a paperless QR based payment system for Google Solution Challenge 2021


Readme Card


Readme Card

forthebadge made-with-python

Demo Video

Solution Challenge Demo Day

Project Aim

The aim of QRegister is to change the current POS receipt systems of stores all around, in order to replace paper receipts with environment-friendly digital receipts. Our hope is to decrease the amount of trees cut, oil produced, CO2 emitted for the production of paper receipts and get closer to a more green future.

We have developed a screen based on Raspberry Pi that generates QR codes specific to a purchase. The QR-codes contain data such as item name, store name etc. in a hashed form. We have also developed a mobile app that works both online and offline, which has a camera section that scans the mentioned QR code and uses the information it contains to generate the digital receipt of the purchase.

Basinda ODTU

QRegister Desktop


  • Inventor reading from text files
  • Receipt generation according to inventory
  • QR Code generation which includes all receipt data in encrypted form
  • Accessing Firebase Firestore to record the receipt data for future usage
  • Supported many operating systems including Windows, OS X, Linux, Raspbian…

Run from command line

Install requirements:

  • python install -r requirements.txt

Create a Firebase project

  • Put serviceAccountKey.json inside the firebase folder

Run GUI from command line:

  • python main.py

Optional arguments:

Parameter Default Description
-f –fill_inventory False fill inventory values
-n –not_execute False do not run gui app
-r –raspberry False set ui for raspberry pi
-u –update False update store data before running
-s –full_screen False run app on full screen

Frequently Asked Questions (FAQ)

Why should I prefer an electronic receipt?

Every year, in the United States alone, producing paper receipts takes about 1 million liters of oil, uses a million liters of water, destroys 10 million trees, generates 2 billion kilograms of carbon dioxide, and causes 137 million kilograms of solid waste. Take into consideration that most of the paper receipts are checked only once and then end up in the trash. Besides, the paper receipts are coated with BPA (Bisphenol A), a plastic chemical that is presumed to cause cancer, obesity, type 2 diabetes, and premature puberty. The paper receipts also increase the COVID-19 contamination by increasing contact at the supermarkets. Moreover, the receipts are very hard to store, carry and keep track of.

I don’t have cellular data. Will QRegister still function?

Yes. You will be able to view your receipts right away, even if you are disconnected. Once you connect to the internet, your receipts will be saved safely.

If I delete QRegister, will my previous receipts be deleted?

No. We are keeping your old receipts saved and safe. If you ever remove the app and re-download, your receipts will still be available.

We store every information users and cashiers need in your electronic receipts. Specifically, we store the supermarket’s name, branch, and location; the products’ names, barcode numbers, quantity, fax rates, and prices; the purchase’s date, time, total fax, and total price.

Is my data safe?

Yes. We use several Google technologies to keep your purchase data safe.

I did not understand some parts of the tutorial. Where can I get extra support?

You can receive support any time by contacting our support team via qregisterhelp@gmail.com.

Contact Information

We would love to hear your feedback and answer your further questions. E-mail our team at qregisterhelp@gmail.com We are a devoted team of four engineering students.

Humeyra Bodur, Alkım Dömeke, Deniz Karakay, Murat Kaş