Thrill everyone by at long last getting your instrument properly tuned!

“If music be the food of love, play on,” proclaimed the Bard. Fine sentiments indeed, but only justified if the music's well tuned and on beat! This PIC-based design can help you ensure that your serenades at least start off with the correct notes - even if you do then play them in the wrong order.

The PIC microcontroller accurately generates the initial seven natural notes of an octave, A to G, any of which can be selected via a switch, as can one of two octaves, commencing at 220Hz or 440Hz. It can output the selected tone to headphones or a speaker, at a panel-controlled level.

It also compares its own tone with the frequency of an acoustically or electrically input note, and indicates via an l.e.d. (light emitting diode) how closely the two signals match. Lots of flashing and you're way off - no flashing and you're spot-on (or the battery's dead!).

A metronome mode can be selected in place of the tuning fork, and it outputs a “click-track” which can be set for different time signatures with an accented down beat.

This design originated at about the same time as the author's StyloPIC (July '02). Its software generated tuning principles are based on the same additive technique as that design, in which fractions as well as integers are used to set the frequency. This allows greater tuning precision to be achieved than is possible with the more conventional integer-only additive techniques. (The principle is discussed at greater length in the StyloPIC article.)