Oversize Faders?

[gavspav]

I'm not sure if this is the right place to ask but its worth a try.

I'm looking to build a custom midi controller with huge faders.

The longest I can find are 100mm but I'm looking for a length of up to
1000mm.

I believe that old style mixing desks/theatre equipment may have used
long faders like this.

Has anyone got any ideas that could help me out?

I am based in Uk.

Thanks,

Gavin

[Federico]

1000mm are 3 feet
I don't think such fader exists....
F.

[Boris Lau]

gavspav wrote:
> The longest I can find are 100mm but I'm looking for a length of up to
> 1000mm.

If you really need this, you might have to build such a beast yourself.
1000mm would be one 'tick' every 8mm, considering 7-bit MIDI values.
That's more like a switch than a fader, and I would construct it that
way, avoiding a resistor network and A/D converter.

Boris

--
http://www.borislau.de - computer science, music, photos

[gavspav]

Hmm thanks, that would seem to make sense.
Only problem is that moving the fader (7mm for example) would have no
effect.
Also if I had say 6 faders I'd need 700 odd switches!
But neither of these two are necessarily that bad a thing.

Anyone know how long the longest off the shelf faders are?

Gavin

On 24 Jan, 11:19, Boris Lau > wrote:
> gavspav wrote:
> > The longest I can find are 100mm but I'm looking for a length of up to
> > 1000mm.If you really need this, you might have to build such a beast yourself.
> 1000mm would be one 'tick' every 8mm, considering 7-bit MIDI values.
> That's more like a switch than a fader, and I would construct it that
> way, avoiding a resistor network and A/D converter.
>
> Boris
>
> --http://www.borislau.de- computer science, music, photos

[Richard Crowley]

"gavspav" wrote ...
> Hmm thanks, that would seem to make sense.
> Only problem is that moving the fader (7mm for example) would have no
> effect.
> Also if I had say 6 faders I'd need 700 odd switches!
> But neither of these two are necessarily that bad a thing.
>
> Anyone know how long the longest off the shelf faders are?

Maybe 150MM / 6 inches?

There are industrial devices such as you describe
(linear transducers, etc.) but you likely don't want
to pay 100s or 1000s of $$$ each for them.

For long straight-line throws like that, people usually
use some sort of mechanical arrangement (aircraft
wire & pulleys, rack pinion gears, etc.) which end
up at a conventional rotary pot.

I even remember a product which used a loop of
plastic with an alternating black/white line pattern.
You put your finger on it and moved it up and down,
and underneath the panel, they had a pair of optical
sensors which output logic pulses relative to the
direction and distance moved. But it turned out to
be not very popular because there was no hard
indicator of WHERE the setting was.

[Scott Dorsey]

gavspav > wrote:
>
>Anyone know how long the longest off the shelf faders are?

Look for "linear potentiometers" and not for faders. There are lots of
industrial linear pots that are used for position sensing in machine tools,
some of which are available up to a meter long. They are not cheap,
however. In Germany, Kollmorgen makes some.

A cheaper way of doing this is with a timing belt connected to a rotary
pot, with a button attached to a point on the timing belt. The amount of
distance available depends on the diameter of the pulley attached to the
pot. If you're in Germany, the guys at Synchroflex in Munich will sell
you all the timing belts and pulleys you'll ever need.

I think anything much longer than 25 cm is overkill.

Note that some old EMI consoles used quadrant faders, much like older
lighting boards. A lever is geared up to operate a rotary potentometer.
I find these very pleasant to work on, but they would be more difficult
to construct mechanically than a simple timing belt with knob.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Boris Lau]

gavspav wrote:
> Only problem is that moving the fader (7mm for example) would have no
> effect.
What effect should it have? The MIDI controllers have 127 bit values as
far as I know, there is no smaller increase.

> Also if I had say 6 faders I'd need 700 odd switches!
> But neither of these two are necessarily that bad a thing.
Yeah, it won't be easy. I'd try to build the switches myself - contacs
in a rail, and a metal plate attached to the fader that bridges the
contacts.
Wiring up the contacts with a bit pattern, or one by one...

