fx for the wheelchair bound?

[sean k]

Where I go to do music one of the organisers is a paraplegic with limited use of his hands but full use of his brain and vocal chords. I've been thinking about something I could make for him for a while now and last night somebody threw some percussion stuff together and stuck it on a board and it was definitely a step in the right direction but still on the unfriendly side for his abilities.

A while back we were led somewhere, here on the forum, to old magazine articles and I was intrigued by something that worked by taking sound pressure into a carbon mic and using it to create voltage. It struck me at the time as something good for this man but it's gone under the carpet until last night.

So I'd like you guys to help me out and sort out a way to get going something thats mostly reliant on voice control with simple resistance changes that'll make a big difference so this man can have something to play with that really is an intriguing device. To these ends the resistances I'm talking about are pot resistances and I'll build them into a box, a big box, so the pots have big wheels on them that the man can easily move, say 100mm diameter toy truck wheels, and I'll support both ends of the pot shafts so a degree of abuse won't bugger the pots.

As you can see my intention is to get the signal with an electret then split it off three ways. One is normal for mixing into the other signal which are an oscillator with a LFO where the other two split signals from the input are used to create voltages to drive LEds that effect the LDR's strung accross the oscillators. 'Cause the 40106 has so many wee amps in it I've thrown another LFO accross the normal signal.

That leaves 1 more 40106 section to do something with.

At the very top is the end of earthtonesaudio's proximity device with only the driver with two stages of high pass filter to create the voltage cutoff. So as the vocals go low the drive to the osc drops and the resistance on the LDR goes high and so the osc goes low. Whether or not they sync up is not the point at all but the pot in parallel with the LDR and the cutoff's of the HPF might allow a little sync here and there.

In the middle is the Clari(not) LED driver and I'll use that to change the LFO speed for the audio freq oscillator. So this ones about loudness so the louder one is the quicker the LFO goes.

Does it look as if it'd work? How many pots are there? 9! shit, thats too many but then they aren't all important and a few are just set and forget. Something like this is what I envisage the finished product to be like.

[earthtonesaudio]

That's a really cool idea!

A few suggestions:

-You should probably put the resistors on the HPF (upper TL074) to some positive voltage,  unless you're using a bipolar supply.
-a cap in front of the 386 might be good
-resistor to ground coming off the (-) input of the lower op-amp, probably should be decoupled or else taken to a higher bias voltage, unless using a bipolar supply.
-assuming you're using the lowermost oscillator for a tremolo type effect, some resistance (1k-10k maybe) in series with the op-amp output, before the collector/cap junction, would give better results.

[JasonG]

humanity at its best! I hope your project goes well.

[sean k]

Thanks Guys, I've got those ETA, but no ideas about what I can do with 1 x 40106 section? some form of filter?

I'll be building the actual physical stuff first as I'm short of cash at the mo' and I looking forward to the challenge of making big wheels on little pots.

[ACS]

Theremin?!?!

[sean k]

Actually thats quite a good idea. I finally got the proper chips for the minimum Theremin, I'd been using something with 4049's and it was a prick to tune and ratchety sounding, and got it together in an enclosure yesterday then took it out to play but it was absconded, only for the length of the set, by Paul Crowther who makes the Hotcake and the Prunes and Custard pedals. I'd tuned it quickly and got the notes starting at about 100mm but Paul managed to get it out to about 800mm by twiddling with the pitch nulls. The only trouble I could envisage is getting the antenna at the right distance from the earth plane of the main body and still having it in a place where Drew, thats the mans name, could still get at it without tiring.


Anyways, I think I might have figured out a use for the extra 40106... if it acts the same basic way as 4049's.
A piezo is mounted at the bottom of a button topped enclosure, or shaft I suppose, with a spring between the actuator and the piezo so the action of creating voltage is less abrupt and spread out as it were. The voltage then does the old trick of firing an LED which drives the LDR on the bottom of a filter taken straight from the Morula... would the 40106 act enough like a 4049 to accomplish this?

God what am I thinking (wheres the "duh" icon?) If I make a minimum theremin I've got three spare 4069 inverters and they are pretty close to 4049's... the Morular uses 4. So now I've got one spare 40106 and two 4069's.

[aron]

What about a Yamaha breath controller. Instead of shouting, just blow.

[ACS]

Here's two more ideas, both would utilise a friendly ( and coordinated!) guitarist:

1. Use your roller idea to have him control your wah
2. Set him up with a talkbox - you do the playing, he shapes the sound.

