Thermal Equilibrium Time Study Apparatus Using Arduino

Abstract

Knowing how heat passes from one object to another is an important aspect of learning about physics, and the concept of thermal equilibrium, where two bodies reach the same temperature and do not exchange heat anymore. We designed a basic and cost-efficient thermal equilibrium laboratory setup using an Arduino to simplify this concept in order to better observe and conduct research on it. The main objective of this project is to create a practical learning device that demonstrates thermal equilibrium in real time. This may be helpful in school labs or small experiments to demonstrate to students how heat moves and levels off between two objects. In this setup, two temperature sensors are connected to an Arduino microcontroller. The sensors are placed on two objects of different initial temperatures. The Arduino reads and compares the temperatures continuously. When the temperatures are equal or very close, the Arduino turns on an LED light to indicate that thermal equilibrium has been reached. This technique makes the observation and study of thermal equilibrium easy by removing the requirement for complicated equipment. The use of Arduino provides flexibility, automation, and real-time monitoring. In general, the concept brings together fundamental physics and simple electronics to make a helpful and informative device.

Introduction

Overview and Objective

This project focuses on simplifying the understanding of thermal equilibrium—the physical process where heat transfers from a warmer object to a cooler one until both reach the same temperature. Since observing this process directly can be challenging, the aim was to create an interactive, low-cost, real-time device that demonstrates when thermal equilibrium is reached, especially for educational use.

2. Device Concept

• Built using an Arduino Uno microcontroller and two DS18B20 temperature sensors, each sensor is attached to an object.

• The Arduino continuously monitors the temperature of both objects.

• An LED lights up when the temperature difference falls below a defined threshold (e.g., ±0.2°C), signaling that thermal equilibrium has been achieved.

• This setup serves as a teaching aid that combines basic electronics, programming, and physics principles in a hands-on manner.

3. Literature Review

• A comprehensive review was conducted using resources like Google Scholar, IEEE Xplore, ScienceDirect, and Arduino forums.

• Keywords included: thermal equilibrium experiment, Arduino temperature sensors, heat transfer visualization.

• Criteria: Projects had to include temperature measurement, use Arduino/microcontrollers, and be suitable for educational or low-budget setups.

• About 10 studies/projects were selected for detailed comparison based on sensor type, method of display, cost, and usability.

• The review helped refine decisions regarding:

  • Sensor choice (e.g., DS18B20)

  • Equilibrium detection method (temperature difference ≤ 0.5°C)

  • User-friendly features, like real-time LED indication

4. Methodology

A. Components Used

• Arduino Uno: Main controller

• DS18B20 Sensors (x2): For temperature readings

• 4.7k Ohm Resistors: For sensor pull-up configuration

• LED: Visual indicator for equilibrium

• Breadboard, Jumper Wires, Power Supply: For circuit assembly and prototyping

B. Circuit Design

• Sensors are connected using the One-Wire protocol.

• A pull-up resistor ensures reliable data communication.

• An LED circuit indicates equilibrium based on Arduino output.

• Initially built on a breadboard, then transferred to PCB after testing.

C. Software Development

• Programmed in the Arduino IDE using the DallasTemperature and OneWire libraries.

• Main code features:

  • Initializing sensors

  • Reading temperatures

  • Real-time comparison

  • Triggering LED if the temperature difference is within threshold (e.g., ±0.2°C)

• Code is modular for easy threshold or timing adjustments.

Conclusion

In this project, we were able to design and construct a thermal equilibrium study apparatus employing Arduino technology. The primary aim was to develop a system that is able to sense when two bodies attain thermal equilibrium and to give a distinct visual indication of the moment using an LED trigger. Utilizing temperature sensor DS18B20, the system constantly checks the temperatures of two diverse objects. As the temperature difference between them is within a specified limit—meaning that thermal equilibrium has been established—the LED lights up to indicate the same. This device provides an effective, affordable means of explaining and illustrating heat transfer and thermal equilibrium principles. The ease of design, paired with the versatility of the Arduino platform, renders it a superior educational device for students and educators alike. It makes it easier to visualize a key principle of thermodynamics in an interactive and hands-on manner, closing the loop between theoretical understanding and actual observation. In addition, the modularity of the system makes future upgrades possible. These enhancements can make the device even more useful in teaching environments, laboratory work, or science fairs. In general, this project not only succeeds in its main goal of detecting thermal equilibrium but also sets the stage for further explorations of heat transfer and sensor-driven automation. It proves how within reach technology such as Arduino can be used in order to build learning experiences in the discipline of science and engineering.

References

[1] Halliday, D., Resnick, R., & Walker, J. (2013). Fundamentals of Physics (10th ed.). Wiley. ? A comprehensive textbook on physics principles, including thermal equilibrium. [2] Cengel, Y. A., & Boles, M. A. (2014). Thermodynamics: An Engineering Approach (8th ed.). McGraw-Hill Education. ? Detailed explanations of thermodynamic concepts relevant to heat transfer and equilibrium. [3] Banzi, M., & Shiloh, M. (2014). Getting Started with Arduino (3rd ed.). Maker Media, Inc. ? A practical guide for beginners working with Arduino microcontrollers. [4] Monk, S. (2016). Programming Arduino: Getting Started with Sketches (2nd ed.). McGraw-Hill Education. ? Covers programming concepts used in Arduino-based control systems. [5] Arduino Project Hub. (n.d.). Temperature Comparison and LED Trigger Project. Retrieved from https://create.arduino.cc/projecthub ? Example projects and tutorials relevant to temperature sensing and LED control. [6] NPTEL. (n.d.). Basic Thermodynamics. Retrieved from https://nptel.ac.in/courses/112105123/ ? Online lectures and resources on core thermodynamics principles.

Copyright

Copyright © 2025 Aditya Murlidhar Wanaskar , Kunal Subhash Narote , Mr. Nitesh Hirulkar . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.