I have worked for 2 years in the support of a manufacturer of such machines, so I can only speak for its devices, but with the devices of the competition it should be no different:
- There is a light barrier directly at the bottle entry.
If you insert a bottle, it switches on the conveyor belts.
turned again. In this step, exactly 4 things happen: A camera searches for the deposit logo of the bottle, recognizes the barcode and looks at the shape of the bottle. In addition, the weight of the bottle is also determined. However, the weight is not used to detect the bottle, but is only to ensure that no bottles with beverage residues or even full bottles are inserted. Who thinks that no one would do this: yet… Sometimes there are ducks who do.
For example, bar code and bottle shape do not match (because the bottle is wrinkled or even a foreign label has been glued to the bottle), the bottle is rejected as unknown.
If this barrier is not triggered at all or twice (because e.g. some joke cookie tries the trick with the cord), then there is a chargeback, i.e. the pledge value is deducted again… So such tricks don’t work.
But she lands on a table in the background of the vending machine (reusable bottles).
The typical shape of the bottle openings is looked at and the bottles are counted in it. At the same time, the bottle height is measured. This is also the reason why ironing bottles must always be open. If the height does not fit (because foreign bottle types are in it or ironing bottles are closed) the box is ejected again. After detection, the box is then driven into the area behind the vending machine.
If so, the receipt value is deducted from the cash register and the machine internally marks the receipt as redeemed. Copying any receipts and redeeming them multiple times does not work. By the way, the memory of the vending machines is usually set so that it has the issued receipts only 3 days “in the back of your mind”, i.e. they can actually only be redeemed in this way for 3 days. If someone comes with an older receipt, the market can accept it, but must first call the manufacturer to release it
By the way, the biggest sources of error, why the devices so often do not recognize bottles, are the bottle shape.If the bottles are crumpled, of course they do not have the expected contour. The same thing happens when the market staff does not clean the vending machines every day and the glass panes on the right and left are dirty in the bottle detection. Then the camera cannot distinguish between the shape of the bottle and the dirt and mistakenly recognizes the dirt on the discs as part of the bottle, which the database then rejects.