size of the pipe, which determines how much the flow is restricted. If the pressure (the voltage) stays the same and the resistance increases, making it more difficult for the water to flow, then the flow rate (or the current) must decrease. According to Ohm’s law, you need three variables: voltage, resistance, and current. To solve for resistance, you’ll need to find the voltage and current. The red LED is rated for 2.1 volts and 20 milliamps. In order to make

Karen goes over wires and wire tools, and gives advice on selecting the right hand tools to get you started making circuits. Wire is the artery through which electricity flows.

Karen goes over wires and wire tools, and gives advice on selecting the right hand tools to get you started making circuits. Wire is the artery through which electricity flows. Wires come in two types, stranded and solid. If your application requires flexibility, such as in a robotic arm, stranded wire is ideal when the wire needs to be moved frequently. If little or no movement is required, such as when you are prototyping circuits on a breadboard, solid wire is easier to push through.
Solid wire consists of a single strand or core of wire, insulated with non-conductive material. Its cheaper to manufacture and provides mechanical ruggedness, due to less surface area to be exposed to corrosives or environment. A stranded wire tends to be a better conductor than solid wire as the individual wires comprise a greater surface area. It’s good for connection between circuit boards where rigidity could cause stress due to movement.
Electrical wire typically has an insulative cover that has to be removed to access the conductive metal inside. Conductors are materials characterized by their low opposition to electrical flow. Conductive means that electricity can flow through like with metals. Insulators are known for their capacity to stop the flow of current. Electrons flowing through a conductor or wire tend to generate heat. Thicker wires handle the heat better than thinner wires. Thinner wires can even burn up if too much electricity flows through them. Rubbers and plastics used as insulative materials.
Karen goes over different examples of needle-nose pliers. For doing electronics work, small and narrow pliers work best. They allow you to get into tight spots in circuits and they make it easier to manipulate parts and wire. If using very small components, such as sur

Felix shows you how to see what groups are on your system, how to add new groups, how to add users to those groups, and more.

Ben joins Karen to discuss soldering. Soldering is used in electronics to m

The main soldering tools you have as options are your soldering pencils and soldering stations. If you’re just getting started soldering or if you’re on a budget, you can start with a cheap handheld soldering iron. Ben cautions going to cheap on a soldering iron. They start at around 15 watts and go up to 80 watts which is bigger than you’d want to use for electronics. According to Ben, 20 to 40 watts is probably the sweet spot. Wattage refers to the current it draws, which lets you know how much power it has in order to melt solder. The higher the wattage, the more solder it can melt or the faster it will melt it. One thing you need to check for is that the plug for your soldering iron has a ground pin. If a device has exposed metal then it’s good for it to have a grounded plug because that allows static to discharge into the earth instead of building up on your tool. Reasons you’d want to get a soldering pencil is that they are cheaper, they are easier to store, and they come with a stand which you want to be sure to use. You don’t want to set a soldering pencil on the table. Some of the drawbacks include the fact that they don’t have a variable temperature control.
Ben and Karen take a look at three different models of soldering stations. If you’re using a soldering station, you always have a place to store your soldering iron, and many of them come with a place to put a sponge or a brass pad. Each station has some sort of temperature control, how fine that is will depend on the model. The 21-7945 Tenma Soldering Station uses knob control that goes from yellow up to red, so you don’t get the exact temperature. The 21-10115 Tenma Soldering Station has a digital display. Karen likes it because it gives you three preset temperatures but also allows you to fine-tuning of the temperature. Ben notices that it has a transformer in it. This is good because

Felix shows you how to install retropie through terminal and how to drive a TFT screen with the GPIO of a Raspberry Pi.

Ben returns to the learning circuit to demonstrate his soldering technique to Karen. He'll start by soldering a circuit onto a breadboard that turns on an LED light. He then moves the same circuit over to a perfboard

In this segment, Felix continues working on the Raspberry Pi No HDMI build. Previously, he showed you how to drive a TFT screen directly with the GPIO. Now he's going to reconfigure the Linux kernel and enable the GPIO keyboard matrix module.

Karen breaks down the science of how electricity. She’ll go over Coulomb’s law, use magnets to help visualize how polarity works, and break down how polarity works on an atomic level in an electrical circuit.

We use electricity everyday in our homes. Devices plugged into the wall are powered by AC electricity. Handheld devices like our smart phones are powered by DC electricity. Electricity for our devices comes from outlets in our walls and from batteries but how does that work? How does electricity get from one point to another? To explain how electricity works, Karen starts with the most basic parts. Everything, all matter, is made up of atoms. Atoms are made up of particles consisting of protons and neutrons in the core, surrounded by electrons. In an atom, protons are positively charged, while electronics are equally negatively charged. Atoms normally contain the same number of protons and electrons. If this is the case, these atoms are electrically neutral, having no charge. However, this can be changed. An atom can gain or lose an electron by passing it to or from another atom. This causes an atom to become an ion, meaning it has extra or is missing electrons. If an ion has extra electrons it is negatively charged, while an ion with missing electrons is positively charged. Charged ions exert force on each other.

Felix unboxes the Pi-Top. Included are guide booklets, an inventor’s kit, a Raspberry Pi (optional), a box of accessories, and the power supply. There’s also a Pi Top pulse accessory which has also been included.