Boris


--
http://www.borislau.de - computer science, music, photos

[gavspav]

Hey thanks for all your help. I'll do some research and try to work out
the way forward.
Boris - of course you're right. I wasn't thinking properly.
Thanks Alot,
Gavin

On 24 Jan, 14:11, Boris Lau > wrote:
> gavspav wrote:
> > Only problem is that moving the fader (7mm for example) would have no
> > effect.What effect should it have? The MIDI controllers have 127 bit values as
> far as I know, there is no smaller increase.
>
> > Also if I had say 6 faders I'd need 700 odd switches!
> > But neither of these two are necessarily that bad a thing.Yeah, it won't be easy. I'd try to build the switches myself - contacs
> in a rail, and a metal plate attached to the fader that bridges the
> contacts.
> Wiring up the contacts with a bit pattern, or one by one...
>
> Boris
>
> --http://www.borislau.de- computer science, music, photos

[Boris Lau]

gavspav wrote:
> Hey thanks for all your help. I'll do some research and try to work
> out the way forward.

How about putting LEDs onto moving dummy knobs and use a camera looking
at that thing from a calibrated position? With just a bit of image
processing routines you can compute MIDI controller values from the
positions. That way you make that beast as big as you like :-)

Boris

--
http://www.borislau.de - computer science, music, photos

[gavspav]

It's a thought.
I'm also considering using optical mice.
PS/2 protocol is mashing my head though.
Gavin

On 24 Jan, 15:02, Boris Lau > wrote:
> gavspav wrote: > Hey thanks for all your help. I'll do some research and try to work
> > out the way forward.
>
> How about putting LEDs onto moving dummy knobs and use a camera looking
> at that thing from a calibrated position? With just a bit of image
> processing routines you can compute MIDI controller values from the
> positions. That way you make that beast as big as you like :-)
>
> Boris
>
> --http://www.borislau.de- computer science, music, photos

[Arny Krueger]

"Richard Crowley" > wrote in message

> "gavspav" wrote ...
>> Hmm thanks, that would seem to make sense.
>> Only problem is that moving the fader (7mm for example)
>> would have no effect.
>> Also if I had say 6 faders I'd need 700 odd switches!
>> But neither of these two are necessarily that bad a
>> thing. Anyone know how long the longest off the shelf faders
>> are?
>
> Maybe 150MM / 6 inches?
>
> There are industrial devices such as you describe
> (linear transducers, etc.) but you likely don't want
> to pay 100s or 1000s of $$$ each for them.

I seem to recall that some of the early low-cost consoles used faders that
were composed of a standard round pot with pully on the shaft that was
operated by a string attached to a sliding knob in a track. Tascam?

[Roy W. Rising]

"Arny Krueger" > wrote:
>
> I seem to recall that some of the early low-cost consoles used faders
> that were composed of a standard round pot with pully on the shaft that
> was operated by a string attached to a sliding knob in a track. Tascam?
>
Yamaha PM-1000 (and others). I have a load of them if anyone's intereste.

But ... I really wonder why a 1 meter fader is sought!

--
~ Roy
"It's NOT the mic, it's NOT the preamp!"

[Arny Krueger]

"Roy W. Rising" > wrote in message

> "Arny Krueger" > wrote:
>>
>> I seem to recall that some of the early low-cost
>> consoles used faders that were composed of a standard
>> round pot with pully on the shaft that was operated by a
>> string attached to a sliding knob in a track. Tascam?
>>
> Yamaha PM-1000 (and others). I have a load of them if
> anyone's intereste.
>
> But ... I really wonder why a 1 meter fader is sought!

I don't think that anybody meant to say that. ;-)

Remember that most who post here are from a metric-challenged country.

[Scott Dorsey]

Roy W. Rising > wrote:
>"Arny Krueger" > wrote:
>>
>> I seem to recall that some of the early low-cost consoles used faders
>> that were composed of a standard round pot with pully on the shaft that
>> was operated by a string attached to a sliding knob in a track. Tascam?
>>
>Yamaha PM-1000 (and others). I have a load of them if anyone's intereste.
>
>But ... I really wonder why a 1 meter fader is sought!

