Dual-pressure push switch like camera shutter?

P

Phil

Guest
Dear All,

Has anyone ever seen an off-the-shelf pushbutton that has two contacts,
one that's made on gentle pressure and a second that's made when you
press all the way down? Like the shutter button on most cameras.

I'm actually making a remote shutter release for my camera. I was going
to connect up just the main "take picture" contact, since I don't need
the autofocus in this case and it seems to work. But then I discovered
that another purpose of the first contact is to wake the camera up if it
has gone to sleep. Having a separate switch is not ideal since in this
case.

Any ideas anyone?


Phil.
 
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Phil wrote:
Having a separate switch is not ideal since in this
case.

Any ideas anyone?
Click to expand...
Could you just diode OR the switch to both contacts?


- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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On Mon, 2 Jun 2008, Phil wrote:

Dear All,

Has anyone ever seen an off-the-shelf pushbutton that has two contacts, one
that's made on gentle pressure and a second that's made when you press all
the way down? Like the shutter button on most cameras.

I'm actually making a remote shutter release for my camera. I was going to
connect up just the main "take picture" contact, since I don't need the
autofocus in this case and it seems to work. But then I discovered that
another purpose of the first contact is to wake the camera up if it has gone
to sleep. Having a separate switch is not ideal since in this case.

Any ideas anyone?


Phil.

I can't think of anything else that would make use of such a switch,
Click to expand...
so I suspect they aren't available off the shelf.

Find a scrap camera and take the switch out of that. For that matter,
if you can look at the switch you might discover it's a mechanical
arrangement that could be duplicated.

Have a real mechanical switch for the "take picture" switch, and then
a metal plate that when touched activates the other?

Have two microswitches, one above the other, and a shaft that when
pressed, activates the first microswitch, and if you press the
shaft further the second swithc is activated.

I think that's where you'll have to go, and then various variations
on that theme come to mind, like using slotted optocouplers instead
fo microswitches.

Michael
 
On Tue, 3 Jun 2008, Brendan Gillatt wrote:

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Hash: SHA1

Phil wrote:
Having a separate switch is not ideal since in this
case.

Any ideas anyone?

Could you just diode OR the switch to both contacts?

But he wants to activated two different things, but in the same
Click to expand...
mechanical space.

Like he said, press the button a tiny bit, and it adjusts
the autofocus (and activates the LCD panel if it had gone
to sleep). Press the button a bit harder, and the camera
actually takes a picture.

One button switch connected to two functions wont' allow
you to do the actions independently.

Michael
 
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Michael Black wrote:
On Tue, 3 Jun 2008, Brendan Gillatt wrote:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Phil wrote:
Having a separate switch is not ideal since in this
case.

Any ideas anyone?

Could you just diode OR the switch to both contacts?

But he wants to activated two different things, but in the same
mechanical space.

Like he said, press the button a tiny bit, and it adjusts
the autofocus (and activates the LCD panel if it had gone
to sleep). Press the button a bit harder, and the camera
actually takes a picture.

One button switch connected to two functions wont' allow
you to do the actions independently.
Click to expand...
I understood he just wanted to take a photo and the fact that it kept
going to sleep was preventing the shutter from being released. By ORing
them together the camera is woken up just as the photo is taken.

- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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Thanks for the suggestions. I ended up getting two of those mini
"tactile" button switches and gluing them one on top of the other. One
of then has a repeatably lower activation force than the other and
always closes first. The result is quite usable.

I did consider some sort of wire-or circuit, but it seems that when the
camera has gone to sleep only one of the pins has power on it, and it's
an odd voltage. Although it would probably be safe to short them
together, the camera was too expensive to take any riskes....

Cheers,

Phil.
 
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