The Pi-top is marketed as a kit for kids to learn about computing. Felix goes into the box of accessories and finds s buttons, potentiometers, jumper cables, and a breakout board. Felix compares the Pi-top with its previous iteration. He takes out the cooling bridge. It’s a heatsink but it also ports over the GPIO to a header located on the hub. He shows you how to plug the Raspberry Pi into the hub. It’s going to supply power, and give you HDMI. It also connects to the cooling bridge and the breakout board.
Now that he’s shown you how easy it is to put together, he’s ready to take it apart. He starts with the hub and then precedes to voids the warranty by removing the ribbon cable and prying off the rails. After snapping off the parts, he admires the included battery bank. Next, he takes apart the screen. The screen pops out after he loosens the ribbon cable. Some of the parts that he finds included in the hub are the ATtiny 88, a multiplexer demultiplexer for the GPIO, and for video there is an HDMI to embedded Display Port converter. For the battery there is a lithium-ion battery integrated circuit and a gas gauge. Felix admires the battery pack. On the Pi-top proto plus, Felix discovers an ATtiny 20.

In a previous segment, Karen showed you how to make a simple circuit using an LED. Now, she’s going to apply that to a fun project by showing you how to make an edge lit sign. To make an edge lit sign you add scratches to a piece of acrylic. Those scratches will interrupt a beam of light from an LED and show your design

Karen is using acrylic that is 0.1 inches thick. You could also use 1/8 inch or a similar thickness. You don’t want to go to thin, because then it might break. You don’t want to go too thick because it’ll be difficult to deal with. When deciding the size of your acrylic, you want to stick around two to three inches in either rectangular or square. If you go too big, the light of your LED won’t reach your design, and it won’t light up very well. For this particular application, if you’re only using one LED, then you want a smaller design.

When drawing your design, you want to make sure that your lines are not going to be too thin because there will not be enough mass to catch the light significantly to really show off your design. When you make your design you want to make sure that you’re using nice, bold lines. Karen draws extra lines within the border of the acrylic. This is because when it’s done, she’s going to be putting aluminum tape around the edges, and this is to make sure that the design isn’t covered up later. When her design is done, she tapes the acrylic down so that it doesn’t shift, and so she can get good alignment between the acrylic and her design.
Next, you’re going to want to etch your design. You can use an exacto blade or any kind of hobby knife that has a sharp pointy end. She suggests using electric etchers if you have a child doing this. For her example, she etched in a few different techniques so she could show you the differences of direction of scratch and how it affects your design when you place your LED. She goes over some of her different etching techniques. She suggests d

The pi-top OS is great for learning to code using Python, discover Scratch, or to have fun while interacting with electronics. It also comes with some really great kits.

In this segment, Felix boots into the Pi-top OS and goes through initial setup. After selecting his preferences he goes over the tour of the desktop. He also introduces you to the pi-topCODER, a learning tutorial on how to interface with the GPIO using Python.

Felix opens up the terminal to learn more about the OS. The pi-top runs a modified version of Raspbian called Polaris. The Polaris OS is basically the same as Raspbian except that it’s been modified to accommodate the additional hardware and include the pi-top dashboard. You can get anything you want from the dashboard through the menus. Felix goes over the programming menu option which supports several coding environments for Python, Java, Scratch, and Sonic Pi. He walks through some of the other menu options such as what’s included with Office, Games, and Settings. He returns to the desktop and demonstrates how you would use the built in pi-top coder to create a circuit using a breadboard.

Circuit Blocks are a great DIY beginners electronics project, more robust and durable than a simple circuit using cardboard and paper clips. It involves more complex components giving you more opportunities for fun and learning while experimenting.

This is a great, DIY Beginner electronics project good for elementary school levels and up. I’ve even had Pre-K children use these, but most of them still needed a little help. For our circuit blocks, we’re going to include three main types of components: power sources, loads, and interrupts.

The power sources we’ll use will be batteries, which provide DC power or direct current power, meaning a current that flows in one direction. I recommend 2AA 3V battery packs, and maybe a 4AA 6V battery pack. You could even use a 9V battery and clip if you’d like. You’ll need to be careful with more than 3V, but I’ll explain why later.

The load in a circuit is anything that consumes power. We’ll be using LEDs, motors, buzzers, and fans. You can also use incandescent lights from either strand holiday lights or buying sockets that hold bulbs. Ideally you’ll want components that are rated for around 3V and for DC power.

For motors and fans, they may be rated for more power, but try to get as low as you can near 3V. These motors and fans can handle more power, but will still work at 3V. Most LEDs are rated for 1.5-3V DC. Be careful with the LEDs. If they are fed too many volts, they’ll burn out and stop working. While that’s true for most components, LEDs tend to be less tolerant to voltages above their rating. We’ll also make blocks with interrupts, like buttons, switches, and potentiometers.

Felix reviews the connections between the Raspberry Pi, the TFT adapter, and the button matrix for the Raspberry Pi No HDMI projects.

Felix revisits the Raspberry Pi no HDMI project. There were quite a few questions on the community regarding the GPIO connections between the Raspberry Pi and the TFT along with the button matrix. The github repository for this project includes the bill of material, data sheets, enclosure, OS setup, and schematics. In there you can find the GPIO set up, along with a spreadsheet for the GPIO connections, under the OS set up. A good reference for this can be found at www.raspberrypi.org/documentation/hardware/raspberrypi/dpi/README.md. There you can find a chart that shows the different modes that can output the display through the GPIO.

They are using the 565 configuration for the TFT display. It opens up GPIO 27 to 20 for the button matrix. The connections they go with for the TFT screen are GPIO 27, 22, 26, 23, 24, 25, 20, and 21. Finally, Felix shows you where to look for the connections on the Raspberry Pi itself.

Felix takes a look at a security vulnerability that he opened up allowing remote login over SSH as root. He closes up the security vulnerability and shows another way to access files over the network in a more secure manner.

Karen walks you through the Spaceship Interface project which is included in the Arduino Starter Kit book.

