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.
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.
I use LCD displays in almost every project. However, in this modern age of steampunk, I stumbled on something much cooler — 1” high seven-segment electromechanical displays (EMDs) that go clickity, click. Here is an ambitious project that features five 1941 vintage rotary phone step-by-step (SXS) switches. These EMDs are the perfect match to display the dialed digits.
Driving LEDs using the lowest possible pin-count is a common challenge for folks creating projects with microcontrollers. Complementary LED drive, also known as “Charlieplexing”, allows a large number of LEDs to be controlled with a relatively small number of I/O pins. This fun digital LED clock project is a hands-on example of how Charlieplexing can be used to stretch your “pin budget”!
There are lots of circuits for generating high voltages out there, but what about the “gotchas?” Learn how to be safe and smart when working with these potentially dangerous types of projects.
