Tales From The Pool Boy

Here i sit on at least a 15 year old office chair which periodically lurches up and down due to a malfunctioning gas piston. I ponder about the inner workings of a pool, pumps, filter baskets, which product is the best for removing iron/copper stains and general sanitiser levels when it dawns on me. For year i have seen people scanning items in stores with one of those red barcode readers and on movies like "Employee Of The Month" i have seen that they behave as a laser and can scan items from long distances >20m. I feel it is my duty as a pool service man to find out the truth behind the scanning devices, and as such have devised an experiment.

The round bottle compared to the square bottle seemed to have little effect in the ability to scan the barcode in that the algaecide and Pool Perfect both failed to scan at 30cm. A greater impact seemed to be the roughness of the surface being scanned. The BP200 was packaged in a sachet and did not provide a smooth surface when scanned with the barcode reader. This appeared to have reduced the distance of positive scanning by approimately 5cm. The size of the barcode itself appeared to not have a an impact on positive scanning as the BP200 had the largest of all barcodes and was unable to scan the same distance as the other two products tested.

In comparision to the movie "Employee Of The Month" and the scene where the cash register employee is able to scan a barcode from approimately 20m this at first glace seems not likely. The barcode scanner used in the above experiment appeared to not behaved as a laser (monochromic, low divergence source of light) and more so a diverging source. As such increasing the distance attempted to be scanned from meant a reduction in the intensity of light hitting the barcode surface. Though even using a laser barcode reader would still possibly not yield improved performance. A barcode scanner, despite the name, actually reads the barcode. As such the light emitted from the scanner hits the barcode surface, the black line regions absord the light and the non black regions bounce the light back to the scanner where it is assumed, a sensor detects the light waves and determines from them the original scanned barcode. With an increase in distance the reflection angle would become more apparent and more likely than not the reflected light would not hit the sensor surface of the barcode reader. For increased performance as seen in the movie, major modifications would need to be completed in order to get 20m distances. A laser light source would need to be used in the barcode scanner. The sensor mehcanism would need to be improved to allow for a greater area for reflected light to be gathered and finally the barcode would need to be placed get best scanability, directly infront. It is unlikely a common business would use a device with such modifications and the cashier in the movie is a lying bastard scanning an item with an ankle mounted scanner below the counter while appearing to be scanning the real item at a distance.

Please if you have any information regarding this topic, the scanners used in your store or general engineering knowledge of barcode readers post back :P


Queen Anne said...

Ahhh No one here would really have that regular contact with the barcode scanning devices besides you me and perhaps whee whiffany. Can't say I've seen the movie either... although as a casual check out chick, I feel qualified to vaguely comment on the things.

Not really. Scanning to codes at once can just bring up some interesting things. Not sure what the odds are of scanning baby food and tissues to come up with a $30 dog bone but... the mysteries of the scanners.