Types and principles of operation of barcode scanners
A barcode scanner is a device that enables reading, decoding and sending to a computer data encrypted in the form of a barcode.
Principles of operation
The code is read as a result of a scan. The light that comes from the reader is formed into a thin laser beam that moves along the code to be read. At the moment, it illuminates a small point in the code. Then the light is reflected by the bright elements of the code, i.e. the breaks. Its dark elements, in turn, absorb this light. The light of the reader reads the photodiode. This is because it reflects from breaks and causes the formation of slightly stronger electrical signals in the reader. As a result of the lack of reflection, i.e. lines, the signals are weaker in turn. Depending on the thickness of lines and breaks, the duration of individual signals is also different. The duration of each subsequent pulse encodes data, which are then translated by the reader’s decoder into digits, letters and other characters, which are sent to the computer.
Scanner types by communication method
Desktop scanners – are connected to a computer using a USB, KBW or RS232 cable. They usually work with stands. Wireless scanners – work with Bluetooth connection. Industrial scanners – are a kind of barcode scanners, which are used to work in particularly difficult and demanding conditions, e.g. in warehouses, industrial halls, warehouses or cold stores. They have a tight and very durable casing, which is resistant even to multiple falls and mechanical damage. The casing is covered with rubber elements.
Scanner types according to the type of codes read:
Scanners that read one-dimensional codes 1D Scanners that read two-dimensional codes 2D
Scanner types due to the technique of reading codes:
LED scanners – in this case, LEDs are the reading element. Laser scanners – in this case the reading element is the laser beam. Scanners of this type are sometimes divided into linear (reading takes place thanks to a single laser beam) and multi-linear (reading the barcode takes place in any orientation thanks to many intersecting laser beams). Linerar imager scanners are very durable and resistant to all types of devices, which results from the use of scanning systems that do not contain moving elements, read all 1D codes also from LCD screens. A modern linear sensor captures the line of hundreds of pixels that contains a given barcode. Area imager-type scanners are an extension of linear imager technology. In this case, the reading element is the image sensor (similar to a digital camera). It takes a photo of the code and then decodes it to the correct, desired end data.
Categories: Tech
