Everything for Electronics


Turn Your Computer’s Sound Card into a Scope

The oscilloscope is my go-to measurement instrument in every electronics project I work on, helping me debug and fine-tune hardware and software projects. In this article, I’ll show how you can get started with a simple-to-use scope you probably already have. Best of all, it’s free! When you graduate from this simple scope, you can purchase a more powerful scope using the exact same user interface. I think the free scope control software, Waveforms, is the simplest to use, most feature-rich pro-level software of any of the available options. Using a sound card as the hardware interface with Waveforms puts a simple yet powerful scope in your hands for free.

Build a Configurable Clock/Timer

This project implements a clock/timer device with several handy features other than just a simple alarm. It utilizes a 16-bit PIC, the MPLab Code Configurator, and a serial LCD.

Build a 3D Printer Filament Scale

One thing you want to check before you start a long 3D print job is to verify you have enough filament on the spool to complete the print. You don’t want to come back to your printer at the end of a two-day run (as I have!) only to discover that the machine ran out of filament and the top part of the object is missing! This project describes a dedicated “spool scale” that provides a real time readout via an Arduino of just how much material you have left.

Four-Position HF Antenna Switch with PC Control

Meet the SW-4U: A four-position ham radio antenna switch with PC control via a USB connection. The switch is controlled by an application program running on the PC that allows you to select any of four antennas, ground all for safety, and to power the switch on and off.

Build a Headphone Amplifier — Times 3!

There are situations where a low output impedance to A headphones is required. This article discusses three different versions of headphone amps to fit your particular application: a stereo amp powered by the power line; a battery-operated mono amp for a crystal set; and a battery-operated amp for a ceramic cartridge.

AC Volt/Amp Meter with Web Interface

Work areas usually have multiple power strips ganged together and connected to the same outlet. Various devices are connected to these strips, including computers, lights, coffee pots, space heaters, etc. Environmentally conscious persons ask, “How much power does my work area consume?” Safety conscious persons ask, “Am I overloading my circuit?” Calculating the answers requires two basic measurements: the voltage supplied to the circuit, and the amperage consumed by the circuit. Measuring AC voltage and, particularly, amperage with a multimeter is a potentially dangerous diagnostic for laypersons.

Wouldn’t it be nice to have a self-contained volt/amp meter that displays the values on a webpage?

Restoring the Heathkit ES-400 Computer

It took me eight months of part-time work to restore all 168 pounds of a Heathkit “H-1.” I would like to share a few of the trials and tribulations I went through to resurrect this beast.

Monitor Motion from a USB Webcam

This system monitors motion from a USB webcam on a Raspberry Pi 3 using the OpenCV API. Once movement is detected by the system, it takes a picture of what set the motion detection software off and emails that picture to you. It also affords you the ability to remotely view the webcam from an Android application from anywhere in the world at any time.

Build a Small Powerful Dummy Load

A dummy load is a resistor used to load any radio frequency generator/amplifier to simulate an antenna for testing purposes. It’s used to allow full power output while testing or experimenting without radiating a radio frequency signal. Here’s one you can build for less than $5.

Build a Digital Light Saber

Want to “paint with light?” This article explains in detail how you can build a low cost (<$100) microprocessor-controlled LED light saber that provides as much or more capabilities than professional light wands.