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 project is a follow-on from my MIDI lyre project featured in the July-August magazine. I’m going to describe how to build a MIDI autoharp. Like the lyre, this is a MIDI controller, so it doesn’t make any sounds itself. Instead, it sends MIDI messages to an external synthesizer. It’s the synthesizer that makes the sounds.
Over the years with different companies I’ve worked for, I always had access to high-end audio THD (Total Harmonic Distortion) analyzers. I found these very useful for design work, debugging, and repair of audio equipment. My present company has no need for them and consequently they aren’t included in their armory of test equipment. Oftentimes, I have need for one but could never afford to own one — not even a used one. I thought this would be a worthwhile project, so this article describes how to construct one.
When you plan to create a large sign with LED dot-matrix modules, the circuits and software can seem like a big challenge. However, the step-by-step approach in this tutorial gives you what you need to know to make a sign of your own.
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.
The MIDI Replay stomp box is a powerful configuration and recording device for keyboard players, based on the wonderful MIDI protocol: the standard musical language of over 30 years.
This article explores the design challenges of this real-time system and covers topics such as task scheduling, buffers, parallel computing, dynamic memory management, response time analysis and menu system design.