Automatic production accounting. What probes/sensors to use?

Question

Do it yourself

Help solve the problem:
There is a cabinet in which the product is loaded and unloaded throughout the day. We need sensors that can capture all changes in the amount of product. The product has a barcode, but no one will intentionally barcode it, nor will they specifically cover it. The product stands tightly and closes each other, i.e. the commit must be on the input/output.
The data is accumulated and automatically sent to a specific server.
And now the questions:
What sensors / system / software to use?
What analogues already exist?
Who can do or has already done this?

Answer 1

If you have a product of the same type with a known weight, then you can put the cabinet on an electronic scale and take readings from them.
The weight of the cabinet has decreased - it means the product has been removed, it has increased - it means it has been put down.

Answer 2

You can put a stationary scanner at the entrance / exit, for example, like this:
www.honeywellaidc.com/ru-RU/Pages/Category.aspx?ca...
www.honeywellaidc.com/ru-RU/Pages/Category.aspx ?ca...
www.datalogic.com/eng/products/automatic-data-capt...
www.datalogic.com/eng/products/automatic-data-capt...
www.datalogic.com/eng/products /automatic-data-capt...
And process it either in special software called WMS or load everything directly in 1s (if you use it).

Answer 3

It's unrealistic. Otherwise, "smart" refrigerators would have been made long ago. There were attempts, but guano comes out ...

Answer 4

Product in 5 types of packaging, different shapes and volumes. It stands on 5 shelves, the packaging is not mixed with each other.
The meaning of the account is that there are too many such structures and they are located on a vast territory, and online monitoring of the remains is needed.
Scales will not fit, since each weighs 400 kg, such scales will be expensive, and it’s not convenient. The premises are different, the floor is curved. The scales don't fit.

Answer 5

RFID
If RFID tags suit you, you can come up with a polling algorithm - every 5 seconds, for example, or at the exit from the premises.
And sometimes tasks are solved not technically, but administratively.

Answer 6

If I understand the situation correctly, then the only way out is with the use of a person.
Maybe it’s still possible to use some kind of equipment, in terms of a locker there are a couple of buttons, or a digital display, and with any manipulations a person presses +9, -3, -4, +18.
Store only one type of product in each cabinet.