[sean k]

Okay, um, the wind controller puts me out of a job and looking at all the other stuff required for it to control, I think it would be quite expensive, plus the finicky nature of those types of interfaces  ... but it's a good idea and I'll put it to him when the time is right. I think it's a dependance-independance kind of thing. Drew maybe wants to suffer a little for his art and something that makes him work, but not too hard, and works with the motor skills he has; I mean I may be presumptuous even doing what I'm doing but I have been watching him for a while now and I think something that is basically simple electronics that keeps his voice, but uses it... in conjunction with the motor skills he has would allow him to enact and react in ways that will work with him and maybe open up doors to complexities that previously hes maybe seen as a way of giving in. Even with what I'm going to attempt I may be crossing the line in offering something that may be seen as babyish but watching him last night with a tray covered in jangley bits and a few switches made me think that something like this might work.

And digital is kinda a no go area in some respects. Even analog synths get a bit of brow beating as the purists confer with each other the benefits, or lack of most likely, of the knob twiddlers. Its a fine line, a stupid line, but it is a line.

I don't want to think too hard about the reasons for doing this either 'cause I might talk myself out of it, which can be done very easily in these politically correct times, and basically just jump in and start building. I've figured out the basic internal framework and have a coupla square feet of aluminum sheet so I'll go inside now and do some drawings to scale.

I've got enough to do in the manipulative physical world but the talkbox is interesting, not neccessarily in the conjunction with idea, as we have these dependance issues that can be tricky, but in the sense of having a bunch of strings, even in unison for a drone, that could be effected using the talkbox principle. How does it work again? something to do with a sealed speaker connected to a tube which is played into the mouth then the output is mic'd. Strings along the bottom? Whammy bar out the end to change pitch... only a pickup and a 386, etc, required... hmmm       

[ACS]

Actually, does he have enough hand control to run a slide?

Here's what I'm thinking:

* Lap steel in open tuning
* Ebow (or DIY Ebow) to get the strings droning
* Slide, controlled to the best of his abilities
* Talkbox to shape it all

Here's a good how-to for the talkbox...

Could be interesting!

Aidan

[sean k]

Good Idea Aidan, I'd like to do an E-bow anyways at some stage and have a vague recollection that they are a frequency, I suppose LFO regions, played into a winding with a magnet in it so the magnetic field drives the strings.

Your idea definitely has potential and the only thing that comes to mind are arm rests so that he wouldn't have to prolong the amount of time the e-bow is held above the strings. Yeah, great lateral thinking but it'd be fairly long term for me to develop all those things.

I'm also thinking that the talkbox doesn't need string vibration driving the speaker... just some signal that isn't in the microphone circuit, say like a theremin output. Interesting way to add what is usually a very dry and boring output. And simple, theremin circuit to 386 and sealed speaker then tube in the mouth. Wonderful. Little bit more complicated than a summing resistor but worth the effort I think.

I do a little work with the local brain injury trust and we've been talking about getting my instruments involved for ages but nothing has happened as yet... and the whole idea was sparked off years ago when I did some prop instruments for a video shot and the singer from the band commisioned me to do some real instruments. It was early days and nothing really came of it, only one instrument worked and made it onto an album, but we had talked about making a bunch of simple instruments and then touring them around schools and suchlike to get kids interested in the possibilities of music making and how it doesn't need to be confined to the expense associated with proprietary instruments.

Anyways, I suppose what I'm saying is that I'd encourage any of us to get out into the community and see where we can use these skills to open up possibilities for people looking for new ways to see the world.

I know I'm wandering but I saw a documentary last night about a Jewish guy who left the States for Israel and became a full time Magician working in hospitals. He'ed done it part time while in the States, and the authorities were kinda blase about it, but the Isaeli hospitals were more more open to what he was doing and part of that is that the country is in a constant state of crisis. It's funny how the good stuff only really comes to the fore in crisis.

We've got abilities here that are quite phenominal and I'd encourage you all to think outside the square about the places in our societies where this can be appreciated. Good for us to step out of the comfort zone once in a while.

Sorry for being preachy and having you suffer through my diatribes...

[sean k]

Sh!t, I'm going to review the design after watching this

http://www.youtube.com/watch?v=fhO7mmz3XYo& amp;feature=related
Bit boring at the beginning as he drones on about his gear ( I can understand it though) but towards the end he plays the ghetto talkbox and YEAH 
Theremin, talkbox, mic... and maybe a few LFO's. And a send/ return for feedback... Oops, sorry, I'll stop now and actually do something.

[earthtonesaudio]

Good Idea Aidan, I'd like to do an E-bow anyways at some stage and have a vague recollection that they are a frequency, I suppose LFO regions, played into a winding with a magnet in it so the magnetic field drives the strings.

