WIRESPONDENCE!

Recording a message on a wire spool and mailing it off to family and friends became a growing fad called “wirespondence.”

The magnetic wire recorder, ancestor to the tape recorder, had undergone great development during World War II. By the late 1940s, wire recorders were available in consumer equipment.

USING SERIAL BLUETOOTH WITH A MICROCONTROLLER

Stream serial data via Bluetooth as an alternative to RS-232 cables and build a Crystal Palace in the process.

In my previous article, I developed microcontroller-based hardware and software to control a matrix of 8×8 RGB LEDs. I thought since I still had that hardware laying around, I would use it as a test bed for experimenting with Bluetooth. I had never done anything with Bluetooth before, so I thought it was about time I did.

WHY YOU NEED AN ANALOG FRONT END AND HOW TO SET IT UP

How to make your sensors talk nice to your microcontroller.

The analog input to an Arduino Uno has a resolution of only 10 bits. On a 5V scale, this is only about 1 mV of sensitivity. If you need more sensitivity, don’t look at another microcontroller. Look at adding an analog front end to your Arduino.

RESTORING A VINTAGE ZENITH TABLE TOP AM/FM RECEIVER FROM THE ’60s

Explore the world of tube-type electronics by restoring a classic AM/FM receiver.

Teardowns of vintage gear in which you carefully note component values, construction techniques, and create a schematic from scratch are a great introduction to vacuum tubes. The next level (and the focus of this article) is to restore tube-type devices, starting with a tabletop radio. Not only will you learn to work with the technology, but you’ll have something of value when you’re done.

Two YouTube Channels — One Common Purpose

Using the power of simultaneous livestream on both their YouTube channels, two amateur radio operators are raising public awareness on behalf of a Detroit area ham who has been diagnosed with end stage renal failure. Phil Ross has been told that unless a matching kidney can be located from a living donor soon, he will require dialysis, a time-consuming intervention that is not considered a cure.

Christian Cudnik and Alexander Valladares are turning their respective channels on YouTube into venues for the “Papa Phil Challenge” in the hopes a compatible donor can be found in time.

Cudnik’s YouTube Channel, 100 Watts and a Wire, presents a weekly amateur radio talk show that reflects on the intersection of life and ham radio. Mr. Valladares’ YouTube Channel, W7HU Alex, livestreams the amateur radio contacts he makes — many of them international — from 3 p.m. to 6 p.m. on weekdays.

After much discussion on ways to get the word out to the public on the immediacy of Phil’s health crisis, Cudnik in MO and Valladares in Florida realized they had just the right tools. “I started sharing ideas on how to help ‘Papa Phil’ find a living kidney donor,” said Cudnik, “and that is how this campaign came to fruition.” Cudnik calls his weekly Wednesday program “The Spirit of Radio,” a nod to the prominent role ham radio plays in public service.

Valladares said: “The only thing we ask in return is those who watch our live streams post the link to Papa Phil’s video from his website on their social media pages.” For more information, please visit the “Papa Phil” website at http://www.papaphilcan.com.

Meanwhile, amateur radio operators around the country are joining Cudnik and Valladares to further amplify the urgent need facing the Michigan grandfather by getting on the shortwave bands allocated for ham radio and sharing Phil’s story. The activity known as Special Event Station K4P will take place from March 13 to March 20.

To schedule an interview contact:

Bob Mente NU3Q

412-736-7385 • nu3q

GENERATING ANALOG WAVES FROM DIGITAL SIGNALS

Getting good analog signals out of digital ones can be done fairly easily with a minimum of parts.

It does take some programming effort, and high-frequency audio signals require most of the uC clock cycles. However, if you experiment with these two general approaches you will probably find some interesting applications for your projects.

BUILD A DIY ELECTRIC SCOOTER

Here’s how I designed my only electric scooter from scratch.

With the influx of electric skateboards and scooters that have taken over seemingly every city, I started thinking it might be something to purchase for myself. Instead, I decided that I would try to build my own from scratch. Not really to save money, but to gain the experience of building something of my own. The primary purpose of this article is to show my design and manufacturing process, so that you can learn from what I built.

THE SOLAR ALTERNATIVE

A solar cell (sometimes called a photovoltaic cell) is basically a large diode. Just as a photodiode (or even, for that matter, a regular glass-walled diode like a 1N914) will produce a voltage when exposed to light, so will a solar cell.

Efforts to design and construct devices for supplying renewable energy surprisingly began many, many years ago, ironically, at the very height of the Industrial Revolution which was largely founded on the promise of seemingly inexhaustible supplies of fossil fuels. Contrary to the prevailing opinion of the day, a number of engineers questioned the practice of an industrial economy based on nonrenewable energy and worried about what the world’s nations would do after exhausting the fuel supply.

DRIVING LEDs WITH A MICROCONTROLLER

Do more stuff with microcontrollers than just blinking LEDs.

Typically, one of the first experiments people do when working with microcontrollers is to blink an LED. However, the thrill of this wears out pretty quickly, so let’s see what else can be done.

THE CARE AND FEEDING OF ANALOG METERS

In a digital world, there are still quite a few uses for an analog meter, but these beasts require special TLC.