For this project you’ll need an Arduino Uno the USB cable to plug into your computer, breadboard, jumpers, a tact switch, two red and one LEDs, three 220 ohm resistors for the LEDs, and one 10 kiloohm resistor. The code you’ll need to do this project is included in the Arduino Starter Kit book.

The Arduino Starter Kit book includes circuit diagrams and code which is referred to as sketches. A sketch includes a set of functions followed by curly brackets, such as void setup () and void loop (). Anything you put in the curly brackets is the code that is executed when the function is called. Sometimes you will need to create what are known as variables for your code. A variable are items that you want your code to remember so that you can reference them later. One good thing about variables is that if you use the same variable throughout your code and need to adjust the value of the variable, you only need to set the variable to another value at the top of the code. Karen shows you how to set an integer as a variable for the project.

After defining the variable, Karen moves along to the setup code. The setup is where we configure the pins so that the Arduino knows what’s an input, what’s an output, and which pins we’re using. In her code the 3 LED are designated as outputs, for pinMode, and the button is designated as an input for pinMode.

Since 2011 this channel has been your one stop shop for amazing builds, exclusive mods and cutting edge ideas. And element14 has no intention of that stopping.

Stay tuned because we'll be continuing to deliver fresh videos every Wednesday and Friday specially made for you by a new team of talented electronics enthusiasts.

Felix goes over some basic and essential security configurations for the Raspberry Pi. Modifying the security settings of the Raspberry Pi will allow you to connect to the network more securely.
Felix goes over modifying the sudoers file. This file manages how sudo is invoked and what groups or accounts are bestowed with the privileges of sudo. A secure practice is to require an account with sudo privileges to supply a password when calling any program with sudo. Some system administrators like to require anyone logged into the account to also know the root password. The only thing Felix is requiring is for the person to know the passphrase for the account in the sudo group.
He also shows you how to create a new key pair. A key pair consists of a public and a private key. He starts by issuing a key gen instruction via SSH. He then shows you how to install and setup fail2ban. Fail2ban is a service that can track failed attemps to the SSH port and if an IP address fails repeatedly, the IP address can be blocked for a period of time, or indefinitely. In the comments below let us know if there is anything related to security that you would like us to go into more detail about.

Switches are used every day to control electronics and electrical devices. They can be used to turn devices on or off, as well as, to send signals.

Karen demystifies a variety of switches including push button switches, slide switches, dip switches, rocker switches, toggle switches, rotary switches, and snap action.

Felix gives a basic introduction to 3D design in a Linux environment using a tool called FreeCAD. FreeCAD is a multi-platform parametric 3D modeling program that supports many 3D formats.

Karen works on a Wire Maze game. Move a loop from one end of the maze to another without letting them touch. If they touch, you lose.

There’s a second switch for selecting the mode you want. ,She uses a SPDT switch that is On-Off-On so you can select either setting, but still turn the game off. To make the circuit she puts the wire loop and maze after the battery pack, but before the mode switch. After the mode switch, the LEDs and the speaker are in their own circuit, each connected to one of the terminals on the switch.

Felix does something different and focuses on hardware. He field strips the Raspberry Pi A+ by removing the GPIO, USB port, MIPI camera interface (CSI) connector, HDMI, and composite video, leaving the power and SD slot in place.

DaftMike builds a thermometer using an Arduino and a thermistor. He’ll write some Arduino code, build a circuit, and then convert the values into a temperature reading. He’ll use an NTC thermistor as a sensor, a breadboard, wire, and a 100K resistor.

He’ll use an Arduino Micro because it plugs directly into the breadboard but you can use any Arduino you like for this. He uses wire to connect 5 volts to the top power rail and ground to the bottom power rail. There are usually multiple ground pins (marked ‘GND’). You can connect to any of these. He connects the thermistor to 5V and in the same column he connects the resistor to ground. It doesn’t matter which way around these components go, they work either way. Finally, you connect midpoint to analog pin p0. You can now write some code.
He names the thermistor pin and sets up an array to store a bunch of readings so that you can take an average to sort out the data. He uses a line to set up the serial monitor. In the main code he declares the output as a float and then uses a for loop to calculate the average. A thermistor reading is stored in the array, added to a running total, and then delayed for a while to give the ADC a chance to settle before it runs through the loop again. ADC stands for analog to digital convertor. It converts voltage on the analog pin into a discrete signal. Outside that loop, the code divides the running total by the number of readings to get an average. You can then print it to the terminal.
DaftMike gives a diagram of the circuit. It’s a voltage divider where R1 is the thermistor and R2 is 100K. The equation for voltage dividers is Vout = Vin *R2/(R1+R2). Vout is what we measured in the code, Vin is 5 volts, R2 is 100K, and R1 is what we are solving for.

Ben introduces DaftMike, one of the new hosts of element14 Presents.

Ben Heck introduces Clem Mayer, one of the new hosts of element14 presents. Got a question for Clem?

In this episode of sudo Sergeant, Felix takes a look back at past episodes of sudo Sergeant and answers community member’s questions from the comments section.

DaftMike built a thermometer using an Arduino and a thermistor. He expands on this to show you how to build a temperature controlled fan for your desk. It monitors the room temperature to see if it gets too hot. When it's too hot, an Arduino turns on a fan that cools you off!

DaftMike goes over the code from last time. It reads a thermistor and prints the temperature to the serial monitor. He moves all the equations he wrote earlier into four separate functions. A function is like its own little program. In Arduino code there is always a setup and a loop function. The setup is at the start and only runs once. The loop comes after that and repeats continuously. Taking the equations from last time, he re-writes them so that they each have their own separate function. The main loop uses these functions to execute the code. Structuring your program this way makes it easier for you to reuse parts of your code. For example, if you wanted to add another temperature sensor then all you would need to do is call these functions again and pass them a different value. It saves you time as well as some program memory. For it to work, he’ll need to add a couple more functions. One for turning the fan on and one for turning the fan off. He’ll also need to set up the built-in LED as an output to stand in for the fan during testing. When that is done, he tests the code.

