And some kind of bars like in barcode readers.=20
As I mentioned before, if some kind of bar can be used on the other side,
instead of a  =A8passive=A8pivot a rotary encoder could  be used.

Rodolfo=20

-----Mensaje original-----
De: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] En nombre de
Kerry Wentworth
Enviado el: Jueves, 30 de Diciembre de 2010 10:49 a.m.
Para: Microcontroller discussion list - Public.
Asunto: Re: [EE] Cheap, thin, 36mm linear encoder with one+ million cycles

I was just thinking of something similar, except I was thinking B&W film=20
negative passing through an optical interrupter, with gradual darkening=20
photographed on to it.

Kerry


RussellMc wrote:
>> Gray code encoders, if cheap enough, usually are rotary (I never saw one
linear
>> at least). Pretty expensive anyway.
>>    =20
>
> Gray code encoder can be optical or use other sensors
> Gray code can be a SINGLE track with multiple sensors spaced along it
> in such a way that they between them "see" a gray code. Mathematicians
> used to say it was impossible. Nowadays its done. I don't know how
> hard it is to get 6 or 7 bits.
> BUT if you can use and end of track detector then you need simply two
> detectors in quadrature on a single track. Very standard. cf eg
> mechanical wheeled mouse. Each axis ha one "track" and two sensors.
>
> 36mm / 6 bits is about 0.5 mm/bit. Somewhat fine.
>
> An optical "window" with width affected by position would probably be
> easy enough. read light level shining through "window" to get
> position.
>
>
>      Russell
>
>
>
>  =20



--=20
Internal Virus Database is out-of-date.
Checked by AVG Anti-Virus.
Version: 7.0.289 / Virus Database: 267.11.13 - Release Date: 10/6/05

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

__________ Informacisn de NOD32, revisisn 5746 (20101230) __________

Este mensaje ha sido analizado con NOD32 antivirus system
http://www.nod32.com



--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.