Though just about every experimenter will likely have digital meters on their benches, many do still keep an analog meter around since there are some jobs where these devices can perform better than their digital counterparts. Keeping these analog devices in good repair requires a bit of care.

THE LOST ART OF STRIP BOARD PROTOTYPING

Use this timeless technique to wire up circuits for prototyping or functional applications.

Many techs of yesteryear built their projects on a breadboard, then would transfer everything to a mirror copper clad board. Here’s everything you need to know to use this timeless technique.

COMPILED BASIC FOR THE PIC ON A SHOESTRING

Free yourself from Assembler and learn how to set up a complete integrated environment for writing, compiling, and burning Basic programs into just about any PIC — for “basically” free.

Whether you’re a PICAXE aficionado who longs to progress to faster programs or are already a PIC devotee who wants something easier than assembler language to work with, here’s just the ticket.

DIY BIOTECH: GENETIC ENGINEERING WITH THE DNA PLAYGROUND

Modify E. coli bacteria to produce proteins of your choice.

Explore how you can modify E. coli bacteria to produce proteins of your choice; that is, genetic engineering: the direct manipulation of an organism’s genes using biotechnology. We’ll also review and tear down the DNA Playground: an affordable all-in-one hardware platform that’s simple enough for middle-school students to use to genetically engineer bacteria.

RADAR AND ELECTRONIC WARFARE FUNDAMENTALS

Fundamental concepts of radar and how EW (Electronic Warfare) develops.

Radar and Electronic Warfare are usually thought of as being very complicated and very secret. While this is true for specific designs and detailed theory, many of the basic principles are straightforward and easy to understand. This article will present some of the fundamental concepts of radar and show how EW develops from that.

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BUILD A POTENTIOMETER BOX

Now that I’ve built my potentiometer box for analog experimentation, my only regret is I didn’t do it sooner.

Now that I’ve retired, I’ve started experimenting with some of the analog subjects that I haven’t done much with since school back in the seventies. To begin with, I started with op-amp circuits; specifically, Colpitts oscillators. I built the circuit on one of those plug-in ‘protoboards,’ a ±15V power supply, an oscilloscope, and a multimeter. For my experimentation, I was using a trim pot. I would adjust until oscillation began, then power down, pull one end of the trim pot, measure the resistance, then re-connect, power up again, and continue adjusting until I reached the other end of the resistance range, where the oscillation would cease. I would then repeat the resistance measurement. That procedure was not ideal. In addition to the multiple tedious steps, adjusting a trim pot can be a pain. Enter my potentiometer box.

THE ZOMBIE APOCALYPSE — ARE YOU READY?

How prepared are you for a disaster — man-made or otherwise?

The power grid is down, there is no Internet, no cellular, and no landline communications, and killer zombies are on the loose. Or, maybe it’s a hurricane, tornado, or earthquake. Is that any better? Could you make do? Could you leverage your skills in electronics to call for help, cook and preserve your food, and provide light? If you’re not sure, get some practice by participating in the ARRL Field Day.

BUILD THE NIXIESTAR CLOCK

Construct this elegant and intricate timepiece.

The NixieStar clock is the second timepiece kit I’ve developed. My aim was to have a kit that’s reasonably easy to build with intermediate soldering skills (i.e., minimal SMD components). I also wanted a clock kit that once it was built, any spouse (including my wife!) would accept it on their wall — even with a power cord hanging from it.

THE ‘OPTO’ IN OPTOELECTRONICS — PART 4

The basic operating principles of LEDs and lasers are covered in this final episode of the series.

This final episode describes the basic (atomic level) operating principles of LEDs and lasers, with particular emphasis on modern laser diodes.

PROBING CORES

Build an oscilloscope accessory that displays the B-H curves of inductor cores.

Some time ago, I built a handy self-contained inductance meter (What the L is it?). It works well, but it registered nothing when I tested some inductors I’d picked up at a hamfest. I set up my old standby — a parallel capacitor, a signal generator, and an oscilloscope — and found these inductors were extremely lossy. As their cores were wound from metal tape, I wondered if they were designed to have square-loop characteristics. I put together a device to display their behavior. Here it is.

BUILD THE MUSIC VISUALIZER

An interactive LED display that reacts to music.

As a final class project for our “Digital Systems Design Using Microcontrollers” course we all took last semester at Cornell University, we created a very unique device. We wanted to design something fun, aesthetically pleasing, and interactive, and since we all enjoy listening to music, we decided on a music visualizer. Our vision was to create a unit that listens to music being played, then in real time displays a dynamic and colorful visual representation of the music based on the volume and pitch of the notes. Additionally, our music visualizer provides an alternate avenue for experiencing music for the hearing impaired. Here’s how we did it, so you can make one too!

THE JOYS OF RETOOLING — AGAIN

Is retooling your shop and your mind to the world of vacuum tubes worth it?

If you’re contemplating expanding your knowledge base — or revisiting your past — as it relates to vacuum tubes, should you invest in a new infrastructure or stay the course? Well, there’s certainly more for anyone to learn about the ever-expanding world of microcontrollers, drones, and the like. However, there’s just something magical surrounding a simple tube device.