E&TC / ECE · Embedded and digital electronics · Final year project
Smart Room Temperature Controller ATmega
A room temperature controller using an ATmega microcontroller. It keeps the room at a set temperature by switching a heater (shown as a bulb) and a cooler (shown as a fan) on and off.
What is the Smart Room Temperature Controller ATmega project?
A room temperature controller using an ATmega microcontroller. It keeps the room at a set temperature by switching a heater (shown as a bulb) and a cooler (shown as a fan) on and off.
Key facts
- Branch
- Electronics & Telecommunication (E&TC / ECE); also suits Instrumentation
- Type
- Final year project · Intermediate
- Suitable for
- Diploma capstone and B.E / B.Tech final year
- Build time
- 4 to 6 weeks
- Estimated component cost
- ₹2,600 – ₹3,800
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Smart Room Temperature Controller ATmega works
- 12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V.
- The Temperature sensor measures the temperature that the system monitors or controls.
- The Push buttons and switches provide manual inputs and the power switch.
- The ATmega328P microcontroller with base board is the brain of the circuit: it samples the sensors, compares readings with set limits and switches the outputs.
- The Relay module switches mains or high-current loads such as lamps, pumps and fans from a low-voltage signal.
- The DC cooling fan moves air for cooling or ventilation.
- The 16×2 LCD with I2C adapter shows readings, status and messages to the user.
- The LEDs indicate status.
Block diagram
Inputs
Temperature sensorPush buttons and switchesController
ATmega328P microcontroller with base boardOutputs
Relay moduleDC cooling fan16×2 LCD with I2C adapterLEDsComponents list and cost
Typical prices from Indian online stores and electronics markets (Lamington Road, Budhwar Peth, SP Road). Buy from one store where you can to save on shipping.
| Component | Qty | What it does | Approx. cost |
|---|---|---|---|
| ATmega328P microcontroller with base board | 1 | Is the brain of the circuit: it samples the sensors, compares readings with set limits and switches the outputs. | ₹350 |
| Temperature sensor (LM35 / DS18B20) | 1 | Measures the temperature that the system monitors or controls. | ₹90 |
| Push buttons and switches | 2 | Provide manual inputs and the power switch. | ₹80 |
| Relay module | 1 | Switches mains or high-current loads such as lamps, pumps and fans from a low-voltage signal. | ₹70 |
| DC cooling fan (12 V) | 1 | Moves air for cooling or ventilation. | ₹120 |
| 16×2 LCD with I2C adapter | 1 | Shows readings, status and messages to the user. | ₹220 |
| LEDs (assorted) | 1 | Indicate status. | ₹20 |
| 12 V power adapter / step-down transformer | 1 | Supplies stable low-voltage power from the mains. | ₹250 |
| Light Bulb | 1 | Part from the design specification | ₹150* |
| Passive components, PCB and wiring kit | 1 | Crystal oscillator, resistors (assorted), capacitors (assorted), transistors / MOSFETs, cables, connectors and jumper wires, diodes, PCB / breadboard and ICs and IC sockets. | ₹445 |
| Wiring, PCB, soldering and enclosure | 1 | Project overhead | ₹450 |
| Demo model base / mounting board | 1 | Project overhead | ₹500 |
| Testing spares and replacements | 1 | Project overhead | ₹300 |
| Estimated total | Varies with brand, quality and city | ₹2,600 – ₹3,800 |
Prices are estimates for budgeting; items marked * depend on the exact size or model chosen. We confirm the bill of materials when your design is frozen, and components are charged at actual cost with bills.
How much does this project cost?
| Option | What you get | Cost |
|---|---|---|
| Components only | You buy the parts and build it yourself | ₹2,600 – ₹3,800 |
| Hardware / IoT Final Year | Working model or guided build, Circuit diagram and bill of materials, Firmware / code with explanation | from ₹9,999 + components |
| Capstone Project (CPE) | Working project or model, Black book in MSBTE format, Step-by-step explanation | ₹9,999 + components |
| Diploma ITR | 100% working source code, Project report PDF, PPT | ₹1,999 + components |
No GST and no hidden charges. Use the cost calculator for a quote with your deadline and add-ons, or see all plans.
Download the project brief (PDF)
Summary, working, components and cost and viva questions on one branded PDF to show your guide or team. To get it developed, contact us on WhatsApp.
What you submit with this project
- Working model with circuit diagram and program code
- Project report or black book in your university's chapter order (block diagram, circuit, calculations, results)
- Presentation for the review and final viva
- Synopsis for topic approval, if your college asks for one
E&TC / ECE viva questions on this project
What is the aim of the Smart Room Temperature Controller ATmega project?
A room temperature controller using an ATmega microcontroller. It keeps the room at a set temperature by switching a heater (shown as a bulb) and a cooler (shown as a fan) on and off.
Explain the working of your project in short.
12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V. The Temperature sensor measures the temperature that the system monitors or controls. The Push buttons and switches provide manual inputs and the power switch. The ATmega328P microcontroller with base board is the brain of the circuit: it samples the sensors, compares readings with set limits and switches the outputs.
Why is a microcontroller used in this project?
A microcontroller combines a CPU, memory and I/O pins on one chip, so a single low-cost IC can read sensors, make decisions in code and control loads without a computer.
How does the LM35 temperature sensor work?
LM35 gives an analog output of 10 mV per °C, so 250 mV means 25 °C. The controller reads it with the ADC and converts the value to degrees.
Why is a pull-up resistor needed with a push button?
Without it the input pin floats and reads random values. The pull-up keeps it HIGH until the button connects it to ground.
Why is a relay used?
It electrically isolates the 5 V control circuit from the high-voltage load. The controller energises the coil through a transistor, and the contacts switch the load.
How can fan speed be varied?
With PWM through a MOSFET: changing the duty cycle changes the average voltage and therefore the speed.
Explain the block diagram of your project.
The input section senses the real-world quantity, the ATmega328P microcontroller with base board processes it according to the program, and the output section displays the result and drives the actuators. The power supply section feeds every block.
Which communication protocols are used between the modules?
I2C for the display, RTC or motion sensor (only SDA and SCL lines), a single-wire digital protocol for the temperature sensor and analog inputs read by the ADC for the analog sensors. Each protocol was chosen because the module supports it and it uses the fewest pins.
What is the operating voltage of the circuit?
The controller and most sensors work at 5 V (ESP boards and some modules at 3.3 V). A 12 V adapter powers the board, and a regulator steps it down. Motors and relays get their own supply line so they do not reset the controller.
What is the difference between accuracy and precision?
Accuracy is how close a reading is to the true value. Precision is how close repeated readings are to each other. A sensor can be precise but inaccurate if it is not calibrated.
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