Re: Optical Sensors and Post Slots

[Duncan Louttit <duncan@swallow.co.uk>]

Hi,

         I use Sharp GP20120. They are nothing like ideal with a sample 
rate of about 25/sec and indeterminate outputs if there is no wall within 
range, but they are easy to use.

         Regards,

         Duncan

At 14:07 06/07/04, you wrote:
>Hi,
>     Which sharp sensors are you using? I know some have a min dist of about
>3cm, i was wondering whether this would be sufficient
>------------------------------------------------------------------------
>Daniel Chia
>
>"Genius is one percent inspiration and ninety-nine percent perspiration."
>
>      - Thomas Edison
>
>E-mail: danielcjh@yahoo.com.sg
>MSN: danstryder01@yahoo.com.sg
>------------------------------------------------------------------------
>
>----- Original Message -----
>From: "Duncan Louttit" <duncan@swallow.co.uk>
>To: <micromouse@cs.rhul.ac.uk>
>Sent: Tuesday, July 06, 2004 20:20
>Subject: Re: Optical Sensors and Post Slots
>
>
> > Hi Everyone,
> >
> >          I was using the Sharp sensors that claim (and seem to be)
> > relatively unaffected by the wall material. I don't know exactly how big
> > the sensing area is at the shortish ranges involved, but I could clearly
> > see the effect on the mouse.
> >
> >          Certainly Cyclops has mechanical problems with wide slots that
>are
> > big enough for the microswitch sensors to get caught in.
> >
> >          Regards,
> >
> >          Duncan
> >
> > At 12:40 06/07/04, you wrote:
> > >Mainly aimed at Duncan.
> > >Regarding the detection of the 'slot' in the posts:
> > >Are you sure that it is not the change in reflection coefficient due to
> > >the fact that the posts appear to be made of different material from
> > >that used to make the walls.
> > >Certainly the 'standard' plastic components are white walls and 'cream'
> > >posts. Even Martin Smith's maze has melamine faced walls and painted
> > >posts I believe.
> > >I find it hand to believe that an optical sensing system would have a
> > >narrow enough beam-angle to readily detect the 4mm wide, 2mm deep
> > >depression present in the post.
> > >Regards
> > >--
> > >Martin J. Barratt
> >
> >