Real-World-Prototype-Codes

This repository contains prototype codes that demonstrate how Arduino Opta PLC, Raspberry Pi, and Blockchain can work together in real-world IoT and supply chain contexts. The focus is on reliable data collection, secure communication (via Modbus TCP), and blockchain anchoring of sensor data for tamper-proof Digital Product Passports (DPP).

Code Walkthrough

1. Arduino Opta (Modbus Client – .ino)

This sketch configures the Arduino Opta PLC to act as a Modbus TCP client. It communicates with a Raspberry Pi acting as a Modbus server.

Uses the ArduinoModbus and Ethernet libraries in Aeduino IDE.

Establishes static IPs for both Opta (192.168.60.2) and Pi (192.168.60.1).

Polls three Modbus Holding Registers every second:

HR0: sensor voltage (mV → V)

HR1: sensor resistance Rs (kΩ)

HR2: normalized Rs/R0 ratio

It avoids small fluctuations by applying threshold filters (EPS). Only significant changes trigger new serial output, reducing spam.

Key Outcome: The PLC continuously monitors sensor values sent from the Raspberry Pi and can later use them to drive actuators or alarms.

2. Raspberry Pi (Sensor + Blockchain – sensor_blockchain.py)

The Python script demonstrates the data acquisition and blockchain anchoring pipeline:

• Sensor Interface

• Reads analog signals from an MQ gas sensor using an ADS1115 ADC via I²C.

• Performs calibration in clean air to determine baseline R0.

• Computes Rs and the ratio Rs/R0.

• Emission Data XML

Formats sensor readings into an XML payload:

<EmissionData>
  <DeviceID>MQ_01</DeviceID>
  <Timestamp>2025-08-17T10:00:00Z</Timestamp>
  <GasType>CO2</GasType>
  <Voltage unit="V">0.542</Voltage>
  <SensorResistance unit="ohm">9,800</SensorResistance>
  <RsOverR0>1.235</RsOverR0>
  <Location>Warehouse_A</Location>
</EmissionData>

Saves the payload as a timestamped .xml file in ~/dpp_samples/.

Blockchain Integration

Hashes the XML payload using SHA-256.

Anchors the hash to an Ethereum in-memory blockchain (EthereumTester).

Stores the proof of immutability on-chain, along with transaction details (TX hash, block number).

Key Outcome: The Pi acts as both a sensor gateway and a blockchain anchor node, bridging the physical and digital layers.

3. PLC Codes (.plcproj)

A separate PLC-IDE/ folder will later include IEC 61131-3 compliant PLC projects (.plcproj) created with the Arduino PLC IDE, showcasing ladder logic or structured text versions of the same workflow.

🔗 End-to-End Flow

1. Raspberry Pi reads CO₂ sensor → converts values → builds XML.

2. Raspberry Pi anchors XML hash on blockchain → proof of immutability.

3. Arduino Opta PLC connects to Pi via Modbus TCP → polls sensor values in real time.

4. PLC can use these values for decision-making (e.g., trigger ventilation, alarms, or actuators).

5. This creates a verifiable chain of trust:

Physical Layer (sensor) → Digital Layer (XML + blockchain) → Control Layer (PLC).

🚀 Getting Started

Hardware Requirements

• Arduino Opta PLC (Ethernet-capable PLC)

• Raspberry Pi (any model with I²C + Ethernet)

• ADS1115 ADC module

• MQ-series gas sensor (e.g., MQ-135 for CO₂ equivalent)

• Ethernet network (or direct cable Pi ↔ Opta)

Software Requirements

• Arduino IDE with ArduinoModbus and Ethernet libraries

• Python 3 with dependencies:

pip install adafruit-circuitpython-ads1x15 web3

• Local EthereumTester (built into Web3.py)

🎯 Use Cases

Supply Chain Sustainability: Tamper-proof CO₂ emission logs tied to Digital Product Passports.

IoT–PLC Interoperability: Real-time monitoring where industrial controllers can act on IoT sensor data.

Research Prototypes: Academic demonstration of blockchain-based sustainability tracking.

📜 License

This project is licensed under the MIT License – see the LICENSE file for details.