Building a guitar tuner may sound complex, however doing is quite simple thanks to the simplicity of the Arduino platform and the work published by Instructables users Amanda Ghassei and "nikoala3". Their design takes the signal from the output of an electric guitar, which is passed through a small op-amp circuit to offset the waveform from AC to a 0~5V range centred around 2.5V. This allows the analogue input on the Arduino to measure the strength of the signal with accuracy.
From that point, the Arduino sketch measures the frequency of the signal which is then compared against the range of musical notes, with the result illuminated via a matching LED. The enclosure is a simple zippy box with a neat front panel design that can be easily reproduced. Overall it's a fun project that could be easily made in a day and fun to share with musically-included enthusiasts - so visit the project Instructable to find out how. And for more, we're on twitter and Google+, so follow us for news and product updates as well.