One shot at stardom

[Mark Hammer]

So about a year ago, I contacted Tom "Electric Druid" Wiltshire, and we began a discussion about him possibly producing a "one-shot" event generator.  That is, in contrast to a typical LFO that stays on all the time, this would be something actuated by a momentary switch, complete its task, and then get out of the way.  Part of my impetus was an idea I had for a complex modulation source that might have changing patterns which could be initiated on demand.  So, for example, imagine an LFO that could be made to sweep progressively faster up to some maximum then return to normal sweep speed, and all you had to do was hit a stompswitch whenever you wanted it.

I guess the idea intrigued Tom enough that he embarked on the mission and came up with an 8-pin wonder that would do just that...at least the one-shot. ( https://electricdruid.net/one-shot-event-generator/ )  He sent me some samples, but it took me a while to get around to making use.  One is reserved for a combined modulation source in tandem with the StompLFO that I'm working on.  But after 11 months of waiting, I finally got around to making use of the other one, and built it into a little 1590A box, with a soft-touch switch and mini phone-jacks for feeding a CV out and taking an external trigger source in.  Tom's website shows the parameters available for the unit.  It can be used to generate a single cycle of 8 different waveforms, but can also generate a given number of repeats of that wave, with variable spacing between each repeat.

I whipped up a little patch cable to make use of the expression/CV input on my Chase Bliss pedals, and started dickering around.  Hopefully, I can whip up a demo over the next few days, with some striking examples of it in action, but so far it is interesting and gets some sounds you couldn't necessarily make with your foot or a conventional LFO.  I'll have to comb through the pile of pedals in the basement and see if there are any others with CV/expression-pedal input that can be tinkered with.

The point is that it's a chip well worth exploring as a different kind of modulation source.
Thanks, Tom.  Much appreciated.

[EBK]

Thought from the subject line that you were going to somehow try to tell us that you weren't yet famous. 

[Mark Hammer]

Nah.  It was the only coy phrase I could think of that used the term "one-shot".

[toneman]

so.........

...sort of like the equivalent of a programmable 555???   

errrr....almost like the equivalent of TWO programmable 555's 
(because of the "sweep" function)

In an 8pin package

David Gilmore and the Synthi HiFli guys would be proud   



....then....
...I found this:
https://hackaday.com/2015/05/06/a-simple-programmable-555/


I got to stop googling ing ing
https://hackaday.com/2013/02/08/programming-a-555-chip/

[bluebunny]

Thought from the subject line that you were going to somehow try to tell us that you weren't yet famous. 

I thought Mark was going to announce he's got through the audition rounds for "Canada's Got Talent".   

[Ben N]

[Mark Hammer]

Thought from the subject line that you were going to somehow try to tell us that you weren't yet famous. 

I thought Mark was going to announce he's got through the audition rounds for "Canada's Got Talent".   

I think it's more like "Canada's got talent....somewhere....no, that's not it....just a sec, let me look, maybe it's in that drawer....no, that's not it either....I'll get back to you".

[Ripthorn]

I'm doing something related, but not quite the same, for a project I'm working on now. I will be using a 6 position rotary selector to select one of 6 predefined patterns, along with the ability to do a manual mode and a continuous mode, all with tap tempo. I have the code written and programmed to an ATTiny, but I still need to build up the rest of the circuit on the breadboard and fine tune. Should be fun!

[Mark Hammer]

Neat!  I look forward to the finished product.  I have tremendous respect for those who can dive right into micro-controllers and make them do tricks.

[Mark Hammer]

Here's a quick and dirty demo of the controller box feeding the CV input of a Chase Bliss Condor.  I don't have much of a video setup, so I have to wear the camera on my head, keep my view on the computer screen to make sure everything remains in frame, hit a chord, and press the momentary switch to initiate the CV output.  I used the schematic found in the One-shot datasheet.  I'm using the log up sweep, and controlling the cutoff filter of a 2-pole resonant lowpass, as well as the centre-frequency of the midrange boost.  The fuzz is some 2-transistor one-knob DIY schematic whose provenance I completely forget.  I added a 3-way tone switch, and 3-way clipping switch, because I couldn't stand to see all that empty panel space.

I also tinkered around with the box driving a Chase Bliss Spectre flanger, and the modulation bus of a Boss RPH-10 phaser, though I didn't capture any video of that.  Maybe tomorrow.  The RPH-10 had been modded to have envelope controlled sweep, so I turned the Depth down fully to make it an envelope-only sweep, and the one-shot box can provide modulation-on-demand on top of the envelope-control.

Long story short, the chip, and controller, show promise.

[antonis]

after 11 months of waiting,

334(5)  X :

[garcho]

bravo, i can think of many uses for this

[GGBB]

I think it's more like "Canada's got talent....somewhere....no, that's not it....just a sec, let me look, maybe it's in that drawer....no, that's not it either....I'll get back to you".

"... oh right - they all went south of the border."

[KarenColumbo]

I'm always inclined to write off humanity as a crying failure. This forum proves me wrong every time

[Ben N]

Personally, I prefer to think of myself as a laughing failure.

[ElectricDruid]

Very nice, Mark!

I like the little box with just the One Shot gizmo inside it. Incidentally, the pin-out is exactly the same as the StompLFO that it was derived from, so if you've got a PCB, you could do another one with a StompLFO. Or just swap the chips over in the one you've got.

I also like the modular-synth-inspired patchability of it. My own pedals have been going in a similar direction, especially the FilterFX, which includes both a Sync input to sync the internal LFO, and also an expression pedal/CV input. Great fun when sync'ed up to a synth sequence from somewhere.

BTW, I really must reply to your other email about another pesky idea...

Tom

[garcho]

BTW, I really must reply to your other email about another pesky idea...

you must indeed!