After testing the code, he notice that when the temperature gets close to the trigger point it flashes. This is not what he wants. The way to fix this is to add what’s called hysteresis. Hysteresis is the dependence of the state of a system on its history. It’s when the output of your system, in this case the fan or the LED for now, lags behind the state of your input, which in this case is the room temperature. Returning to the code, instead of a single trigger point, he’s set some thresholds to check. There’s a high threshold and a low threshold. As long as one number is lower

Karen explains what resistors are, how resistors are represented on a schematic, various types of resistors, and the characteristics of those resistors. She’ll go over carbon composite resistors, thin film resistors such as carbon, metal, and metal oxide film; thick film or cermet resistors; wire round resistors; variable resistors such as thermistors, potentiometers, and photo or LDR resistors; SMD resistors; trimmer pots; and more.

According to Ohm’s Law, in every circuit there is a balance between voltage, current, and resistance. Most electrical components require a certain voltage and current to function properly. By adding resistors, you can control the voltage and current in various parts of a circuit. Resistance in an electrical circuit is when a material prevents some or all of the electrical current from flowing through it, converting that restricted energy into heat. Every material has some resistance. In resistors, this principle is used to create a controlled amount of resistance that can be used to regulate circuits. Resistors can be made of a variety of materials. Carbon composite resistors are made by combining a conductive material, usually finely ground carbon or graphite, with a non-conducting material like ceramic. Once widely used, they have mostly been replaced by more efficient and precise resistor types. While cheap to produce, their lack of use means they are often more expensive. Carbon film, metal film, and metal oxide film are examples of thin film resistors. Thin film resistors are generally made by depositing a conductive material onto an insulating ceramic rod or substrate. A laser trimmed pattern is cut into the film in order to increase its conductive or resistive path. The resistance value is controlled by varying the thickness of the film. Thin film resistors are the most common type of through-hole resistors. Surface mount resistors are created using the same method as thin film resistor. Surface mount resistor

Ben Heck introduces Matt Eargle, one of the new hosts of element14 presents.

Felix gives an overview of the schematics used for the Pocket Bagle bela.io Drum Sequencer using KiCad. He'll also let you know what he likes about using KiCad circuit design software, how to work off of a Pocket Beagle template for your design, and what you need to know to get started.

There are six different schematic sheets for this build. There are schematics for the Bela PocketBeagle Connections, the 3 Digit 7 segment Display, the LED matrix, the Button Matrix, the Power and Motor Driver, and the Analog and Amplifier.

Solder fumes can be harmful to your health. Luckily, Karen has a solution. Build a desktop fan that keeps solder fumes away. You can salvage any old fan, as long as it’s DC, for this to work. To build this circuit, you’ll also need a nine volt battery or a twelve volt power supply, a power switch, an LED, and a resistor. You’ll need the resistor to power the LED, which means you’ll need to know the resistance value. Karen goes over calculating the resistance value to use either the 9 volt or the 12 volt power supply.
To build this circuit, you’ll also need a nine volt battery or a twelve volt power supply, a power switch, an LED, and a resistor. You’ll need the resistor to power the LED, which means you’ll need to know the resistance value. Karen goes over calculating the resistance value to use either the 9 volt or the 12 volt power supply.

To build this circuit, you’ll also need a nine volt battery or a twelve volt power supply, a power switch, an LED, and a resistor. You’ll need the resistor to power the LED, which means you’ll need to know the resistance value. Karen goes over calculating the resistance value to use either the 9 volt or the 12 volt power supply.

The resistor will go in line with the LED. Since this fan is rated for a voltage equal to or higher than the supply voltage, I don’t need to add any more resistance. I also want to be able to control the speed of my fan. This would normally be done using a 555 timer or another chip using PWM. To keep the circuit simple, we’re going to use just a potentiometer instead. It’s not the most efficient way to build this circuit, but it works. Potentiometers are variable resistors. If put in line between the battery and the fan, by adjusting the resistance, we also adjust the amount of voltage supplied to the fan, making it go slower or faster. If we put the LED indicator in series with the motor and potentiometer, it would also be supplied a varying voltage, which would ca

Felix walks you through the steps for installing Arch Linux through terminal. He’ll show you where to download the installer from archlinux.org, how to mount the Arch Linux installer to a USB, how to configure the bios to boot into the USB, and goes through the rest of the install process. Once installed, you’ll be able to login and customize the OS through the GUI.

We take a look at two different types of monochrome LCD and hook them up to an Arduino. LCDs are useful for when you need to display some information, and with plenty of existing code to help us out, they can be added to almost any Arduino project.

Ben Heck introduces James Lewis, aka Bald Engineer, one of the new voices of element14 presents.

In this episode of The Learning Circuit, we add an LCD to an earlier Arduino project. We also look at how to do state change detection and reading the position of a potentiometer.

In this episode, we learn how to read resistor coders to learn the values of resistors. You’ll also learn how to differentiate through-hole resistors and surface mount resistors, as well as, determine the values of four band and five band resistors.

There are through-hole resistors and surface mount resistors. Through-hole resistors have color bands on them. Resistors use a color coding system to indicate their value as well as their tolerance. Tolerance is the accuracy or margin of error of the resistor rating. This can Range anywhere from a fraction of a percent up to 20 percent. You can use the color coded resistor chart below to determine the digit multiplier or the tolerance that the color band represents.

