paybasz

Payment system for custom RFID or NFC cards (such as Dormitory access cards). This system is similar to the ones that are used in festivals.

About the project

• User manual: manual.md

Functionalities

• Support costom RFID and NFC cards/tags
• Transaction history
• Support multiple gateways at the same time
• Edit and save users
• Read account balance (from backend and from gateway)
• Staistics menu
• Function without internet access
• Wireless terminal (gateway)
• Add money to the account
• Credit line option for trusted users
• Support multiple types of relation databases

Backend

The backend project can be found within the backend/ directory.

Used technologies

• Spring-boot
• Thymeleaf
• Bootstrap 4
• All the required dependencies will be downloaded by the provided maven build tool

How to compile

Execute mvn clean install command or use the attached maven wrapper. (mvnw on mac and linux, mvnw.cmd on windows)

The compiled files will be available inside the target/ directory.

Available functionalities

Analitics view

• Basic statistics
• Full system action log
• Advanced statisics

Users view

• Search for any property
• Allow/deny user
• Edit user info
• Add money
• Pay using the web terminal

Transaction log

Add money

Add user

Pay

Gateways view

• List all of the available gateways

Export settings view

• Export users
• Export transactions
• Export system log

Firmware

The firmware project can be found within the firmware/ directory.

Used technologies

• C/C++
• Arduino CLI
• Arduino lib: lcdgfx (at least 1.0.4)
• Arduino lib: MFRC522 (at least 1.5.1, https://github.com/MakerSpaceLeiden/rfid)
• Optional dependency: minicom (for serial debugging, you can also use Arduino IDE)

How to compile and build

• Install Arduino CLI to the ~/arduino/bin/arduino-cli directory.
• Install lcdgfx (at least 1.0.4) and MFRC522 (at least 1.5.1). You might need to install them manually.
• Use the provided makefile (goals: cleanup, compile, build, serial, status)
• Recommended IDE: Jetbrains CLion IDE

PCB design

Used peripheries

Name	Estimated cost	Image
Esp32 DevKit v1 30pin	$4.50
RC522 SPI RFID antenna	$0.97
0.95" OLED Display SSD1331 SPI	$5.80
Membrane switch 4x5	$0.85
Piezo buzzer	$0.55
10k ohm resistor x 5
100 ohm resistor x 2
150 ohm resistor x 1

Prototype 1 - bread board

Prototype 2 - prototype board

Version 3 - PCB

Testing

There was a live testing this summer. It took place at the TTNY summer camp.

Test overview

• Overall it was a success
• Most of the cards found to be compatible (revolut, transferwise, dormitory cards, bank cards, some smartphones with NFC support)
• It didn’t get very wet, it didn’t break, there was no need to replace parts

Issues

• The box is blocked the sounds too well, so the buzzer did not sound.
• Due to a powerloss accident the DB was almost lost. Note: Do not put the server to any commonly used areas!
• A small transparent surface should be placed in front of the display.
• Don't override backups cause there might be data loss.

Ideas for improvement

• Louder piezo buzzer
• A new property for user to indicate that the settlement was completed
• More gateway debug possibilities needed
• Named items (eg.: #117 -> "Napi menü" 650 JMF / 5dl)
• Export to unique email per user