Source code for my Arduino Digital Audio Recorder

One of the most popular (and one of the trickiest) Arduino projects I’ve designed so far is the Arduino Digital Audio Recorder. It appeared in APC magazine issues #403 and #404. It turned an ordinary Arduino Uno R3 microcontroller board into a WAV format audio recorder that can capture 8-bit audio at up to 48kHz and store it on a FAT-formatted microSD card.
I’ve made use of and want to thank the authors of the sdfatlib library, which makes the FAT filesystem possible on an… Read more

Build your own Bluetooth speaker setup for under $5

Bluetooth speakers are pretty popular at the moment – well, at least there seems to be plenty of them around and plenty of brands out there flogging their socks off.
But if you read more than few of the reviews, there’s a decent proportion not worth your time, with common complaints being tinny sound/not enough bass.
That’s not surprising, given in many cases, they’re little more than battery-powered audio amps driving tiny speakers no more than two-inches/five-centimetres at most, with… Read more

Build your own Digital Audio Recorder from #arduino

The first part of my Digital Audio Recorder project has just hit the APC mag website.
I had heaps of fun putting this project together – and now you can do it yourself. The story includes all you need to know to build it, including the software that turns the Arduino Uno into a digital recorder.
The project records analog audio via a 3.5mm stereo panel socket to a MicroSD card in WAV format, playable on any WAV-compatible device or… Read more

[ARDUINO PROJECT] Build a stereo peak program meter with #arduino

My Arduino Masterclass story on how to build a Stereo Peak Program Meter has just gone up on the APC magazine website.
Peak Program Meters (PPMs) have essentially replaced the old VU meter in audio recording, thanks largely to the shift to digital recording. A PPM measures logarithmic voltage changes but in a linear display. Specifically, my project uses an Arduino Nano to show a stereo analog audio input on two banks of ten LEDs. The trick here is that you… Read more

6V6 audio valve turns a spritely 75 years old

Many of the best guitar amps, including many of the early Fender models like the Champ, use thermionic tubes or ‘valves’.
The Champ itself runs a 6V6 output tetrode valve, which appear in late 1937.
And you can still buy these valves today, which isn’t bad for a technology that’s 75 years old. Not too many technologies last that long.… Read more