Arduino AD8495 K-Type Thermocouple Amplifier using ATmega328P with Proteus Simulation

Introduction

This microcontroller project demonstrates how to measure temperature using an AD8495 K-Type thermocouple amplifier interfaced with an ATmega328P (Arduino platform) and tested entirely in a Proteus simulation environment.
The system reads analog voltage from the AD8495, converts it into real-world temperature values, and displays results over serial communication.
It is a practical embedded systems project focused on sensor interfacing, ADC usage, and signal conditioning.
Such designs are widely used in DIY electronics, industrial monitoring, and laboratory instrumentation.
The project is simple, accurate, and ideal for learning the working principle of thermocouple-based temperature measurement.

How the Project Works (Overview)

A K-Type thermocouple produces a small voltage proportional to temperature.
The AD8495 amplifier conditions and amplifies this signal into a linear voltage suitable for a microcontroller’s ADC input.
The ATmega328P reads this voltage through its analog input pin, converts it into a digital value, and calculates the temperature using a calibration formula.
The processed temperature data is then transmitted via UART serial communication for monitoring.

Block Diagram / Workflow Explanation

1. K-Type Thermocouple senses temperature

2. AD8495 Amplifier converts thermocouple signal into a scaled analog voltage

3. ATmega328P ADC reads amplified voltage on analog pin

4. Firmware calculation converts ADC value to Celsius and Fahrenheit

5. Serial Terminal displays temperature readings

Key Features

• Accurate temperature measurement using a K-Type thermocouple

• AD8495 analog signal conditioning for stable ADC readings

• ATmega328P internal ADC utilization

• Real-time temperature output in °C and °F

• Fully testable using Proteus simulation

• Simple and readable Arduino firmware

Components Used

• ATmega328P (Arduino-compatible MCU)

• AD8495 K-Type Thermocouple Amplifier

• K-Type Thermocouple Sensor

• Resistors (signal conditioning & biasing)

• Serial Terminal (Proteus Virtual Terminal)

• 3.3V / 5V Power Supply

Applications

• Industrial temperature monitoring systems

• DIY electronic thermometers

• Embedded temperature logging devices

• Educational sensor-interfacing projects

• Furnace, heater, and process control prototypes

Explanation of the Code (High-Level)

The firmware uses the ADC module of the ATmega328P to sample the analog output of the AD8495 amplifier.
A fixed gain factor converts ADC steps into voltage.
A reference offset compensates for the AD8495 output bias.
The calculated voltage is converted into temperature using a linear formula.
Results are sent to a serial interface, allowing real-time observation in a terminal window.

Source Code

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// Arduino example code
int     analogPin = 0;     
int     val = 0;      // variable to store the value read
float   temperature;  // Temperature value in celsius degree.
float   gain = 0.00488;
float   ref  = 1.25313;
 
void setup()
{ //  setup serial
  Serial.begin(9600);          
}

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Proteus Simulation

In the Proteus environment, the thermocouple signal is emulated and fed into the AD8495 amplifier.
The amplifier output connects to the ATmega328P ADC pin.
A virtual serial terminal displays temperature readings in real time, confirming correct firmware behavior and signal scaling.

FAQs

Conclusion

This project clearly demonstrates a practical embedded systems approach to temperature measurement using a thermocouple.
By combining the AD8495 amplifier, ATmega328P ADC, and Proteus simulation, it provides an excellent learning platform for sensor interfacing.
The design is simple, scalable, and ideal for both students and hobbyists exploring real-world microcontroller applications.

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Arduino AD8495 K-Type Thermocouple Amplifier using ATmega328P with Proteus Simulation

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