RoboCop: Distance Measurement and Workspace Safety

This project, RoboCop, is a real-time distance measurement system for enhancing safety at the workspace. It uses a Nano ESP32 microcontroller based on the Xtensa LX7 processor, HC-SR04 ultrasonic sensor for measuring distance based on the principle of echolocation, and the Modbus protocol to transmit distance readings over Wi-Fi. The system can be integrated with robotics applications and/or monitoring tools.

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Table of Contents

1. Usage
2. Features
3. Requirements
4. Project Structure
5. How to Build

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Usage

Overview

The system measures the distance of nearby objects using an ultrasonic sensor, calculates the value, and transmits it over a Wi-Fi network using Modbus TCP. Users can access this data using the Python client or any Modbus-compatible software.

Key Parameters

• Wi-Fi: Connects to the AirVandalRobot network with the password xxxx.
• Static IP Address: The ESP32 is assigned the static IP 129.xx.xx.xx.
• Modbus Unsigned Holding Register:
  • The measured distance is stored in the unsigned holding register at address 5.
  • This value is scaled as an integer (distance in cm multiplied by 100).

How to Use

1. Power on the Device:

   • Connect the ESP32 to a power source using the USB Type C terminal.
   • Wait for it to connect to the AirVandalRobot Wi-Fi network.

2. Clone the Repository:

   •     git clone https://github.com/UofI-CDACS/RoboCop_Safety_Device.git
     

3. Install project requirements:

   •     pip install -r requirements.txt
     

4. Move to Python_Client folder:

   •       cd Python_Client/
     

5. Client.py

   • Open the client_distance.py file
   • Edit the Server_IP

     • Replace with the IP address being displayed in the LCD screen of the RoboCop device you want to read

       • Example:
         SERVER_IP = "192.102.98.2"

     • Leave the port and holding register unchanged
       SERVER_PORT = 502
       REGISTER_ADDRESS = 5

6. Access the Data:

   • Use the provided Python client (Python_Client/client_distance.py) to read the distance value from the Modbus server:

     python client_distance.py

   • Alternatively, use a Modbus-compatible application (e.g., ModScan, QModMaster, Modbus Poll, etc):
     • IP Address: 129.xx.xx.xx
     • Port: 502
     • Register: 5 (holding register for the distance)
       • This Register stores 16 bit value of unsigned integers

7. View on LCD:

   • The LCD displays the device’s static IP and the measured distance in real time.

8. Testing:

   • Place objects in front of the ultrasonic sensor and observe distance changes on the LCD or Python client output.

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Features

• Accurate Distance Measurement:

  • Measures distances between 2 cm and 400 cm using an ultrasonic sensor.

• Modbus TCP Support:

  • Transmits real-time distance data over the network.

• LCD Display:

  • Displays the static IP and the measured distance.

• Python Client:

  • Reads and interprets the Modbus data.

• 3D Printable Enclosure:

  • Protects the hardware with custom STL files.

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Requirements

Software

• Arduino IDE
• Python 3.x
• Libraries: pymodbus, rgb_lcd, WiFi, ModbusIP_ESP8266

Hardware

• ESP32 microcontroller
• HC-SR04 ultrasonic sensor
• LCD display
• Wi-Fi network

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Project Structure

1. Arduino

Contains the Arduino code (robo.ino) to set up the ESP32 microcontroller, manage Wi-Fi and Modbus connectivity, and interface with the HC-SR04 ultrasonic sensor and LCD.

2. Python

Contains the distance_reader.py script to fetch distance readings from the ESP32 Modbus server using the Python Modbus library (pymodbus).

3. 3D_Models

Includes STL files for:

• Mounting the ultrasonic sensor.
• Housing the ESP32 and LCD.

4. Images

Visual documentation:

• block_diagram.png: High-level system workflow.
• wiring_diagram.png: Connection guide for Arduino, sensors, and peripherals.

5. Docs

Additional resources:

• Device datasheets (e.g., HC-SR04, ESP32).
• Project report.

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How to Build

Step 1: Hardware Setup

1. Connect Components:
   • HC-SR04 Ultrasonic Sensor:
     • TRIG pin → ESP32 D6
     • ECHO pin → ESP32 D7
   • LCD Screen:
     • Connect via I2C (SDA and SCL pins).
   • ESP32:
     • Set up on a static IP for Modbus communication.
2. 3D Print Mounts:
   • Use the STL files in the 3D_Models folder to 3D print the sensor and ESP32 mounts.

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Step 2: Software Setup

Arduino

1. Install the following libraries:

   • rgb_lcd for LCD.
   • ModbusIP_ESP8266 for Modbus communication.
   • WiFi.h for ESP32 Wi-Fi management.

2. Upload the Arduino code from Arduino/robo.ino to the ESP32.

3. Ensure your Wi-Fi credentials and static IP configuration match your network setup:

   const char* ssid = "SSID";
   const char* password = "PASSWORD";