SMRT-Pi

Edge computing layer for SMRT Payments — bridging barcode scanners, payment terminals, and NCR POS systems for intelligent pricing, cash-discount logic, and EBT eligibility handling.
Designed for Raspberry Pi 4 / 8 GB hardware with headless install and OTA updates.

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Repository Structure

smrt-pi/
├── README.md
├── LICENSE
├── docs/
│   ├── setup_guide.md
│   ├── headless_install.md
│   ├── AGENTS.md
│   └── architecture_overview.md
├── src/
│   ├── scanner_bridge/
│   ├── tender_logic/
│   ├── ui_bridge/
│   └── systemd/
├── tools/
│   ├── flash_image.sh
│   └── diagnostics.py
├── sample_catalog.json
└── tests/
    └── test_scanner_bridge.py

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Purpose

SMRT-Pi is a modular edge-service platform that:

• Intercepts and transforms barcode data before it reaches the POS
• Applies business logic (cash discount, EBT splits, tax)
• Communicates with encrypted pinpads/terminals
• Posts back payment results as if from native POS hardware
• Supports headless deployment and remote management

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Features

• Barcode-level logic and rewriting
• Automatic 4% PX15 markup with per-transaction EBT vs. non-EBT tracking
• Local computation of discounts, EBT & non-EBT subtotals
• Secure integration with pinpads for all tender types
• JSON-based message contracts with the POS
• OTA / headless install support (Tailscale, Zerotier, etc.)

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Hardware Requirements

• Raspberry Pi 4 (4 GB or 8 GB recommended)
• Official 5 V 3 A USB-C power supply
• MicroSD 64 GB (A1 / V30 class or better)
• Case with fan + heatsinks (recommended for stability)

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Quick Start

git clone https://github.com/SMRTCall/smrt-edge-pi.git
cd smrt-edge-pi/tools
sudo ./flash_image.sh

Insert the SD card into the Pi, power it on, and it will self-register on your network.

Local Development

python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

# Seed catalog with sample data
python -m scanner_bridge.main --seed sample_catalog.json < /dev/null

# Run services (separate terminals)
python -m tender_logic.main
python -m ui_bridge.main

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## Headless Setup

1. Copy your `wpa_supplicant.conf` and an empty file named `ssh` into `/boot`.  
2. Boot the Pi; it auto-connects, clones the repo, and configures itself.  
3. `systemd` starts `earthpi.service`, launching all agents.  
4. Access via SSH:  
   ```bash
   ssh [email protected]

Detailed instructions in docs/headless_install.md.

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Agents

• scanner_bridge — Reads raw barcode data, transforms payloads, and forwards to the POS.
• tender_logic — Calculates totals, applies cash-discount rules, splits EBT-eligible / non-EBT subtotals.
• ui_bridge — Provides local UI (display or HTTP) for selecting payment type and displaying totals.
• earthpi-agent — Supervisor, OTA manager, and telemetry service.

See docs/AGENTS.md for detailed specifications.

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License

MIT License — see LICENSE for details.

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Contributing

• Use feature branches: feature/<name>
• Submit pull requests with corresponding tests in /tests
• Keep modules decoupled — each agent should run stand-alone

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Contact

SMRT Payments / Kote — [email protected]
Vancouver / Portland area, WA / OR