Resistors with a single black band are zero ohm resistors. Since they have the same packages as other resistors they can easily be placed on a PCB by automated machines. They’re often used as wire simply to connect traces. Karen shows you how to figure the values of some four and five band resistors.

Solder along with Karen as she shows you how to review resistor codes using a substitution box. The kit is useful for prototyping resistors.

Once assembled, it can be used on an array of resistors, ranging from 10ohms to 1 mega ohm. The kit includes the knobs to switch from ohm to kilo ohm, a PCB, a bag of resistors, and the parts for the enclosure. It also includes a manual that gives you the placement of the resistors on the PCB, its value, and its color code. Karen is going to show you how to figure these out manually.

We’ve all been there before. A corrupted hard drive that doesn’t allow you boot in. Felix shows you how he repaired his corrupted disk drive in a Linux environment. He’ll show you can do this by plugging it into a different machine, and taking advantage of Terminal to repair the system file on it.

Karen goes over how diodes work and shows you what happens when you hook it up to a power supply in a circuit.

Diodes have two axial leads coming out of both ends with a stripe in the middle to indicate which end is the cathode, or the negative end. A diode is an electrical component that allows current to flow in one direction but not the other. Diodes are made with a semiconductor material, mostly silicon but sometimes other materials such as germanium, selenium, or gallium arsenide.

Semiconductors typically have four valence electrons in their outer shell. Silicon, being a semiconductor, also has four outer valence electrons. This outer shell can hold up to eight electrons. Electrons are most stable when their outer valence shell has eight electrons, a rule known as the octet rule. Each silicon atom shares an electron to its neighboring silicon atom in order to satisfy the octet rule. When silicon atoms form covalent bonds they crystallize into a very strong structure known as a crystal or a lattice.
In the P-type region silicon is doped with boron or gallium. Boron and Silicon have only three outer electrons. When mixed to a silicon lattice, they form “holes” in the crystal structure electron has nothing to bond to. The absence of electrons gives it a positive charge. In the N-type region silicon is doped with antimony, phosphorus, or arsenic. The fifth electron becomes a free electron. It is free to go wherever the current takes it. These free electrons are negative charge carriers.
The point where the N-Region and the P-Region meet is called the PN Junction. Near the junction the positive charges and the negative charges, having opposing charges are drawn to each other like magnets. The free electrons in the N-type region migrate over and fill the holes in the P-type region. Because of the charged particles moving around, the area near the junction in the P-type region becomes slightly negatively charged while the area near the jun

In today’s episode, we’re going to make a project using Diodes and Logic. Karen wants to build a skylight where there four LEDs, a white one for the moon and three colors (green, blue, and purple) for three different clusters of stars.

It will have three switches. If switch one is on, then the green stars and the moon will be on. Blue and purple would be off. If switch 2 is on then the blue stars and the moon will be on. Green and purple would be off. If switch 3 is on then the purple stars and the moon is on. Green and Blue would be off. To make this happen we’ll need some diodes and to draw out our circuits to see how we’ll have to wire it up, to make it work.

In this episode, Karen reviews p-in junctions and talks about how they differ from other types of common diodes, such as schottky diodes, zener diodes, LEDs (light emitting diodes), laser diodes, and photodiodes.

P-N junctions are considered your typical didoes. They have a p-n junction with a threshold voltage that has to be reached before current will flow through them. In silicon diodes, this is 0.7V. Once this is reached, the current will continue flowing. When hooked up backwards, in reverse bias, these diodes do not allow current to flow. If a diode is reverse bias, and it’s supplied with too much voltage, more than it’s breakdown voltage, it’ll “break-down” and current will flow through it in the wrong direction. Schottky diodes often look like typical diodes. But unlike p-n junction diodes, Schottky diodes have a metal-semiconductor junction. Silicon diodes require time for their depletion zone to grow and shrink when switching from allowing forward current to blocking reverse current. There’s a recovery time. Schottky junctions have no depletion zone. Because of their metal-semiconductor junction, Schottky diodes require virtually no recovery time and therefore have much faster switching speeds. This means they can handle switching current better and faster, which makes them useful in high frequency applications.They also have a lower forward voltage drop. Silicon diodes have a voltage drop of around 0.7V, but the voltage drop of Schottky diodes is between 0.15 V and 0.46 V. This means they lose less energy to heat, making them more efficient. Schottky diodes are not useful for all applications, as they can leak a small amount of current backwards. This could be problematic for certain circuits. While Schottky diodes can let some voltage leak through backwards, zener diodes are designed to allow current to flow in both directions. The p-n junction of zener diodes is heavily doped, only a specific voltage, the Zener voltage (Vz) can pass thro

Karen shows you how to build a laser beam projector. It will use a laser diode and two motors with mirrors attached to their shaft so that the mirrors are are spinning. C

When the laser beam hits the first mirror it turns it into a circle. That circle gets reflected off of the second mirror and it's projected onto the the wall into a kind of spira trap shape. Potentiometers will allow you to adjust the speed of the motors so that we can adjust how fast the spirograph is spinning.

Karen discusses transistors. Rather than using a physical, mechanical switch, a transistor can act as an electronic switch, using signals to turn it on or off. She'll go over what they are, how they work, and some types of transistors. She covers Bipololar junction transistors (BJT), NPN transistors, PNP transistors, and darlington transistors.

