This article describes the theory, construction, and final project functionality of a musical circular harp that utilizes an off-the-shelf concert organ which provides 160 possible instrument sounds and full MIDI capability. Plus, it looks really neat.
What could be more fun than building a miniature oscilloscope? Not one with an LCD screen, but a scope with a real live cathode ray tube just one inch in diameter. All the parts -- including two 6AU6 vacuum tubes -- will be housed in a 5” x 7” x 2” box.
The last few years have seen a massive resurgence in the popularity and availability of voltage-controlled synthesizers. The very simple ribbon controller we’ll construct in this article will be used to control any of the myriad voltage-controlled modulation opportunities provided by the typical voltage-controlled synth.
In Part 1 of this series, I covered basic sweep alignment theory and construction/operation of an all-in-one sweep alignment instrument I dubbed the WhippleWay Sweep Alignment Board (or WSAB for short). In Part 2, I’ll describe sweep alignment procedures for AM and FM radios and give an actual example of each.
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.
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.
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.