Microcontroller-Based Temperature Monitoring System - Electronic Engineering Guide
1. Introduction
A Microcontroller-Based Temperature Monitoring System is designed to measure and display ambient temperature in real time. This system is useful in various applications including industrial monitoring, home automation, and weather stations.
2. Objectives
• To design a system capable of real-time temperature
measurement.
• To use a microcontroller for data acquisition and display.
• To optionally store or transmit data for logging and analysis.
3. Components Required
• Arduino Uno or any compatible microcontroller board
• Temperature sensor (e.g., LM35, DS18B20, or DHT11)
• LCD Display (16x2 or OLED)
• Resistors and potentiometer (for LCD contrast)
• Power supply or USB cable
• Breadboard and jumper wires
• Optional: SD card module or Bluetooth/Wi-Fi module for data logging
4. System Overview
The system reads temperature data from the sensor and displays it on an LCD screen. Optionally, it can send the data to a cloud server or store it locally. The microcontroller continuously polls the sensor at regular intervals.
5. Sensor and Microcontroller Integration
The LM35 outputs analog voltage corresponding to temperature (10mV per °C), which is read using the ADC of Arduino. DS18B20 is a digital sensor using a 1-Wire protocol, while DHT11 measures both temperature and humidity and uses a digital output.
6. Circuit Design and Operation
Connect the temperature sensor to the analog or digital
input of the microcontroller. The LCD is interfaced using digital pins, with a
potentiometer controlling its contrast. Power is supplied via USB or external
5V source.
Typical LM35 connections:
• VCC to 5V
• GND to GND
• Output to A0 (Analog input of Arduino)
7. Software and Code Explanation
The Arduino IDE is used for programming. Temperature is
read, processed, and displayed every few seconds.
Example Code Snippet (for LM35 + LCD):
#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int sensorPin = A0;
void setup() {
lcd.begin(16, 2);
lcd.print("Temp Monitor");
delay(2000);
lcd.clear();
}
void loop() {
int reading = analogRead(sensorPin);
float voltage = reading * 5.0 / 1024;
float tempC = voltage * 100;
lcd.setCursor(0, 0);
lcd.print("Temp: ");
lcd.print(tempC);
lcd.print(" C");
delay(2000);
}
8. Applications
• Industrial environment monitoring
• Smart homes and IoT systems
• Agricultural climate monitoring
• Medical storage temperature control
9. Limitations and Improvements
• Accuracy depends on sensor calibration.
• External factors like direct sunlight can affect readings.
• Can be improved with wireless data transmission (ESP8266, BLE, etc.)
• Logging data to SD card or cloud enables historical analysis.
10. Conclusion
This temperature monitoring system is a versatile project suitable for students and engineers. It combines basic sensor interfacing with real-time data processing and display, and can be extended with data logging and IoT capabilities.