Drew’s Toaster

At Vitamin one of the movers and shakers is a man named Drew who has the misfortune of being somewhat paralysed. I’m not here to discuss the merits or lack thereof except to say that what is off the cuff termed misfortune has created a willingness in me to do some problem solving. The problem has been how to create a musical interface that would allow Drew freedom to express himself within the limits of his mobility.

I was quite happy at the beginning to fund this project myself, and surprise him with it fully functioning, and still would be had I the monetary resouces to accomplish this but I’ve ended up in famine mode and as a consequence that when I saw Drew today I put forward my ideas and asked if he’ed like to fund it himself. Drew was entirely chuffed and it may have even been surprising for me to turn up out of the blue with my schematics in hand ( I’d taken them along hoping he wouldn’t turn up and I was going to sell the idea to the other Vitamin S diehards)
So thats the introduction and here goes with the explanation of how it’ll work with brief explanation to begin on the mobility Drew has.
Complete use of vocality and use of arms and hands but not much dexterity therein therefore an instrument that uses the capability of voice uppermost with some control therein of parameters with the use of arms and hands.

Recently I’ve been playing around with frequency to voltage and loudness to voltage or the opposite of VCF’s and VCA’s. ACV’s and FCV’s as it were. I’ve been using these “transducers” to enable the change in voltage induced by changes in loudness and frequency to drive light emitting diodes, which go brighter when the voltage increases, to effect light dependant resistors, which as the light on them gets brighter the resistance accross them decreases so that, in effect changes in lodness and frequency changes resistances and resistance is one of the most important, along with voltage and current, abilities to influence what electronic circuits do.

So thats the trouble with electronics. It’s very hard to describe what an electronic circuit does without using electronics and because of the design process it isn’t always easy to describe what something actually does in the real world without again resorting to electrical descriptions… but I’ll try.

Essentially the instrument has two channels that can be mixed together. One is the voice channel, lets call it channel one, which has an effects send and return on it, which can be mixed independantly of the second channel. The second channel is an oscillator which can be tuned, or played as it were, anywhere within the audio spectrum, and can be set as a drone or changed to create melodies. This oscillator also has a low frequency oscillator, LFO, or sub audio oscillator which affects the audio oscillator with a rising and falling of amplitude, otherwise known as tremelo and can be set at below 1Hz, or one beat per second to about 12Hz, or about one beat per 120mS or 1/8 of a second. So we have these tow channels which can be mixed together or stand alone but now it gets interesting because there is another level of interplay between the two channels.
First the voice channels has two converters that are kind of a side chain thing. The loudness of the voice and the frequency of the voice.
As I explained above the loudness and frequency are converted to resistance changes and these changes are applied to the audio oscillator and the LFO and are switchable to one or the other. The loudness of the voice and the higher pitches of the voice can be used to quicken the LFO or raise the pitch of the audio oscillator. These change can be adjusted for depth of change which may or maynot effect the rate of change… I’m not absolutely sure what will happen and how it will happen, to the extent that the instrument could be termed musical, but it will make lots of noise which is, of course either discordant or “cordent”.

It was going to end there, which would have been alot of fun in and of itself, but some clever Harry at DIY stomboxes made mention of lap steels, slides and ebows… played through a talkbox! The talkbox got me because a signal is played into a compression driver speaker which sends the sound pressure waves up a tube which is then put in the mouth and the shape of the mouth plays it which is then picked up by a microphone. My problem then was creating another signal to be played and the obvious one was a theremin which I’ve recently had some succes with but I’m not sure how much because when I brought it out last monday Paul Crowther played his pedals through it but suffice to say I’ve got another signal creation process that suits Drews abilities.
So there we go, theremin to talkbox and tube into the mouth which is picked up by the microphone and goes through the two channels. I think it’d be a lot of fun and offer almost infinite possibilities to make sound with the mouth and some hand movements.
This is the first schematic and the one I posted at DIY stompboxes.
Drew Box 1
These are my early drawings of the box itself and how Drew would use it.
This is the somewhat final schematic of which I’ve dawn layups for to etch a PCB. I’ve also drawn up the scale dawings to build the internal aluminium framework but they are incredibly boring.
final draft
Even on this I realised I could switch the LDR’s about so maybe more things will happen as interconnections occur to me but I kinda hope not as it’s getting to be a quite complicated wee beasty. Next I’ll post some decent drawings of what it’ll actually look like and try to draw up a system diagram that shows, easily, the interconnections.

Precarious times spent at the Wine Cellar: Vitamin S.

enter here
This is the opening page and as such won’t change so this ends up at the bottom. I’ll just link out the pages as they are done and thats how it’s going to happen.

Wecome to my new home on the net about my adventures at Vitamin S.
I’ve started some pages which are at the top which you can got to by clicking them.
alias Dr K
This is a background about how I came to be doing what I’m doing.
Current bits and bobs
Is basically what I’ll be doing from here on in. New projects.
Early stuff
The stuff I had at the very beginning of my Vit S sojourn. The raw tools.
Warming up
Bits that are made tested, undergoing mods and entirely usable. Done and Dusted. From the beginning of Vit S until now. Workhorses.

What I want to do is continue linking to separate pages from these above headings. I wonder if it’ll work. I don’t like the blog thing where the early stuff disappears in the background. I prefer a webpage type format so I’ll try and work it that way. All I have to do is work out how to link second tier pages into the side areas from the first tier pages linked at the top.


Sean and Jon May'09