[sdiy] Reed Switch and Magnet Keyboard

[Ray Wilson]

Wow! I just want to thanks everyone who has responded on this topic. It has
all been very helpful. I'm going to go ahead and order some reed switches
and a variety of magnets and try a few things. I will publish the findings
on my site when I achieve a successful configuration.

Thanks to All

Ray


----- Original Message ----- 
From: "Theo" <t.hogers at home.nl>
To: "harrybissell" <harrybissell at prodigy.net>; "Tim Parkhurst"
<tparkhurst at siliconbandwidth.com>
Cc: "'Ray Wilson'" <raywilson at comcast.net>; "Scott Stites"
<scottnoanh at peoplepc.com>; "Synth-Diy" <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, December 10, 2003 9:58 PM
Subject: Re: [sdiy] Reed Switch and Magnet Keyboard


> I have salvaged a old industrial computer keyboard that used reed switches
> as the key contacts (the key switch assemblies come from TI).
> These keys are/where closer together than the keys on a piano keyboard and
> have no false trigger problems.
> The trick seems to use tiny magnets so the switches trigger only when the
> magnet is really close.
> To do this the magnets run from the top (off) to the middle of the reed
> contact (on).
> Some organ brands use a similar system for pedal key contacts where the
> magnets are in the "back-front side" of the keys.
> Maybe this could work also work in our case?
>
> Cheers,
> Theo
>
> ----- Original Message -----
> From: harrybissell <harrybissell at prodigy.net>
> To: Tim Parkhurst <tparkhurst at siliconbandwidth.com>
> Cc: 'Ray Wilson' <raywilson at comcast.net>; Scott Stites
> <scottnoanh at peoplepc.com>; Synth-Diy <synth-diy at dropmix.xs4all.nl>
> Sent: Thursday, December 11, 2003 5:23 AM
> Subject: Re: [sdiy] Reed Switch and Magnet Keyboard
>
>
> > (if I could find them I'd use) Tiny horseshoe magnets, with the reed
> switch
> > located across the gap.  As the magnet approaches the switch, the flux
> will
> > be concentrated through the switch vanes and tend NOT to leak to the
> > adjacent switches.  Might be harder to install
> >
> > H^) harry
> >
> > Tim Parkhurst wrote:
> >
> > > You might get a little extra 'breathing room' between the adjacent
> > > magnets/switches by offsetting every other magnet and switch assy. In
> other
> > > words, on one key the magnet and switch sits fairly close to the pivot
> > > point; on the next key, the magnet and switch sit fairly far away from
> the
> > > pivot point. One problem I see with this approach is that the switches
> > > sitting close to the pivot point will tend to close slightly earlier
> than
> > > the switches sitting further away. This might be such a minor timing
> > > difference as to be unnoticeable, but (if needed) you might be able to
> > > compensate by putting shims under the switches that sit further from
the
> > > pivot. This would raise them up slightly so that they would close
> earlier.
> > >
> > > Tim Servo
> > > "Imagination is more important than knowledge." - Albert Einstein
> > >
> > > > -----Original Message-----
> > > > From: Ray Wilson [mailto:raywilson at comcast.net]
> > > > Sent: Wednesday, December 10, 2003 5:11 AM
> > > > To: Scott Stites
> > > > Cc: Synth-Diy
> > > > Subject: [sdiy] Reed Switch and Magnet Keyboard
> > > >
> > > > Hi Scott (and list)
> > > >
> > > > You mentioned that you had made a keyboard using reed switches and
> > > magnets.
> > > > I want to outfit a set of piano keys in this manner and am
interested
> to
> > > > know how you kept adjacent key switches from being activated
together.
> I
> > > > have a source for some nice inexpensive reed switches and magnets of
> > > various
> > > > sizes and would appreciate your suggestions (and anyone elses who
> wants to
> > > > chime in).
> > > >
> > > > Thanks
> > >
> > >
>
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