https://github.com/batushn/logic-gates-line-follower
This repository contains the circuit design and logic implementation for a Line-Following Robot built using 4 sensors, logic gates, and DC motors. The robot uses basic digital logic gates to determine motor speeds based on sensor input and follows a line efficiently.
https://github.com/batushn/logic-gates-line-follower
binary breadboard breadboard-prototype-testing electrical-engineering electronics linefollower linefollowing logic logic-circuit logic-gates logic-programming logicgates mechanical-engineering mechatronic-systems mechatronics
Last synced: 2 months ago
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This repository contains the circuit design and logic implementation for a Line-Following Robot built using 4 sensors, logic gates, and DC motors. The robot uses basic digital logic gates to determine motor speeds based on sensor input and follows a line efficiently.
- Host: GitHub
- URL: https://github.com/batushn/logic-gates-line-follower
- Owner: Batushn
- License: mit
- Created: 2024-12-14T17:00:39.000Z (5 months ago)
- Default Branch: main
- Last Pushed: 2024-12-14T17:54:16.000Z (5 months ago)
- Last Synced: 2025-01-28T22:36:55.690Z (4 months ago)
- Topics: binary, breadboard, breadboard-prototype-testing, electrical-engineering, electronics, linefollower, linefollowing, logic, logic-circuit, logic-gates, logic-programming, logicgates, mechanical-engineering, mechatronic-systems, mechatronics
- Homepage:
- Size: 5.86 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# **4-Sensor Line-Following Robot using Logic Gates**
This repository contains the circuit design and logic implementation for a **Line-Following Robot** built using 4 sensors, logic gates, and DC motors. The robot uses basic **digital logic gates** to determine motor speeds based on sensor input and follows a line efficiently.
---
## **Overview**
This line-following robot utilizes:
- **4 QTR sensors** to detect the position of the line.
- Logic gates (AND, OR, NOT) to process the sensor signals.
- Two **DC motors** controlled via an **H-Bridge Motor Driver** (L293D).
- Two **555 Timer ICs** to generate PWM signals for motor speed control.
The logic gates are implemented using **74HC series ICs**, and the robot adjusts motor speed dynamically to align itself with the line.
---
## **Components**
| Item | Quantity |
|---------------------------|----------|
| 10 kΩ Potentiometer | 2 |
| Diodes (LN4148) | 4 |
| 74HC04 (NOT Gate IC) | 1 |
| 74HC32 (OR Gate IC) | 2 |
| 74HC11 (AND Gate IC) | 2 |
| DC Motors | 2 |
| L293D (H-Bridge Driver) | 1 |
| 5V Power Input (Or regulate from 12V) | 1 |
| 12V Power Input | 1 |
| 5 kΩ Resistor | 2 |
| 1 kΩ Resistor | 2 |
| 5 nF Capacitors | 2 |
| 100 nF Capacitors | 2 |
| 555 Timer ICs | 2 |
| Single Channel Cables | 1m |
---
## **Circuit Design**
The robot consists of two main sections:
1. **Sensor Processing Unit**:
- **4 QTR sensors** detect line position and output **binary signals** (0 or 1).
- These sensor signals are fed into **NOT gates** (inverters), **AND gates**, and **OR gates** to implement the decision-making logic.
2. **Motor Control Unit**:
- Two **555 Timer ICs** generate PWM signals to control the motor speeds:
- **33% PWM** for slow speed.
- **66% PWM** for medium speed.
- **100% PWM** for full speed.
- The H-Bridge Motor Driver (L293D) controls the direction and speed of the motors based on the logic output.
---
## **Truth Table**
The robot's logic is designed based on the following truth table:
| S1 | S2 | S3 | S4 | Left Motor | Right Motor | Explanation |
|----|----|----|----|------------|-------------|------------------------------------|
| 0 | 0 | 0 | 0 | 0% | 0% | No input - robot stops |
| 0 | 1 | 1 | 0 | 100% | 100% | Robot moves forward straight|
| 0 | 0 | 1 | 0 | 100% | 66% | Robot adjusts slightly to the right |
| 0 | 1 | 0 | 0 | 66% | 100% | Robot adjusts slightly to the left |
| 0 | 0 | 1 | 1 | 100% | 33% | Robot turns slowly to the left |
| 1 | 1 | 0 | 0 | 33% | 100% | Robot turns slowly to the left |
| 1 | 1 | 1 | 0 | 0% | 100% | Robot turns sharply left |
| 0 | 1 | 1 | 1 | 100% | 0% | Robot turns sharply right |
| 1 | 0 | 0 | 0 | 0% | 100% | Robot turns sharply left |
| 0 | 0 | 0 | 1 | 100% | 0% | Robot turns sharply right |
| 1 | 1 | 1 | 1 | 0% | 0% | Robot stops |
| 1 | 0 | 0 | 1 | 100% | 100% | Robot moves forward straight |
| 1 | 0 | 1 | 0 | 100% | 100% | Robot moves forward straight |
| 0 | 1 | 0 | 1 | 100% | 100% | Robot moves forward straight |
| 1 | 1 | 0 | 1 | 100% | 100% | Robot moves forward straight |
| 1 | 0 | 1 | 1 | 100% | 100% | Robot moves forward straight |
---
## **Working Principle**
1. **Sensor Input**:
- The 4 QTR sensors detect the black line and provide binary outputs.
- Sensor values are processed through logic gates to determine motor actions.
2. **Logic Processing**:
- **74HC04** ICs (NOT gates) invert signals where necessary.
- **74HC11** ICs (AND gates) and **74HC32** ICs (OR gates) combine inputs to produce control signals.
3. **Motor Speed Control**:
- Based on the truth table, the two **555 Timer ICs** generate PWM signals at different duty cycles.
- These PWM signals adjust motor speeds to steer the robot and keep it aligned with the line.
4. **Motor Driving**:
- The **L293D H-Bridge Driver** receives the control signals and drives the motors in the desired direction with the appropriate speed.
---
## **How to Build**
### **Steps**:
1. Connect the **4 QTR sensors** to the breadboard and configure them to detect the line.
2. Wire up the **NOT gates (74HC04)**, **AND gates (74HC11)**, and **OR gates (74HC32)** according to the truth table.
3. Implement the **555 Timer ICs** to generate PWM signals for motor speed control.
4. Connect the **L293D Motor Driver** to the motors and integrate it with the PWM outputs.
5. Power the circuit with:
- **5V** for logic gates and sensors.
- **12V** for the motors.
6. Test the circuit:
- Adjust the potentiometers to fine-tune motor speeds.
- Verify the sensor logic and motor responses against the truth table.
---
## **Usage**
1. Power on the robot with the **5V** and **12V** power lines. You can use a regulator (like LM7805) or L298n's regulator.
2. Place the robot on a line (black tape or track).
3. The robot will:
- Adjust motor speeds based on sensor inputs.
- Follow the line smoothly using the predefined logic.
---
## **Features**
- **No Microcontroller**: This robot relies purely on **logic gates** and analog electronics.
- **Dynamic Speed Control**: Motors adjust speeds to correct alignment deviations with potantiometers.
- **Modular Design**: Easily customizable for additional sensors or motors.
---
## **Future Improvements**
- Add more sensors for better precision.
- Turning to the last direction with a flip-flop circuit to prevent crossing the line.
---
## **License**
This project is licensed under the **MIT License**.
---