CCaWMU POS

Touchscreen Point of Sale system for the CCaWMU (Computer Club at Western Michigan University) office. Members swipe campus ID cards to identify themselves, then tap price buttons to add/subtract from their balance.

Building

Requires Qt 5.15+, OpenSSL development headers, and a C++11 compiler.

qmake POS.pro
make

The binary must run from the same directory as prices.csv, nicks/, ids/, and transactions.txt.

Features

• Card-swipe authentication via MD5 hash of campus ID
• Touchscreen price buttons loaded from prices.csv
• Dark/light mode (dark by default, toggle via Admin menu)
• Transaction log viewer (last 200 transactions, color-coded)
• Balance/debt viewer (all users sorted by balance, grand total)
• Price editor (Admin > Edit Prices, with input validation)
• Dual logging: transactions.txt (plain text) and transactions.jsonl (JSON lines)
• CCaWMU branding with accent colors from cclub.cs.wmich.edu

Data Files

File	Description
prices.csv	Item prices: name,cents (positive = deposit, negative = purchase)
nicks/	One file per user, contains balance in cents
ids/	MD5 hashes of card IDs mapping to nicknames
transactions.txt	Append-only log: ISO_TIMESTAMP nick balance_after
transactions.jsonl	Append-only JSON log: {"timestamp":"...","user":"...","balance_after":N}

Prices Convention

Positive values are deposits (money added to account), negative values are purchases:

Deposit,100
Soda,-75
Monster,-200

Deployment

The POS auto-starts on boot via GNOME autostart. The run_pos.sh script launches the binary and fullscreens the window. Do not modify the window title ("MainWindow") as the fullscreen script depends on it.

Rollback: mv POS.bak POS to restore the previous binary.

Editing with Qt Designer

Use QtCreator or QtDesigner to modify mainwindow.ui. Keep the window title as "MainWindow".