Previously, we’ve talked about how diodes work. Silicon diodes have a p-n junction. Bipolar junction transistors or BJTs are bipolar because they have two p-n junctions. BJTs are essentially two diodes in a single package. The two main types are NPN and PNP transistors. NPN transistors have two n-type regions on either side of one p-type region, while PNP transistors have two p-type regions, on either side of one n-type region. Bipolar transistors have 3 leads, one going to each region. Typically, the middle layer is the base. P-type in an NPN, and n-type in a PNP. One of the other layers form the emitter and the third, the collector. These are labelled B, E, and C. On the circuit symbol, the arrow is always on the emitter, so we can tell which lead is the emitter and which is the collector by seeing which one has the arrow. The NPN transistor symbol has an arrow on the emitter pointing out, while the PNP transistor symbol has an arrow on the emitter pointing in. Transistors act as an electronic switch, conducting current across the collector-emitter path when a voltage is applied to the base. The switch is off if there is no base voltage present. When base voltage is present, the switch is on. We know from our diodes lesson, that diodes require a forward voltage of 0.7V before they are turned "on" allowing current to flow. In a standard NPN transistor, when 0.7V is applied between the base and the emitter, the transistor “turns ON”, allowing current to flow from the collector to the emitter. With an NPN transistor, we normally bias the device so that the collector voltage is positive with respect to the emitter.

After years of having brothers and coworkers sneaking off with her candy, Karen is using her new knowledge of transistors to create an alarm to protect her sugary treasure. Make along with Karen an alarm using a photoresistor, buzzer, and transistor!

Karen gets into the nitty gritty of how capacitors, explaining how the metal plates a dielectric manipulate electric charge to store energy. Learn about what materials are used to make capacitors, how to read their values, and what happens when they are put in series or parallel.

Karen makes the Capacitance Substitution Box Kit. It can be used to temporarily substitute for a capacitor in your circuit, or be used to test varying capacitances to see which suits your project best.

Solder along with Karen and see a brief practical example of the differences between capacitors of lower and higher value.

In this episode, Karen talks about the two common types of field-effect transistors, MOSFETs and JFETs. Find out the differences between them, and what it means for them to work in depletion and enhancement modes.

Today we’re going to use MOSFETs to make a phase light. For this project, we’re using two n7000s, which are n-channel MOSFETs.

In electronics we use maps called circuit diagrams as a graphical representation of the connections and components in a circuit. Follow along with Karen as she goes over common circuit symbols and how to read them on a schematic.

Follow along with Karen as she walks through reading a schematic and turning it into a functioning circuit. The application of the finished circuit has endless possibilities. Make a dancing robot or a toy with flashing LED eyes, all activated by sound!

In a previous episode, Karen gave an overview of Transistors. James Lewis, the Bald Engineer, is a special guest. They'll revisit some of the topics presented last time, make corrections where necessary, and share their findings with the rest of the community!

Digital multimeters, or DMMs, come in many shapes and sizes. In this video, we compare a Pen Style DMM to a larger more traditional meter. Both have 3.75 digits of resolution, but how do real-world voltage, resistance, capacitance, and diode measurements compare?

Inductors are used in so many electronics, you're likely surrounded by them and don't even know it. Find out how electricity and magnetism are made to work together to make your electronics more stable and efficient in this weeks video about inductors.

When tearing down a product, you will need a screwdriver and plenty of bits. Duratool has you covered with this cordless screwdriver set.
In this review, James takes apart a 40-year-old oscilloscope with the help of a cordless screwdriver, some magnetic trays, and a variety of pliers. See inside this antique and see if your bench needs an upgrade.

Learn how to get more bang from your battery by using an inductor to make a battery juicer that can run a flashlight off a single, used battery.

After a multimeter, a soldering iron is the most useful tool in electronics. In this episode, James looks at potential upgrades to your soldering station. Whether you have no iron or a complete re-work station, this video introduces you to possible upgrade options. For example, are you looking for a Weller WES51 alternative? You might consider upgrading to the WX professional series. Get the B.O.M. and connect with James on element14: http://bit.ly/2FHw09r

Capacitors are a seemingly simple device. In this episode, James goes deep into what makes polymer capacitors different from other capacitor types. Spoiler alert: it is a material found on the cathode side of the capacitor that makes a polymer, a polymer. Additionally, he covers what to consider when trying to switch from a multilayer ceramic capacitor (MLCC) to a polymer. Get the B.O.M. on the element14 community: http://bit.ly/2UlyRrY

We've learned about how electricity and magnetism work together in inductors. Now see how those same coils and forces are used to turn electrical energy into mechanical energy in motors. Connect with Karen on the element14 community: http://bit.ly/2HzCGYW

Polymer capacitors offer low ESR and high capacitance in a small package. See what happens when a tantalum polymer replaces an MLCC in a DC-to-DC converter. Or, check the result of replacing a traditional electrolytic capacitor with an aluminum polymer. For fun, James shows measurements on a modern switching power supply and goes back to a classic 8-bit favorite, the Commodore 64.

After hours of playing Breath of the Wild on her Nintendo Switch, Karen decides to make her own Korok mask, complete with spinning pinwheel. Watch as Karen makes a pwm motor controller circuit and uses a force sensitive resistor to bring this Zelda mask to life.

Need to rework through-hole components? Check out this Weller WX-Series soldering gear. It includes a 120 Watt de-soldering iron (WXDP120), 65 Watt (WXP65) iron, and a larger 120 Watt (WXP120) iron. James re-caps a Commodore 64 with the help of this WXR3 soldering system. It takes no time to remove components like capacitors and swap them in with modern replacements. As a bonus, he ends the video by re-working a Raspberry Pi to have a socket header instead of pins!

After doing an overview of the various types in an earlier TLC episode, Karen returns to the topic of switches to clear up the confusion involving poles and throws and to talk about how inductors factor into relays.

When it is time to rework a board with surface mount components, you need more than a traditional soldering iron. Learn how tools like Weller's WX-series can be used to remove parts from a board quickly and easily. See how the Bald Engineer uses hot air to rework circuit boards he has made in the past. He also repeats one of the first electronics hacks he ever did.

