A functional and accurate project that is perfect for beginners, and displays the current temperature and light levels. This project is not just about connecting sensors to a microcontroller board; it's about understanding the process of converting physical values (Analog Signals) into accurate, usable digital data.
Useful for many things - use it check the temperature in your server room, check how hot and fast your fireplace is burning, or check if the fridge is open. The ideas are endless!
Why Monitor Temperature and Light?
In engineering, Monitoring is the core of system control. This device can be applied in various situations requiring precision:
- Server Room Monitoring: Prevent damage to network equipment from excessive heat buildup.
- Fireplace Safety: Check the heat of a fireplace to ensure the combustion system operates efficiently.
- Smart Refrigerator Alert: Check if the refrigerator door is left open via the light level leaking in.
- Home Automation: Use as a basic sensor to automatically decide when to turn lights or air conditioning on/off.
In-depth Look at Components and Engineering Principles
The core of this project consists of essential components working in synergy as follows:
- Microcontroller (Arduino): Acts as the "main brain" for processing data from the ADC (Analog to Digital Converter).
- Temperature Sensor (e.g., LM35 or Thermistor): These sensors work by converting heat into a Voltage value that changes with temperature. The Arduino receives this value and calculates the correct Celsius reading using a linear equation.
- LDR (Light Dependent Resistor): This is a resistor whose value varies with light intensity. When more light falls on it, its resistance decreases. We use the principle of a Voltage Divider Circuit to convert this resistance value into a voltage that the Arduino can read.
- Display Module (LCD): Displays Real-time data, allowing users to know the current status instantly without needing to connect to a computer.
Analyzing the Program's Logic (Code Logic)
To obtain accurate and stable values, the Code's operational system is divided into 3 main parts:
- Data Acquisition: The program reads Analog signals from specified Pins using the
analogRead()command, which will yield a numerical value from 0 to 1023 (for a 10-bit ADC board). - Data Conversion:
- Temperature: The read value is calculated according to the specific formula of the sensor, e.g., multiplying by the resolution per voltage unit (5V / 1024) to convert it to millivolts, and then converting it to degrees Celsius.
- Light Level: Converts the 0-1023 value into a percentage format (0-100%) for easier user understanding.
- Display & Delay: The processed data is displayed on the LCD screen, and an appropriate delay (Interval) is set to prevent screen flickering and reduce CPU load.
You could always edit it to contain more sensors, or could add a datalogger module.
Future Expansion Guidelines (Roadmap)
This project is designed to be highly flexible (Scalable) so you can develop it further in the future:
- Data Logging: Add an SD Card module to log temperature and light values into a CSV file for historical data analysis (Big Data).
- IoT Integration: Connect with ESP8266 or ESP32 to send data to a Cloud system (e.g., Blynk or LINE Notify), allowing you to check values from anywhere in the world.
- V2 Preview: In the next version, I plan to integrate a Humidity sensor and a Real-Time Clock (RTC) module so the system can accurately record the date and time of anomalies.
V2 of this temperature logger will be way better, I'm planning on incorporating humidity and time!
This project is an excellent starting point for practicing C++ programming skills for microcontrollers and designing basic electronic circuits.