So you can mix with your feet as well as you hands?
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[gavspav]

Yeah I do want to make an oversize midi controller that allows a decent
crowd of people to stand around and fiddle with.
Faders don't have to be 1m but thats the kind of scale I envisaged.
Arny when you say you 'have a load of them' do you mean the early style
faders or the Yamaha PM-1000
If you mean the faders then I am interested!

Gavin
On 24 Jan, 18:07, (Scott Dorsey) wrote:
> Roy W. Rising > wrote:
>
> >"Arny Krueger" > wrote:
>
> >> I seem to recall that some of the early low-cost consoles used faders
> >> that were composed of a standard round pot with pully on the shaft that
> >> was operated by a string attached to a sliding knob in a track. Tascam?
>
> >Yamaha PM-1000 (and others). I have a load of them if anyone's intereste.
>
> >But ... I really wonder why a 1 meter fader is sought!So you can mix with your feet as well as you hands?
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

[Andre Majorel]

On 2007-01-24, gavspav > wrote:

> I'm not sure if this is the right place to ask but its worth a
> try. I'm looking to build a custom midi controller with huge
> faders. The longest I can find are 100mm but I'm looking for
> a length of up to 1000mm.

RS Components sell a number of linear position sensors. Go to
radiospares.fr. Click on "Industrie". Click on "Composants
d'automatisme et de process" (process control). Click on
"Capteurs de déplacement rectiligne" (linear position sensors).
The longest they have is Sfernice REC139L40E103W06304, order
code 370-6054. 1 m. You won't like the price.

Finding the same page on their British site, rswww.com is left
as a exercise. A bunch of entries under "Sensors & Transducers"
but I'm not sure which it might be.

There are other proximity sensor technologies ; capacitive,
inductive, ultrasounds, etc. Some might do what you want at
lower cost.

Farnell tend to carry the same sort of products as RS.

http://uk.farnell.coml/

--
André Majorel <URL:http://www.teaser.fr/~amajorel/>
(Counterfeit: )
First rule of Usenet : if we don't have an answer, it's not a
good question.

[Roy W. Rising]

"gavspav" > wrote:
> Yeah I do want to make an oversize midi controller that allows a decent
> crowd of people to stand around and fiddle with. Faders don't have to be
> 1m but thats the kind of scale I envisaged. Arny when you say you 'have
> a load of them' do you mean the early style faders or the Yamaha PM-1000?
> If you mean the faders then I am interested!
>
> Gavin
> > --

Gavin ~ I'm the one with the "load" of Yamaha PM-1000 *faders* ... 40
channel types and two master types. All are "New In Box". The pots are
10K ohm, they use an aluminum wheel rolling along a rubber track. The
travel is 75mm.

--
~ Roy
"It's NOT the mic, it's NOT the preamp!"

[Richard Crowley]

"gavspav" wrote ...
> Yeah I do want to make an oversize midi controller
> that allows a decent crowd of people to stand around
> and fiddle with. Faders don't have to be 1m but thats
> the kind of scale I envisaged.

Build your big controller box with moving knobs in slots to
whatever scale is appropriate. Make it museum-strength
to resist public wear-n-tear. (Or whatever is appropriate
for your situation.)

Then when the mechanical part is done, rig some loops of
tough braided fishing line or equivalent with pulleys at the
two ends of each slider. You could rig all the "drone"
pulleys on one end all on the same shaft.

Measure the total travel you have and select pulleys with
1.25 x that diameter (because conventional rotary pots
don't have 360-degree travel.)

Put the pulley on one end of each slider on a standard
rotary pot and rig the cord around everything so that
moving the big slider knob turns the pot in a proportional
degree. (Pun not necessarily intended. :-)

That scheme gets you maximum flexibility with the mechanial
AND electrical parts, and is easy enough to build with parts
that you can buy (or make) easily.

I have done something similar for a public-use display.
By allowing some "slip", the rig is even self-aligning.