Everything for Electronics


Designing a Programmable DC-to-DC Converter

DC-to-DC (DC-DC) converters are a common part of modern electronics. The need for an “odd” voltage can arise for biasing, backlighting, analog components, communications, or — as in the case of the LP130 discussed in the last issue — programming and verification. If your main circuit is powered from +5V and you have a few chips that need 3.3V, a simple linear regulator will suffice. However, linear regulators can only reduce the supplied voltage. Most practical DC-DC converters are a type of switching regulator and in this article, DC-DC converter means a switching type of regulator.

Build a Simple Isolator for Externally Powered Arduinos

Arduino Unos and Megas are normally powered by five volts through their USB connectors or by connecting 7-12 volts to the power jacks or Vin header pins. However, there is another way. This is a very simple project, but it sure makes programming easier.

Build a Vintage Radio Sweep Alignment Instrument

The popularity of repairing and restoring tube radios has highlighted the need for a variety of test instruments. After repair or restoration of a radio, the final step is often alignment. For an AM radio, a signal generator and voltmeter will do a good job. But with an FM radio, using a signal generator and voltmeter does not always produce the best results. So, I came up with my own design using a digital signal generator module, Arduino processor, and digital display.

Build a PICBall Machine

For our “Designing With Microcontrollers” class at Cornell University, we built a pinball machine with electronic components controlled by software on a PIC32 microcontroller. This article details the design process, challenges we experienced, and solutions we came up with while completing the project from start to finish.

Build a Digital Clock Family Using Nextion Displays

I’m a digital clock nut. I began experimenting with the newer Nextion displays, which I really like. I’ve produced digital clock versions for the 3.5, 5, and 7 inch size Nextion display. They all run from the same printed circuit board and have several different functions.

Build a Marquee Style Lighting Controller

When I was in university, a local restaurant owner approached me about designing a marquee lighting system in his entrance stairwell. He wanted to attract and guide more customers to his business. He never did agree to the proposed price, but it planted a seed. Since that time, I have seen many marquee-based systems at places like local theaters or animated holiday displays. So, I set out to design my own system.

Build an Inexpensive Magnetometer

This article describes a Hall-effect based magnetometer that uses an inexpensive analog Hall-effect sensor, an Arduino, and LCD. The linearity of the magnetometer is surprisingly good when compared against a commercial magnetometer. This unit can be operated manually or make measurements under computer control, so we’ll use our magnetometer in a computer-controlled setup to measure the BH-curve of small sample of magnetic material.

Build a Ham Radio Voice Keyer for the Backpack

Could I get by with fewer amenities and shrink the size, weight, and power requirements of my keyer to make it more portable when going on a mini-DXpedition? It was worth an investigation.

The Electric Brains of Yesteryear

In the 1950s and ‘60s, Popular Electronics and other magazines carried ads for strange looking machines called Geniacs and Brainiacs. The ads claimed they were “electric brains” that could play Tic-Tac-Toe and NIM. A while ago, I bought several sets on eBay and I would like to share my experiences of learning about them and my sometimes frustrating — but successful — efforts to get them to work.

Take the Z80 Challenge

This project started out as a challenge to myself: Could I cram a full-featured Z80 microcomputer using DIP packages onto an ExpressPCB MiniBoard (3.8” by 2.5”)? Here’s what happened.