The last time I had my hearing aids serviced, I discovered that the devices included a T-mode operational feature. The T-mode (or Telecoil) setting allows you to receive audio signals fed to an induction loop, which is just a wire loop laid on the floor around the perimeter of the desired area. Induction loops can be found in places such as concert halls, movie theaters, auditoriums, churches, banks, and public buildings where PA announcements are common. I decided to build an installation for my home. Here’s how it went.
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.
With "smart" cell phones, Wi-Fi, RFID tag systems, and so many other new applications for radio waves these days, it is obvious that we are immersed in an electromagnetic field ("EMF") just about everywhere we go. Here's a circuit to experiment with collecting and measuring the energy present in our environment.
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.
Small Geiger-Müller (G-M) tubes make ideal sensors for pocket-sized devices to detect radioactivity. However, even a small G-M tube needs an anode voltage in the 400 to 600 volt region. Here's how to generate that voltage from a 9 V battery.
An open garage door is an invitation for thieves and vandals. And don’t forget the mischief birds, cats, raccoons, and other animals can cause in your garage. No problem! This handy device will close it automatically for you.
This time, we'll build two projects. The first is a transformerless voltage doubler that takes a DC voltage from 12 to 30 volts and doubles it. Unlike most other voltage doubler circuits, this design can supply amps of current. The second project uses a power MOSFET in a linear (rather than switching) application.