Sonar‑Controlled DC Motor System

A two-part embedded project that uses an ESP32, an ultrasonic proximity sensor (HC‑SR04), and an L293D motor driver to control a DC motor and visualize distance readings on an I2C LCD. A Python script runs on a PC to ingest and visualize the distance data in real time.

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Table of Contents

• Overview

• Features

• Hardware Requirements

• Software Requirements

• Connection Diagram

• Getting Started

  • Part 1: ESP32 Firmware (CODE.C)
  • Part 2: Data Visualization (Python)

• Usage

• Code Structure

• Troubleshooting

• Future Improvements

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Overview

The ESP32 continuously rotates a DC motor via an L293D H‑bridge, pausing at fixed angular steps to measure distance with an HC‑SR04 ultrasonic sensor. Measurements are displayed on a 16×2 I2C LCD (LiquidCrystal_I2cTUR) and streamed over serial to a PC. A Python script reads the serial stream, plots a radar‑style visualization, and logs raw data for offline analysis.

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Features

• Angular sweep distance measurements (sonar) in 4° steps up to 360°
• Real‑time display of distance on a 16×2 I2C LCD
• Bidirectional DC motor control (forward/reverse) via L293D
• Serial handshake protocol (RDY, FWR, Distance:<value>, CDR)
• PC‑side radar visualization with live plotting of measurements
• Data logging for offline analysis

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Hardware Requirements

• ESP32 Development Board
• HC‑SR04 Ultrasonic Sensor
• L293D Motor Driver
• DC Motor (9 V supply)
• 16×2 I2C LCD (LiquidCrystal_I2cTUR compatible)
• Piezo Buzzer (optional)
• Breadboard, jumper wires, 9 V battery (or equivalent motor supply)

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Software Requirements

• Arduino IDE (with ESP32 board support)

• Python 3.8+

• Python packages (install via pip install -r requirements.txt):

  • pyserial
  • numpy
  • matplotlib

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Connection Diagram

ESP32              HC‑SR04           L293D             16×2 I2C LCD         DC Motor           Buzzer
-----              -------           -----             -------------       --------           ------
3V3 ────────────── VCC              VCC                VCC                 + (9 V battery +)
GND ────────────── GND              GND                GND                 - (9 V battery -)
GPIO 13 ── Trig    ─                ─                  ─                   ─                  ─
GPIO 32 ── Echo    ─                ─                  ─                   ─                  ─
GPIO 25 ── Enable  ─  Enable1,2      ─                  ─                   ─                  ─
GPIO 26 ── IN1     ─  Input1         ─                  ─                   ─                  ─
GPIO 27 ── IN2     ─  Input2         ─                  ─                   ─                  ─
GPIO 21 ── SDA     ─                SDA                ─
GPIO 22 ── SCL     ─                SCL                ─
GPIO 14 ── Buzzer  ─                ─                  ─                   ─

(Replace motor leads and power lines according to your battery connector.)

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Getting Started

Part 1: ESP32 Firmware (CODE.C)

1. Open CODE.C in the Arduino IDE.

2. Ensure the following libraries are installed:

   • Wire.h (I2C support)
   • LiquidCrystal_I2cTUR.h (I2C LCD)

3. Verify pin definitions at the top of the sketch:

   #define enablePin       25
   #define directionPin1   26
   #define directionPin2   27
   #define buzzer          14
   #define proximityTrig   13
   #define proximityEcho   32
   #define SDA_PIN         21
   #define SCL_PIN         22

4. Upload to your ESP32.

5. Open the Serial Monitor at 115200 bps to observe the handshake and distance readings.

Part 2: Data Visualization (Python)

1. Navigate to the python/ directory.

2. Install dependencies:

   pip install -r requirements.txt

3. Configure the serial port in GROUP_03_2022510158_2018510126_2021510002_PYTHON_CODE.py:

   PORT = '/dev/ttyUSB0'
   BAUD_RATE = 115200

4. Run the script:

   python GROUP_03_2022510158_2018510126_2021510002_PYTHON_CODE.py

5. A radar‑style plot window will open and update in real time.

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Usage

1. Power up your ESP32 and motor supply.

2. The ESP32 prints ESP32: Ready signal received. when it gets RDY from the Python script.

3. The motor sweeps in 4° increments; each step:

   • Stops, triggers the HC‑SR04, displays Distance: on LCD.
   • Sends FWR then Distance:<value> over serial.

4. After 90 measurements, the ESP32 sends CDR and reverses sweep direction.

5. The Python script interprets those messages to animate the radar.

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Code Structure

├── Radar_Code.C           Arduino firmware for ESP32
├── Visualization_Code.py  PC‑side visualization
└── wiring_diagram.png     (Optional) high‑res diagram

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Troubleshooting

• No serial output: Verify USB connection, correct COM/TTY port, and baud rate.
• LCD blank: Check I2C address (default 0x27) and LiquidCrystal_I2cTUR library.
• No distance readings: Confirm HC‑SR04 Vcc/GND, proximityTrig (GPIO 13) and proximityEcho (GPIO 32).
• Motor not spinning: Ensure motor supply connected to L293D Vcc2, enablePin (25) set by analogWrite(enablePin, 255).

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Future Improvements

• Implement filtering (moving average, Kalman) on distances.
• Add web‑based dashboard via ESP32 Wi‑Fi.
• Switch to hardware interrupts for echo timing for higher precision.