Roll-to-Roll-system

IIOT Course Project - Sag based speed/ Tension control in R2R system

A closed-loop Roll-to-Roll system integrating embedded control, real-time sensing, and IoT-based monitoring. The system uses an ESP32 for motor control and data acquisition, and a Raspberry Pi running a Dockerized IoT stack for communication, visualization, and storage.

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🚀 Overview

This project implements a sag-based control system for a Roll-to-Roll mechanism. The controller adjusts motor speed dynamically based on sag input, while system states (RPM, current, control signal) are streamed over MQTT and visualized in real time.

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✨ Key Features

• Closed-loop control using Proportional (P) control
• Sag input via Serial / IoT interface
• Bidirectional motor control (MX1508 driver)
• Encoder-based RPM estimation
• Current sensing using ACS712
• Real-time data streaming over MQTT
• Visualization using Node-RED dashboards
• Time-series storage using InfluxDB
• Fully containerized IoT stack using Docker (IoTStack)
• Edge deployment on Raspberry Pi (low latency, offline capable)

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🏗️ System Architecture

  +-------------------+
  |      nodes        |
  |-------------------|
  |  Control (P)      |
  |  Encoder (RPM)    |
  |  Current Sensor   |
  |           |
  +--------+----------+
           |
           | MQTT
           v
+------------------------+
| Raspberry Pi (Docker) |
|------------------------|
| Mosquitto (MQTT)      |
| Node-RED              |
| InfluxDB              |
+------------------------+
           |
           v
     Dashboard UI


     ## 🔧 Hardware Components

• ESP32 Dev Module
• DC Motor
• MX1508 Dual H-Bridge Motor Driver
• Incremental Encoder
• ACS712 Current Sensor
• Power Supply
• 3D Printed Mechanical Assembly

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🧠 Control Strategy

The system uses a Proportional Controller:

🌐 IoT Stack (Raspberry Pi)

The IoT backend is hosted locally using Docker via IoTStack, enabling modular and reproducible deployment.

Services Used

• Mosquitto (MQTT Broker)
  Lightweight publish–subscribe communication

• Node-RED
  Flow-based programming for:

  • Data processing
  • Dashboard visualization

• InfluxDB
  Time-series database for logging system data

Advantages

• Low latency (edge processing)
• Offline capability
• Easy scalability
• Container isolation

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🐳 IoTStack Setup (Raspberry Pi)

git clone https://github.com/SensorsIot/IOTstack.git
cd IOTstack
./menu.sh

docker-compose up -d