Is it possible to program a homemade money counter device?

Question

Microcontrollers

The situation is as follows: there is a live outlet. It is almost impossible to keep a record of goods (farm products, you can’t stick barcodes, you can’t enter them into the database, etc.), in short, sellers have a wide scope for theft, it’s almost impossible to catch by the hand. In this regard, it became necessary to create some kind of cash accounting apparatus. The idea is this: a box for money, there is some kind of input device on it, which can only count how much money was put into the box, and how much was taken. I see the condition of the program as follows: the seller enters the purchase price and the banknote that he took from the buyer, the device gives out a figure, which is change, and based on these conditions, the device must remember how much the seller should put in the box, and how much to take for change.
The question is, what is needed to create such a simple device? If someone has similar ready-made solutions or has the opportunity to make such a thing to order, I am ready to pay for these services. Well, or at least point me in the right direction to solve this kind of issue.

Answer 1

it's called a checkout

Answer 2

It is very strange, there is such a thing as a ledger, double entry, income-expense, balance and receipt, withdrawal of a “cash” and a report .. Since ancient times, and without a cash, everything was considered on paper and accounts. And with the advent of the box office, everything remains the same!
https://ru.m.wikipedia.org/wiki/Double_entry

Answer 3

it's called an ATM...

Answer 4

To the scales, a video camera above them: what lies on the scales. Then in the digital data: the weight of that and the total cost.
As a whole - it should be a single recorder device ("black box" where you can not climb and open it, everything in it should be encrypted).
Remotes (2pcs): "what's on the scales?" from the buyer and the seller by the names of the goods (for control from 2 sides): until the button presses match, the goods are not hung and the amount is not displayed.
After highlighting the amount and payment - you can make the buttons "Received payment" and "Paid".