Today we will discuss and learn about a very intersting topic that is based on “Automatic Room Temprature Controlling System Using Arduino with LCD interfacing“.Nowadays with the advancement of technology particularly in the field of micro-controllers, all the activities in our day-to-day living have become part of information technology and we find controllers in each and every application.The project will help us to maintain the temprature of our room.
- 1 Arduino Uno
- 1 LCD 16X2
- L293D Motor driver IC
- 12V DC Motor Fan
- Jumper Wires
- 9V Battery
- 9V Battery Holder Clip
The UNO is the most used and documented board of the whole Arduino family. Arduino is an open source computer hardware and software company.Arduino board designs use a species of microprocessors and controllers.The microcontrollers are typically programmed using a dialect of features from the programming languages C and C++. The boards are equipped with sets of digital and analog input/output (I/O) pins that may be interfaced to various expansion boards (shields) and other circuits. The boards feature serial communications interfaces, including Universal Serial Bus (USB) on some models, which are also used for loading programs from personal computers. Common examples of such devices intended for beginner hobbyists include simple robots, thermostats, and motion detectors.
The DHT11 is a basic, ultra low-cost digital humidity and temperature sensor.This product is 4-pin single row pin package.It is integrated with a high-performance 8-bit microcontroller. Its system of procedure ensures the great authenticity and extremely good long-term durability.It has excellent quality, fast response, anti-interference ability and high performance.The single-wire serial interface system is integrated to become quick and easy,Small size, low power, signal transmission distance limitation is up to 20 meters, permitting a variety of uses.
A liquid-crystal display (LCD) is a very thin but are actually composed of several layers. Those layers include two polarized panels, with a liquid crystal solution between them. LCDs are available to display absolute images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden, such as preset words, digits, and 7-segment displays,just like digital clock.LCDs are used in a wide range of applications including computer monitors, televisions. Small LCD screens are common in compact consumer devices such as digital cameras, watches, calculators, and mobile telephones, including smartphones.
L293D Motor Driver IC
A motor driver is an integrated circuit chip(16-pin) which can control a set of two DC motors simultaneously in any direction.There are 4 input pins for L293D, pin 2,7 on the left and pin 15 ,10 on the right,Left input pins will regulate the rotation of motor connected across left side and right input for motor on the right hand side.When an enable input is high, the associated driver gets enabled.Similarly, when the enable input is low, that driver is disabled.
12V DC Motor Fan
A DC motor is any of a class of rotary electrical machines that converts direct current electrical energy into mechanical energy.This DC or direct current motor works on the principal, when a current carrying conductor is placed in a magnetic field, it experiences a torque and has a tendency to move. This is known as motoring action. A DC motor’s speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings.
A jumper wire is an electrical wire or group of them in a cable with a connector or pin at each end , which is normally used to interconnect the components of a breadboard or other prototype or test circuit.Individual jump wires are fitted by inserting their “end connectors” into the slots provided in a breadboard.
When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the anode.The terminal marked negative is the source of electrons that when connected to an external circuit will flow and deliver energy to an external device. When a battery is connected to an external circuit, electrolytes are able to move as ions within, allowing the chemical reactions to be completed at the separate terminals and so deliver energy to the external circuit. It is the movement of those ions within the battery which allows current to flow out of the battery to perform work.
Circuit diagram of the temperature fan speed control and monitoring is shown in the figure above. It is built around Arduino Uno board , 16×2 LCD , temperature sensor DHT11 and some other components as well.
DHT11 is a precision integrated circuit whose output voltage is linearly proportional to Celsius (°C) temperature. It is operated over a 0°C to 50°C temperature range.
Temperature sensor DHT11 senses the temperature and converts it into an electrical signal, which is applied to the MCU through an analog-to-digital converter (ADC). The analog signal is converted into digital format by the ADC. The values of temprature and speed of the fan which has been sensed while the process will be displayed on the LCD. Temperature and monitoring will be done using Arduino. The MCU on Arduino drives the motor driver to control the speed of fan.
Fan speed control technique. A low-frequency pulse-width modulation (PWM) signal, usually in the range of about 30Hz, whose duty cycle is varied to adjust the fan’s speed is used. An inexpensive, single, small pass transistor can be used here. It is efficient because the pass transistor is used as a switch.
One disadvantage of this invention, is that it can make the fan noisy (easily audible) because of the pulsed nature of the signal.
#include<dht.h> // Including library for dht
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);
#define dht_dpin 12
#define pwm 9
byte degree =
lcd.print(” Fan Speed “);
lcd.print(” Controlling “);
lcd.print(“Circuit Digest “);
lcd.print(temp); // Printing temperature on LCD
if(temp <26 )
lcd.print(“Fan OFF “);
lcd.print(“Fan Speed: 20% “);
lcd.print(“Fan Speed: 40% “);
lcd.print(“Fan Speed: 60% “);
lcd.print(“Fan Speed: 80% “);
lcd.print(“Fan Speed: 100% “);
So now your Project is Ready to work ,Keep enjoying this project…….
So, Friends I hope you understand this project very well . In upcoming Tutorial I will be back with some new interesting Projects and we will discuss about some useful development topics. Here if you want to recommend that what I should write in upcoming Tutorial then please leave your comments. and if u need any help or query please don’t Hesitate to discuss with me. Thank You 🙂