Dr.Godfried-Willem RAES

Kursus Experimentele Muziek: Boekdeel 2: Live electronics

Hogeschool Gent : Departement Muziek & Drama

<Terug naar inhoudstafel kursus> METRONOME Dit hoofdstukje is niet beschikbaar in het nederlands.


Some time ago we were asked to design a metronome wherewith the tempo could be adjusted in equal tempered semitone steps (2^(1/12)) instead of the usual divisions "Lento- presto" and their MM (Maelzel Metronome) equivalents. Of course such a task would be easy to accomplish using <GMT> on a Wintel PC. Such a solution could however never compete with the compactness of commercial metronome devices. Hence our recourse to the infamous PIC controllers programmable in Basic from Parallax Inc.

We used a basic Stamp (a BS2 type from Parallax) to implement this with just a few components and, of course, some software:

This is the circuit:

Twelve I/O pins (0-11) are used to select the semitone for the tempo (a 12 position rotary switch came in very handy here), and 2 bits are used to set the octave (12,13). Here also we could have used a rotary switch, but we finaly did put two toggle switches. We provided 2 octaves for a range rquivalent to MM=30 up to MM=240. So the tempo corresponding to 'C' with the octave switch set to down, will be exactly MM30. The octave up is then 60 and one higher 120. Using the last free pin, it could be expanded to an extra octave easily.. The output is a single LED connected to I/O pin 15. For an audible output, you can replace the LED with a small piezobuzzer. If you want a loud click, use a PNP transistor driver and a small loudspeaker. Current output of the stamp is limited!

And the software, as you should download it once into the PIC controller looks like:

'* Chromatic Metronome *
'* by *
'* Dr.Godfried-Willem RAES *
'* Stamp2 Hardware version 1.0 *
'* Filename : Metronoom_BS2.BS2 *
'* Code version 1.0 *
'* commisioned by Marc Maes *

Finished metronomes can be obtained from the Logos Foundation Labs on request. Price is around 100 Euro.

Filedate: 2001-07-21 last update: 2004-04-19

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