Stepping Stone schematic.

[bobbletrox]

I finally got around to drawing up a complete sequencer + pwm combo that corrects some of the errors in the diagram I posted for R.G.'s sequencer back in July.

Some differences between the one I perfed and the new diagram are:
* I used seperate 40106s for the PWM and clock, but it can be done with one
* I used a rail splitter chip dealie for the bias voltage on my perf
* I accidently used a 22uF cap for C4 when it should have been 2.2uF
* I didn't try the switch that disconnects the sequencer from the "manual" pulse width pot.

So all the fixes in this diagram should make it better than the one I built hopefully!  It'd probably fit into a BB sized box if you use 9mm pots.

Stepping Stone:
http://users.bigpond.net.au/styrowfoam/steppingstone.gif

Plain Sequencer:
http://users.bigpond.net.au/styrowfoam/sequencer.gif

[jrc4558]

What it does? Just curious...

[bobbletrox]

8 Sequence knobs: can be set to anything from a fat square wave to a nasal tone (or even silence)
"Speed" knob: controls how fast the sequencer cycles through the 8 knobs
"Manual" knob: controls the overall range of the 8 steps
The switch: disconnects the sequencer and lets you manually set the pulse width with the "manual" knob

If that makes sense :shock:

Here's an old sound sample from when I was still having problems with it:
http://users.bigpond.net.au/styrowfoam/sequenced-pwm.mp3

Keep in mind that only 4 steps out of 8 were working at that point!  The finished version has all 8 working.  That's also played through a slightly overdriven amp to accentuate the changing pulse width.

The addition of LEDs to follow the sequence and the ability to start the sequence when the pedal is activated would be handy, but I'm not really sure  if it's possible with this sequencer.

[petemoore]

Very interesting stuff Bobbletrox !!!

[bobbletrox]

I whipped up a quick pcb layout that may be able to be shoe-horned into a b-sized box, or if not, definitely a bb-sized box with enough room left over for a 9 hole golf course.  I didn't hear any clicking from this circuit, so I hope packing it all so tightly won't make a difference.

http://users.bigpond.net.au/styrowfoam/steppingstone.pcb

The only things that may need tweaking -if at all- are the values of C4 & R4.  My clock speed went from lightspeed to slow motion because of the 22uF cap I accidently used, but hopefully the new values should fix it.  I'd already canibalised the test perfboard before I'd realised my mistake.