Build a Digital Audio SPDIF Output for Your Computer, Laptop, Tablet or Phone

Even though today's computers, tablets and smartphones are capable of producing ultra high-quality digital audio, it's left to cheap digital-to-analog converters (DACs) to transform it into sound. Those who listen all day to a low-bitrate MP3 stream on a cheap plastic mono bass-boosted Bluetooth loudspeaker probably don't care, but there are people who are willing to invest time and money in quality audio. A good step in this direction is this USB-to-SPDIF interface that allows our digital sources to connect to high-end AV receivers, stereo amplifiers or stand-alone audio DACs. It even features IR remote control.

All over the world people are launching solidarity projects to help others through this difficult period. Some have started to prepare and deliver food to hospitals, others make masks; there are companies that have repurposed (part of) their production facilities to make hydroalcoholic gel or spare parts for respiratory equipment. If you read this, then you probably have maker skills, tools and the creativity to come up with practical solutions for problems. Elektor Labs is still up and running, and even though we do not have production facilities, we do have a website for posting projects, and we have contacts all over the world. We know engineers and makers; we know big technology companies and bright young start-ups. We can help with connecting people, finding solutions, technical advice, and production and distribution facilities. Whatever you do or come up with may help someone else. Therefore, keep on making!

Many of us have at least bought one of those cheap remote-controllable 433-MHz ISM band power plug kits available for little money from gadget stores everywhere (I own two). You may even have used it (I didn't). They plug into a normal power outlet and come with a small remote control. Even though they make our lazy lives a little lazier, they could be much better at this if only they were programmable. This project adds just that.

It is instructive, easy and even fun to play around with the free circuit simulator LTSpice every once in a while. In this video you will first learn how to analyse and understand a simple opamp-based square wave oscillator taken from an “old” datasheet before changing it into a voltage-controlled oscillator (VCO). Building the circuit on a breadboard shows that it really works. The simulations are of course available for downloading to get your own experiments up and running quickly.

An RF Power Meter for measurements up to 10 GHz was published in the March & April 2018 edition of Elektor Magazine. The project turned out to be very successful so the author went about improving his device. The version he is currently working on will be compatible with almost all power detector chips available on the market, it will have two channels and a dynamic range of 92 dB. Add to that a touchscreen, Wi-Fi and Bluetooth and you end up with a close to professional measurement tool.

One reason to play around with electronics is simply for the fun of it. For instance, you can build devices for making noise and producing sound effects. The fun project presented here is about building a police-style blue and red flashing light. Not a simple light with a blue and a red LED, no, this one has 36 LEDs of each colour. And it is not Arduino-compatible but uses an STM8S001J3 8-bit microcontroller instead.

Intrusion detection and automatic garage door openers are just two examples of applications that commonly use infrared (IR) beam detectors. When the device is to cover more than a couple of meters, sensitivity becomes an issue. This project, built around a standard 38-kHz IR receiver module (like the one found in television set) and a bunch of NE555 timer chips, easily covers distances of up to seven meters.

Watching a rolling or scrolling message display a.k.a news ticker is as captivating as TV. Even after having read all the text twenty times or more, no matter how uninteresting, you just keep watching it. Often such displays are monochrome, red is very common, but with those cheap WS2811-type addressable RGB LEDs it is easy to make a full-colour ticker. Here's how.

Even though thousands of designs for all sorts of timers have been published over the years and commercially available timers exist in uncountable flavours, yet there seems always room for one more that somehow fills a gap or a particular need. The timer presented here excels in not having a display, and that on two channels.

Microscopic particles of solid or liquid matter suspended in the air impact human health through climate changes and direct inhalation. Also known as particulate matter (PM) the fine dust particles are commonly classified by size. PM10 designates particles with a diameter from 2.5 to 10 μm; PM2.5 is the category of fine particles with a diameter of 2.5 μm or less. PM2.5 pollution is considered particularly deadly as it can cause lung cancer. Did we scare you? Then this project is for you.