Weighbridge billing and management system for a landfill
A Windows desktop system that weighs every truck at the gate, bills it by vehicle and waste type, and keeps the accounts, in English and Lao. In production use.
- in production use
- v1.2
- user roles, with supervisor override
- 3
- screens, bills and reports
- EN + LO
Problem
Every truck entering the landfill has to be weighed, priced by vehicle and waste type, paid for or put on credit, and accounted for. Staff work in Lao, bills have to print on the spot, and the company's own loads must never be billed by mistake.
Approach
Built a Flutter desktop application for Windows with an encrypted SQLite database that reads weights straight from the weighbridge scale. It has three user roles with supervisor approval for sensitive actions, full audit logging, backup and restore, and a practice mode for training new staff without touching real data.
Result
In production use at the landfill: bills print on A4, A5 or thermal paper, credit bills are tracked until they're paid, accounts export to CSV and PDF, and internal-use loads are detected and handled automatically.
What it does
- Weighing: reads each truck’s weight directly from the scale, so nobody types it in.
- Billing: prices each load by vehicle type (per load) or by waste type, prints the bill on A4, A5 or a thermal receipt, and keeps a waiting list for trucks in the queue.
- Credit: bills for account customers go on credit and are tracked until paid.
- Accounting and reports: totals for any date range (or week, month and year to date), exported to CSV or PDF.
- Customers and vehicles: customer records with contact people and registered vehicles, searchable by plate number.
- Control: super user, manager and officer roles. Sensitive actions such as cancelling a bill need supervisor approval and a comment, and every event is logged.
- Safety nets: an encrypted local database, backup and restore, a single-instance lock, and a practice mode for training.
It runs locally on the weighbridge PC and talks directly to the scale and printers, with its data encrypted on disk.
Stack
- Flutter
- Dart
- Windows desktop
- SQLite (encrypted)
- Scale integration
- PDF / CSV export