Your idea definitely has potential and the only thing that comes to mind are arm rests so that he wouldn't have to prolong the amount of time the e-bow is held above the strings. Yeah, great lateral thinking but it'd be fairly long term for me to develop all those things.

I'm also thinking that the talkbox doesn't need string vibration driving the speaker... just some signal that isn't in the microphone circuit, say like a theremin output. Interesting way to add what is usually a very dry and boring output. And simple, theremin circuit to 386 and sealed speaker then tube in the mouth. Wonderful. Little bit more complicated than a summing resistor but worth the effort I think.

I do a little work with the local brain injury trust and we've been talking about getting my instruments involved for ages but nothing has happened as yet... and the whole idea was sparked off years ago when I did some prop instruments for a video shot and the singer from the band commisioned me to do some real instruments. It was early days and nothing really came of it, only one instrument worked and made it onto an album, but we had talked about making a bunch of simple instruments and then touring them around schools and suchlike to get kids interested in the possibilities of music making and how it doesn't need to be confined to the expense associated with proprietary instruments.

Anyways, I suppose what I'm saying is that I'd encourage any of us to get out into the community and see where we can use these skills to open up possibilities for people looking for new ways to see the world.

I know I'm wandering but I saw a documentary last night about a Jewish guy who left the States for Israel and became a full time Magician working in hospitals. He'ed done it part time while in the States, and the authorities were kinda blase about it, but the Isaeli hospitals were more more open to what he was doing and part of that is that the country is in a constant state of crisis. It's funny how the good stuff only really comes to the fore in crisis.

We've got abilities here that are quite phenominal and I'd encourage you all to think outside the square about the places in our societies where this can be appreciated. Good for us to step out of the comfort zone once in a while.

Sorry for being preachy and having you suffer through my diatribes...

Great story.  Inspiration; it is contagious...

[sean k]

I've now decided on a schematic which adds in a theremin driving a talkbox plus simplfied one or two things and complicated others.


The theremin and talkbox where a little daunting, well frustrating actually, as the talkbox compression driver I'd found was at 25W and 16ohms but after googling talkbox driver I found some stuff that made me realise that the essential tuning of the talkbox depends of the sensitivity of the mic used and how loud or quiet the enviroment is in which it is used.

Given it'll be used in a mostly kinda quiet enviroment then I won't need to be driving the compression driver at full capacity and should be able to get away with 5W or so and not need a huge transformer to drive a power amp but get away with about 200mA and 22VDC with a TDA 1905 chip.

So it's all basically sussed and I've got the alloy and the rulers ready to start cutting the framework up. Alloy frame, wood bottom plate and 2.5mm clear perspex heat bent and wrapped over the top. The big 150mm knobs will be thicker, 6mm perspex, glued to the bottom of drilled right through knobs then wrapped with rubber over the thin perspex, again heat bent, to widen the surface area.

Major construction project  (wonder if it'll ever get done?)

The reason it hasn't actuall been started is that I'm out making money to afford to buy all the bits and given how expensive it's going to be and all the planning I've done I might even approach Drew about it. Less surprise more joint project.
This is whats been keeping me busy.
http://artbox.blogtown.co.nz/

[mth5044]

That is massive, man. Good luck with your good cause.

[ACS]

Awesome Sean!

Ka pai... Didn't realise you're a Kiwi mate - I grew up in Westport!  Been travelling for the last 7 or so years, but have pretty much settled permanently in Melbourne these days - almost home

Man do miss ol' Aotearoa...

[sean k]

Hey Aidan, no wonder you were thing out of the square or maybe in the same square. Che Bro!

[Zjay]

I think that this schematic was so ridiculous because it is not easy to make something like this. And it could be a good explanation for the talkbox. It might we can see a different explanation in the framework.

[Hides-His-Eyes]

This thread was a fantastic read

I'd have been looking along the lines of a lap steel with a slide and an ebow attached permanently on some kind of rails across the body so that you could rest your hand on top of it but still have access to the button- but I don't know how much use of his hands/arms he has, this is the kinda thing where you have to tailor what you're doing to the individual I guess.

[amptramp]

This is a great thread and I have sort of started looking at the last schematic and noticed something:  You have two bridge rectifiers operating off one transformer and feeding the same zero-volt ground.  At one point in the cycle, when the two upper taps on the secondary are negative with respect to the lower, the upper two taps of the winding will be connected together through the bridges, shorting the secondary.  The last time I wanted wall-wart type voltages, I just took the top off a wall wart, zip-tied it to the chassis and soldered to the plug.  Good luck with this project - once other people see what you have here, you may be able to manufacture these as a business where you have a lot of demand and virtually no competition.