Many homes have lights that can be turned on by more than one switch. Karen goes over how these switches work and how to wire one into your project circuit.

An overlooked danger of electronics soldering is the fumes. While the smell and smoke may not be pleasant, the chemicals in the fumes can be harmful. Is solder made with lead your only concern? Learn about where lead-free solder came from, what different flux types mean, and two ways to keep your air (and your lungs clean.) The main product featured is the Weller Zero SMOG EL.

Time to learn about electronics that produce and interpret sound. But before getting into the electronics, it’s good to first understand how sound works. When a sound is generated, a vibration is produced that pushes and vibrates the surrounding air which continues and is carried through the air until it reaches our ears or other devices that can interpret sound.

Even with high-quality genuine tips from a brand like Weller, your tip does not last forever. These 5 useful tips address common soldering iron maintenance questions. Answer questions like: should soldering iron tips last forever?:

The last episode we learned all about sound components, those that make them and those that interpret them. In this episode, Karen assembles as Velleman MK171 Voice Changer kit. She walks you through the instructions, reviewing symbols, components, and concepts learned in previous episodes. This circuit has uses 2 IC chips, LM386N op-amp, and an HT8950, voice modulator chip. When sound is interpreted by the microphone, the signal goes through these ICs, is processed, and changed to modulate the user’s voice. Using the tac switch buttons on the PCB, the voice can be changed, adding vibrato, adjusting the pitch up and down, or made to sound like a robot. The circuit also includes variable resistors that allow for changing the microphone sensitivity and the speaker’s output volume. Batteries and speaker not included.

The TENMA portable power supply (72-2660) offers bench supply capability in a backpack friendly package. The single output is capable of 45 watts with up to 30 volts and 3.75 amps out. The built-in USB ports offer an easy way to power 5 Volts Arduino or Raspberry Pi projects while limiting their current. See how this portable supply performs, the things the Bald Engineer likes about it, and the points to consider before buying.

A new console has launched, so there is only one thing to do with it - take it to pieces! Is this a new console? What has changed? What can we learn about the future of the games consoles?

Any circuits that have more than the most basic of functions requires a little black chip known as an integrated circuit. Integrated circuits, or ICs, fall into 3 categories, analog, digital, or mixed signal.

Analog signals can vary in the entire range between the minimum and maximum signals. In the case of this graphic, any voltages between 0V and 5V.Digital signals are typically on or off, high or low, represented by a 1 or 0.

Analog ICs are most commonly used for regulation or amplification. Since sound, voice, and music signals are typically analog, they frequently make use of analog ICs.

Digital signals, being much simpler as only having two states, allow for the sending and storing of data much more easily and efficiently.

Some ICs have components that allow the conversion of analog and digital signals from one to another. These are known as mixed-signal ICs.

Follow along to learn about voltage regulators, op-amps, logic gates, 555 timers, microcontrollers, ROM, RAM, and more.

Tearing down a design classic, the iMac G3. Looking at how they fit everything into an "all in one" form factor, and the POWER PC architecture. Will there be any compromises in design to make it all fit?

Electrostatic Discharge (ESD) damage can occur without you knowing it. That’s bad. However, the good news is that with little effort you can prevent it. Duratool has a kit of the most common ESD tools for any electronics workbench. It includes a large mat, grounding cable, wrist strap, ESD-safe cleaner, and a simple electronic tester. Don’t get shocked by ESD; add these simple tools to prevent it.

In the previous episode, Karen did an overview of integrated circuits or ICs. This week, Karen chose an electronics kit that contains two ICs, a phase locked loop, and a ripple binary counter.
A phase-locked loop takes one external input and one internal input, comparing the frequencies of their signal and turns that difference into a voltage that goes back to adjust the internal signal. This process continues until both external and internal signals are equal. This process generates an output signal that slowly changes then stabilizes. In today’s kit, an electronic dice kit, that signal from the phase-locked loop IC is used as the clock input signal of the second IC, the binary counter.

In 1998 the big Christmas toy was an interactive animatronic pet. How intelligent was it really? What hardware was crammed into the fluffy exterior? I guess there is only one way to find out - tear it down! http://bit.ly/2Xls86m

The ICs are:
An LM234 Adjustable current source (a power controller)
an HT93LC46 - 1K EEPROM (non-volatile memory, or its storage)
an IC with smudged text - although I understand it is an audio amplifier!
and 2 potted ASICs which I understand is the CPU and ROM.

An obvious measurement for a capacitor is its capacitance. However, knowing its ESR is critical in design work and an important troubleshooting clue. Capacitors with high ESR can cause significant ripple voltage and can indicate a capacitor near the end of its useful life. The Atlas ESR70 makes quick work of measuring a capacitor's ESR.

Back on the Ben Heck Show, a viewer requested a real-life build of the game from Jumanji. Since magic isn’t real, the team decided to make a game based on logic gates. After spending months helping Ben try to work out their game, “Logic Bomb”, Karen got a taste for digital logic using logic gates and has been itching to get back to the tricky subject that continued to stump her. This episode covers 7 types of logic gates: NOT, AND, NAND, OR, NOR, XOR, and XNOR. Using truth tables and analog circuits, Karen tries to break down the logic to help you understand the literal ins and outs of each type of logic gate:

Not only is tearing down a sewing machine a new experience for me, but we have a computer controlled one. To make things even more interesting, this one is also 24 years old - or so I thought!

A multimeter is a go-to tool for electronics measurements. Knowing how to use it to measure voltage, current, diodes, and transistors can save time (and frustration) while troubleshooting. James explains how the multimeter works so that you can understand what it is doing while using it.

