UNIVERSITY OF WEST ATTICA
SCHOOL OF ENGINEERING
DEPARTMENT OF COMPUTER ENGINEERING AND INFORMATICS

University of West Attica · Department of Computer Engineering and Informatics

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Internet of Things

Traffic Light Sequence with Arduino UNO, ESP-01 and ThingSpeak

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

Angelos Vasileios Mantzoukas
Student ID: 19390128

GitHub · LinkedIn

Christos Pylarinos
Student ID: 20390278

GitHub

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Supervision

Supervisor: Panagiotis Karkazis, Associate Professor

UNIWA Profile · LinkedIn

Co-supervisor: Rania Garofalaki, Laboratory Teaching Staff

UNIWA Profile · LinkedIn

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Athens, January 2025

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README

Traffic Light Sequence with Arduino UNO, ESP-01 and ThingSpeak

This project focuses on the development of an automated traffic light system using an Arduino UNO, integrated with the ThingSpeak IoT platform for real-time monitoring and remote control. The system simulates a classic traffic light sequence and transmits its operational state to the cloud via an ESP-01 (ESP8266) WiFi module.

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Table of Contents

Section	Folder	Description
1	assign/	Assignment material for the Traffic Lights project
1.1	assign/Final-Project.pdf	Final project description in English
1.2	assign/Τελικη-Εργασία.pdf	Τελική εργασία (Greek)
2	docs/	Project documentation and theoretical background
2.1	docs/Electrical-Signal-Light.pdf	Electrical traffic light theory (EN)
2.2	docs/Ηλεκτρικός-Φωτεινός-Σηματοδότης.pdf	Θεωρία ηλεκτρικού φωτεινού σηματοδότη (EL)
3	src/	Arduino source code and execution outputs
3.1	src/A4/A4.ino	Arduino implementation – Scenario A4
3.2	src/B/B.ino	Arduino implementation – Scenario B
3.3	src/C1/C1.ino	Arduino implementation – Scenario C1
3.4	src/C2/C2.ino	Arduino implementation – Scenario C2
3.5	src/Output/A4.txt	Execution output for scenario A4
3.6	src/Output/B.txt	Execution output for scenario B
3.7	src/Output/C1.txt	Execution output for scenario C1
3.8	src/Output/C2.txt	Execution output for scenario C2
4	README.md	Repository overview
5	INSTALL.md	Usage instructions

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1. Features

• Classic Traffic Light Sequence:
  Automatically cycles through:

  • Red: 30 seconds
  • Green: 30 seconds
  • Orange: 20 seconds

• Real-Time Monitoring:
  Live visualization of traffic light status through the ThingSpeak platform.

• Bi-directional Communication:

  • Data Upload: Sends numeric status values to the cloud:
    • 1 → Red
    • 2 → Orange
    • 3 → Green
  • Remote Control: Reads values from Field 8 of the ThingSpeak channel to switch between normal operation and standby mode.

• Hardware Protection:
  Uses a voltage divider to safely step down Arduino 5V signals to 3.3V for the ESP-01 module.

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2. Hardware Components

• Microcontroller: Arduino UNO
• WiFi Connectivity: ESP-01 (ESP8266) module
• Circuitry: Breadboard, jumper wires
• Passive Components: Resistors (used for voltage division)

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3. System Architecture

3.1 Arduino Programming

The Arduino is programmed in C/C++ to control both the traffic light logic and network communication.

• Timing Control:
  Uses the delay() function to define each light phase.
• Network Communication:
  Sends AT commands to the ESP-01 to:
  • Connect to WiFi
  • Open TCP connections
  • Transmit HTTP requests to ThingSpeak

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3.2 ThingSpeak Integration

A dedicated ThingSpeak channel (ID: 2749755) is used for data visualization and control.

• Field 1: Red signal status
• Field 2: Orange signal status
• Field 3: Green signal status
• Field 8: Alert signal / remote control switch

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4. Logic and Analysis

The system periodically retrieves data from ThingSpeak in JSON format to determine operating mode:

• Value 0:
  Normal traffic light sequence (Red → Green → Orange)
• Value 1:
  Standby / out-of-service mode (Orange light only)

This allows remote intervention without physical access to the system.

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5. Setup Requirements

5.1 Hardware Setup

• Connect the Arduino UNO to the ESP-01 module.
• Ensure:
  • Arduino TX → ESP-01 RX through a voltage divider (5V → 3.3V)
  • Proper common ground (GND)

5.2 Network Configuration

• Configure WiFi credentials in the Arduino code using:

AT+CWJAP="SSID","PASSWORD"

5.3 ThingSpeak Configuration

• Insert the following into the code:
• Write API Key: For uploading traffic light status
• Read API Key: For reading control commands from Field 8

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6. Conclusion

This project demonstrates a practical IoT-based traffic control system, combining embedded programming, wireless communication.