Re: Low cost image sensor

Hi Paul,
Thanks for the reply.

Paul Carpenter wrote:
> On 28 Jun, in article
> <1119945188.468544.97470@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> allenb_deja@xxxxxxxxxxx wrote:
> >Hi,
> >I have been searching the web for a low cost image sensor.
> >The application is for reading a type of barcode, approximately 20mm x
> >5mm, but I could make do with an area as small as 10mm x 3mm. A
> >resolution of 0.1mm would be more than adequate, and I only require
>
> Are you really reading a 2D barcode as compared to normal 1D barcodes?
> In other words is the important factor the 20mm dimension which has to be
> read to 0.1mm resolution which actually means a minimum of 200 pixels
> realistically 400 pixels would be better to ensure the resolution.

This isn't a standard bar code, however the resolution in the Y
direction is much less critical, it only needs to be about 0.5mm. For
the X direction, 200 pixels would be more than adequate.

>
> You need a square pixel device for certain (not all are).
>
> >monochrome. Ideally I would like no moving parts, and no lens. The item
> >to be scanned would be placed directly on the sensor, illuminated from
> >behind.
>
> No lens at all or built in lens? There are plenty fo cheap lens manufacturers
> who no doubt make something you could use.
>
> >I have found something like the VV6501C001 from STMicroelectronics,
> >cheap enough for this application <$6 US, however the array size is 3.6
> >x 2.7 mm, and the resolution is much higher than I need, although this
> >is not a problem. Unfortunately the physical package does not allow
> >these to be stacked in a linear array, or else I could use 3 or four of
> >these type of devices.
>
> Why are you looking at an area scan (VGA res) device? Most 1D bar code
> scanning is either
>
> a) Moving optics and single photodiode sensor
>
> b) Line scan camera chip and simple lens
>
> >Any suggestions would be appreciated, for this to be cost effective, we
> >are looking at a maximum of $20US in small quantities.
>
> IF you scanning a 1D barcode and its orientation (matching in plane but
> may be mirrored), then kook at Line scan devices from manufacturers such
> as Sony, Silicon Video Inc and others.
>
> Last time I had a quote was for a 1024 pixel line scan from Silicon Video
> for less than 14 pounds in UK (about $18) for TWO devices.
>
> These types of devices are used all other the world in lots of equipment
> bar code scanners, copiers, faxes, even desktop scanners and many other
> places in industry.
>

The final product, will be a small handheld battery operated device,
the item to be scanned is placed on it, a button is pressed, and the
result is displayed on an LCD. The reason why I mentioned no lens, is
for mechanical simplicity and compactness, if the item is placed
directly on the lens, I would imagine that the sensor would need to be
some distance away.
Thanks,


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