The Smith Chart turns the complex mathematics of transmission lines into circles and arcs that unlock the mysteries of SWR, stubs, matching networks, and a whole lot more. It’s an amazing tool that brings the arcane math of transmission lines to visual life so you can understand them.
Even though CW is no longer a required component of amateur radio license tests, it’s still a practical and fun skill to learn. Plus, these days, there are many different learning aids readily available. All you need is the discipline to spend 10-20 minutes/day practicing and you’ll be sending and receiving CW before you know it.
The whole Internet of Things (IoT) phenomenon has been around for a while now. But have you tried to create an IoT device on your own? If so, you know it’s not easy. However, it is now easier than ever as many of the manufacturers of IoT wireless chips and modules are providing the hardware and software to make an IoT device happen with minimum work. One example is the Wireless Xpress BGX13P module starter kit from Silicon Laboratories.
Having read about the ESP8266 NTP clock in previous issues of Nuts & Volts, an idea came to mind to construct an interface camera using the ESP8266. In this project, we used an old Android phone as a camera source and linked to an ESP8266 based webserver. The phone acts as a camera server and the ESP8266 web server acts as a client to the camera server. The webserver displays the live webcam on its web page.
In my experience, few hobbyists or experimenters take advantage of C preprocessor operations. You've probably seen preprocessor directives such as #include <stdio.h> or #include "servo.h"among the first lines in programs. However, they are not part of the C language. When you compile a program, it first goes through a preprocessor that handles housekeeping tasks such as including files that operate a peripheral or that provide a function such as printf. This tutorial will show you how to take advantage of this.
Here are a few of the many possible variations on the general theme of discrete-logic digital clocks. If you have a few LED displays, counters, drivers, and simple logic, you can probably build a clock. Consult the datasheets of the ICs you choose to use, breadboard everything first, and have fun.
When the concept of electromagnetic waves was first proposed around 1864, it was met with great skepticism. As a result, the idea languished for a long time. It took several decades for a handful of dedicated persons — infatuated with the mysteries of electricity and magnetism — to finally put the theory on a solid footing.
The February and March 2018 editions of Nuts & Volts featured my article detailing the Arduino Graphics Interface (AGI) project which described a general-purpose hardware and software platform that could draw graphical objects onto the face of any analog oscilloscope. A reader challenged me to see if the AGI concept and software library could be ported to the newer and faster TEENSY 3.6 processor. This article describes the new and improved TEENSY Graphics Interface project that implements a fully operational “CRT Clock” as a working demonstration of a TEENSY based graphics platform.
This November, in Versailles, France, representatives from 57 countries are expected to make history. They will vote to dramatically transform the international system that underpins global science and trade. This single action will finally realize scientists’ 150 year dream of a measurement system based entirely on fundamental properties of nature. The International System of Units — informally known as the metric system — will change in a way that is more profound than anything since its establishment following the French Revolution.
Sometimes I wonder which of my portable digital voltmeters I can trust — the B&K, Fluke, or Amprobe. Usually, they’re pretty close but it bugs me not knowing whether they are right on the nose. Fortunately, these days, there are a number of very accurate voltage reference circuits that you can build or purchase for a few dollars.
