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In
a past OMNIview, we discussed how the smaller size of today’s electronic
devices gives us more design and engineering latitude. We pushed the size
envelope when one of our clients hired us to build a diagnostic device
that would require a very small barcode reader. One which could, despite
its small size, make the best use of existing data matrix barcode
technology. In our prospective design, space was so tight, no barcode
reader currently available would have suited our needs. 
The
data matrix barcode contains a lot of information.
The
plan was to communicate the information in the barcode to a printer and to
the assay detector in a tabletop diagnostic device we were developing.
We chose to use a NASA-developed scalable data matrix
standard, which offered the possibility of including an extraordinary
amount of data in a very small space (about the size of your little
fingernail). There was a mitigating factor, however. If the barcode image
was not properly printed and presented, the contained information could be
easily corrupted. Our challenge was to build the smallest possible reader
that correctly interpreted and relayed critical information even if the
printed image of the code itself was somehow blemished or distorted.
Specialized
optics and error correction algorithms.
We
developed an optics design that included a special lens and a customized
LED light source to supply consistent light intensity and uniformity as
the coded image was being read. As importantly, our perseverance in
advancing the state-of-the-art in barcode image processing allowed us to
make the best use of effective and robust error correction
algorithms.
The tiny barcode
contains a tremendous amount of data.
Our miniature reader has to decode the data even if the
printed image is not positioned perfectly on the plastic assay cassette.
The
end result was the successful development of a
miniature and easily manufacturable barcode reader, which improved
usability of an existing technology. The diminutive device is used to read
the data symbols on the assay cassette shown above. The reader (also
called a scanner) is tiny, about the size of a postage stamp, and weighs
only a tenth of an ounce. Compared to the smallest barcode reader
commercially available, it is less than half the size.
*
We have had many readers
inquire where they could purchase the barcode reader described in this
article for use in other projects. It was developed for a client to be
used in a specific application. It is not for sale or commercially
available from us or our client.
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