[chbot] Mouse Scroll Wheel Question

[Richard Jones]

<63478v$2202of at smtp.mailfilter1.ihug.co.nz> <46568.211.8.77.2.1203317438.squirrel at webmail01.lancs.ac.uk>
Message-ID: <7b339632cc17615ca9fe9008adca2ccf at ihug.co.nz>
X-Sender: rjtp at ihug.co.nz
Received: from 203-173-160-73.static.bliink.ihug.co.nz [203.173.160.73] with
	HTTP/1.1 (POST); Sat, 16 Feb 2008 18:32:31 +1300
User-Agent: ihug Webmail/0.1b
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit

Many thanks Andrew, 
I see that I shall have to wear my glasses in future before jumping to
conclusions about mice!
I'll have to use some of those dual sensors in my next micromouse to sense
motor reversals.
Just now I'm having some success with ultrasonic distance measurement and
the propeller proto board using the a->d converter circuit in the App Note
001 pdf to display 40kHz on the VGA screen.
Hoping to have it ready to show on Wednesday.
Cheers
Richard


On Mon, 18 Feb 2008 15:50:38 +0900 (JST), "Andrew Errington"
<a.errington at lancaster.ac.uk> wrote:
> On Sat, February 16, 2008 23:37, Richard Jones wrote:
>> A friend of mine wishes to use a mouse scroll wheel circuit as a low
> cost
>>  USB input for a software defined radio, removing the scroll wheel and
>> providing his own pulses from a rather nice 'knob'. Has anyone actually
> had
>> a mouse apart apart and figured it out? The initial assumption was that
>> the wheel would have an optical quadrature detector but there seems to
> be
>> only one optical detector, and I suspect that the inputs are multiplexed
>> from buttons etc. Any ideas welcome.
>>
>>
>> Richard Jones
> 
> Hi Richard,
> 
> In the mice I have dismantled I have found several variations in design
> (some quite elegant), but generally they fall into the two expected
types-
> opto-mechanical and electro-mechanical.  I think that electro-mechanical
> is most common as the requirement is for only a dozen or more clicks per
> revolution, whereas the mouse ball itself needed to generate hundreds
> (before the purely optical sensor was introduced).
> 
> The one that you describe is probably optical if the optical sensor is
> next to the wheel.  Even though you see only a single optical package
> there, look for 3 pins connected to it.  Often there are two optical
> sensors (offset, of course) moulded into one package.  The three leads
are
> one for each sensor (A & B) and a common connection.  I doubt that the
> buttons are multiplexed with the wheel quadrature, but there will be a
> button attached to the wheel as well somehow which might be confusing. 
It
> might be cleverly integrated mechanically with the wheel assembly, but it
> will have its own I/O line.
> 
> If it's electro-mechanical then look out for some weird bent spring wires
> inside the wheel itself.  Often there is a quadrature pattern of PCB
> traces etched onto a circular piece of board inside the wheel.  Spring
> contacts will pick up A B and Common traces.  Another design has a little
> spring that flicks one way for 'up' and the other way for 'down'.  You
> can't use quadrature techniques for this design.
> 
> By the way, if you're looking for a neat input switch take a look at
> Dickies P7531 Rotary Encoder.  It's hard to get now as it's been on
> clearance for a while, but it's nicely made (and currently cheap).
> 
> HTH,
> 
> Andrew
> 
> 
> _______________________________________________
> Chchrobotics mailing list
> Chchrobotics at lists.linuxnut.co.nz
> http://lists.ourshack.com/mailman/listinfo/chchrobotics