[sdiy] Simple MIDI-syncable LFO...?

[Blandon Ray]

On Mon, 18 Oct 2004 10:50:11 +0200, Fredrik Carlqvist <ifrc at iar.se> wrote:
> 
> Why not make a regular analog LFO that is reset every NNth MIDI clock
> message? Keep the LFO rate knob and use it to adjust the waveform. The WASP
> LFO is very simple and has at least 4 different waveform outputs.

Thanks everyone... I found a few schematics on the Web that gave the
the impression that this could be done, for example, this one:
http://www.musicfromouterspace.com/analogsynth/coolnewlfo.html

(is this from someone on the list?)

It looks to me (novice that I am) like that circuit is essentially
producing other waveforms from a square wave derived from a
comparator, which is essentially what I want to do. Blacet does indeed
have the CMOS divide circuit published, and since I wanted some other
stuff from them I went ahead and ordered a PIC as well, so it's time
to do some breadboarding. I'll probably take the time to learn
microcontrollers eventually, so as Red Green would say, this is only
temporary... unless it works.

Incidentally, as someone else pointed out, control of phase is VERY
important for this application. I bought one of those Electrix effects
units that has MIDI-syncable tremolo, delay, and a few other things,
but in that unit, the phase of the LFO is reversed (it is in the
negative half of its cycle on the beat). Of course, that makes it much
less useful from a musical point of view.

Blandon