how barcode scanners work

A Short Guide to How Barcode Scanners Work

From scanning items at the grocery store self-checkout machines to scanning our plane tickets when we travel, barcodes have become so pervasive in so many parts of our modern lives that it’s easy to overlook the technology that has completely transformed so many industries.

But now barcodes and, consequently, barcode scanners, are found everywhere: transportation, logistics, retail, manufacturing … even healthcare and government. (For example, check out the wide array of scanners available through CipherLab and Datalogic, two companies TSC partners with.)

Do you ever stop to wonder, though, how barcode scanners work, anyway?

If you have, you’re not the only one. Being in the Auto-ID industry, this is something a lot of our value-added resellers and their end user customers are interested in investigating.

So, let’s explore this some more.

How Barcode Scanners Work: Light, Reflection, Numbers & Computers

Though many kinds of barcode scanners exist nowadays – from image scanners to horizontal scanners and laser scanners – let’s look at the most basic type of barcode scanner, your typical wand scanner, to see how it works.

how barcode scanners work

(Of course, this looks a bit different than the original barcode scanner designed and patented by Joe Woodland – the inventor of the barcode – and Bernard “Bob” Silver in 1949.)

barcode scanners

*Source: https://www.google.com/patents/US2612994

 

Here’s how the process works using a typical wand scanner:

 

1) The barcode scanning head shines light (LED or laser) onto a barcode.

The LED light (often a single one in basic barcode scanner models) will scan one part of the barcode at a time. (A note: more advanced barcode scanners user laser beams with rotating mirrors or even cameras to take instant digital photographs of the barcodes.)

 

2) The light is reflected back to the scanner and then detected by a photoelectric cell (a light sensor).

Photoelectric cells, also known as photocells, are electronic devices that, in the case of barcode scanners, are designed to read reflected light.

Any of the white areas in the barcode below reflect the most light back. The black areas, on the other hand, reflect little to zero light.

different types of barcodes

 

3) The scanner converts these sequences of black and white stripes into decimal numbers.

If you remember in our post about how barcodes work, white stripes, when reflecting a lot of light, are converted into 0s. The black stripes, meanwhile, convert to 1.

This is because the computers connected to basic scanners can only recognize these two numbers.

 

4) The scanner sends this captured data to a computer, where it is analyzed by a software program.

The computer then detects these numbers as a code, also known as a sequence.

For the barcode example given here, the sequence is 95 digits long and split up into 15 different sections.

The captured data reveals a few things:

  • The type of barcode the scanner has read (in this case, a zero denotes a standard barcode)
  • Who the product manufacturer is
  • The exact product it is

And corresponds to price and other relevant information.

So, there you have it: how barcode scanners work!

 

Sources:

 


Comments

2 responses to “A Short Guide to How Barcode Scanners Work”

  1. Tamal Ghosh says:

    Thank you author for such a nice post. Keep ti up.

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