In the previous lesson, Karen explained the logic behind AND, NAND, OR, NOR, NOT, XOR, and XNOR logic gates. In that episode, we also learned that logic gates are typically contained in IC chips, with multiple gates within each chip. For this episode’s project, Karen has decided to throw out the ICs, and instead, use transistors to create each logic gate, further demonstrating how the logic of each gate type works. Follow along to continue the journey of understanding logic gates through the use of transistors. Solder along and you’ll end up with a tidy little project contained within a couple of Altoid tins! In the end, Karen dares you to try your hand at creating the more complicated XOR and XNOR gates out of transistors. Are you up to the challenge?

What was home gaming like in the 1970s? How different were the consoles compared to today's models? What significance did the 1970s show us for the future of computing?

The PEAK DCA Pro is a compact semiconductor analyzer. The DCA75 finds pinouts, determines specs and does curve tracing. Oh, and it is fast. In this video, James shows how well it works with BJTs, MOSFETs, LEDs, and even Voltage regulators.

Things are starting to get complicated. In a previous episode, Karen talked about logic gates and digital logic. In this episode, Karen dives into the more complex, combinational logic devices: multiplexers, demultiplexers, encoders, and decoders.
Multiplexers and demultiplexers can be thought of as traffic controllers. They take their inputs and effectively “flip digital switches” in order to route the signals to various outputs. The main difference between the two is that multiplexers take multiple inputs and select which to route to a single output, while demultiplexers take a single input and select which of multiple outputs to route it to.
Encoders and decoders are used for more complex applications. They take one form of data and translate it into another form of data. Different varieties work with binary, decimal, binary-coded decimal (BCD), logic level, and 7-segment.

Tearing down not one, but 2 Big Track programmable toys. The original released in 1979, and the modern reproduction from 2019, how different are they? How have the techniques changed? Are there any useful tips we can use in our own projects?

A bench power supply makes powering circuits easy and safe. Learn how to adjust basic controls like voltage. Finally, see how "current limiting" works. See how you can use built-in series or parallel tracking to increase a bench power supply's voltage or current output. Last, if you are in the market for a power supply, do not forget to add some leads like mini-grabbers, alligator clips, and banana plugs.

Karen walks through how to use one type of decoder in a circuit, a BCD to 7-segment. While this circuit would typically use a microcontroller to provide the four necessary input signals, Karen’s circuit uses 4 switches to allow the user to manually input the BCD number. This circuit is helpful for practicing counting in binary as well as learning how to drive a 7-segment display.

This circuit uses a common-anode 7-segment LED display that is driven by an SN74LS47N decoder. If you would like to create a circuit using a common-cathode LED display, a 74LS48 decoder could be used and the power would need to be flipped

We compare the inside of a 1988 1G carphone to its 2013 great-grandchild. Other than a big color screen, what else has changed? Let's teardown both to take a look.

An Electronic load can sink current from power sources such as power supplies or batteries. Loads are useful to test a power supply’s design margin or verify a battery’s capacity. See how three different instrument options from ultra low-end to midrange to high-end compare. Learn how modes like constant current and constant resistance can be used for different measurements.

Another new mid-generation release, so what's new? Is it worth the money or should you stick to the original? Will the new Switch Lite be worth the reduced price tag?

In this episode, Karen continues on in her journey to learn about logic ICs. She started with logic gates, then moved onto combination logic devices like muxes, demuxes, encoders, and decoders. This time she looks into sequential logic devices starting with flip-flops. In this episode, we learn about SR Latches, D-type flip-flops, and JK flip-flops. To understand the following devices, you may want to brush up on your logic gates. You’ll see AND, NAND, and NOR gates used to explain the function of these flip-flops. Follow along with Karen in this lesson to learn about latches, the difference between data inputs and clock signals, and what makes a JK flip-flop better than an SR flip-flop.

Spectrum analyzers display signals in the frequency domain. To use one, you only need to know about four controls: reference level, center frequency, and resolution bandwidth. In this episode, see how to use a spectrum analyzer and determine the transmitting frequency of a device.

Almost everyone will have used one, but who has ever taken one apart? Well, let's dive in together and see what it has to share

In the last lesson episode, Karen explored SR and JK flip flops. In this episode, Karen uses an SR Flip Flop with Preset and Clear to demonstrate how the inputs affect the outputs. Using that circuit and no additional parts, Karen shows how to use that flip flop to create a toggle circuit. The final project shows how the circuit can be used to create a Yes/No, Either/Or sign. This circuit is just the beginning. Adding a 555 timer or sensors instead of a button opens the door to the many different ways this circuit can be useful in an everyday item.

How does handheld gaming from 1982 compare to 2004? How different are the techniques and technologies that were both capable of holding out attention for hours at a time? What counted as "cutting edge". What have we gained, and has anything been lost?

Logic analyzers capture digital signals and then display a waveform or list. Serial busses like I2C, SPI, or UART (Serial) can be decoded or triggered on when there are problems in your circuit. In this video, learn the basic controls you need to use (almost) any logic analyzer. You’ll learn how to setup a simple trigger, make measurements, and set things like sample rate or memory depth.

The 555 timer is probably the most common and popular IC to be used in hobby circuits. There are A LOT of projects out there using the 555 in various ways and it’s easy to find schematics to make a project that has already been proven. But rather than just taking plug and playing circuits with the 555 timer, Karen wants to give you the chance to understand the why of what’s happening when you use the 555 timer. In this episode, Karen breaks down what is happening inside the 555 that makes it function. Learn how the inputs interact with the supply voltage to trigger and reset the output high and low. Find out which pins can be used to adjust the threshold at which that change happens. And see which familiar components can be found within the 555.