1: Circuit diagram of the temperature-based fan speed control and monitoring using Arduino. Circuit diagram of the temperature fan speed control and monitoring is shown in Fig. It is built around Arduino Uno board (Board1), 16×2 LCD (LCD1), temperature sensor LM35 (IC1) and a few other components.
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The required temperature is set using temperature setting device like potentiometer. The temperature senses actual temperature. The controlling device like micro controller, takes both these temperatures as inputs and display them on display device. It compares actual temperature with set temperature. If actual temperature is higher or lower than require set temperature then it gives signal to temperature controlling device to increase or decrease the temperature and thus it tries to maintain the temperature within required limit. For example, the temperature controlling device is cooler/compressor and it is required to maintain cooling.
In this system as the actual sensed temperature increases above certain limit over set temperature, the cooling is increased using cooler/compressor and vice versa. Along with all these devices most of the temperature controller systems have visual indicators (like bulb, LED) for over/ under temperature and sound alarms for audio alert.So all these are basic building blocks of temperature controller system. The given project is a demonstration of such system. It uses LM35 as temperature sensor and DC motor as a fan as a temperature controlling device.
It utilizes Arduino board as controlling device and ATMega328 as a micro controller. It uses 16x4 LCD panel to display actual temperature, set temperature and other message and notifications. Also it has LEDs for indications and speaker for audio alarm.Some of the features of the system are1. Accurately measures and displays actual temperature with resolution of two digits after decimal point2. Set temperature range is from 0 – 100 oC3. LCD panel for message and notification display4.
Variable fan speed control5. RED, GREEN and BLUE LEDs for under / over temperature indications6. Audio alarm for under /over temperatureSo let us see how the system is built. First see the circuit diagram followed by its description and operation. Circuit description:1.
The output of LM35 sensor is connected to analog input pin A0 of Arduino board. Its Vcc pin (+) is connected to +5 V and Gnd pin (-) to ground2. Pot R1 is connected to second analog input A1.
Its two fixed terminals are connected to Vcc and ground while middle sliding terminal is connected to A1 pin3. Data pins D4, D5, D6 and D7 of LCD are connected to digital pins D5, D4, D3 and D2 respectively. En pin of LCDis connected to pin 11 and Rs pin is connected to pin 124. RW pin is connected to ground5. A 10K pot is connected to 3rd pin VEE of LCD to vary its brightness6. LED+ terminal and LED- terminal are connected to 5V and ground to turn on LED back light for LCD7. One 8Ω speaker is connected to digital pin 10 as shown8.
The anodes of three RED, GREEN and BLUE LEDs are connected to digital pins 6, 7 and 8 through 470Ω current limiting resistors. Their cathodes are shorted and connected to ground9. The analog output pin 9 drives DC motor (Fan) through transistor MJE3055. Pin 9 is connected to base of MJE3055 through current limiting resistor R2 and the collector output drives DC motor as shownHere is the snap of system arrangements.
Table of Contents.Temperature Based Fan Speed Control & Monitoring With Arduino:In this post we have described how to design Temperature Based Fan Speed Control & Monitoring With Arduino and LM35 Temperature Sensor. The microcontroller controls the speed of an electric fan according to the requirement & allows dynamic and faster control and the LCD makes the system user-friendly. Sensed temperature in Celsius Scale and fan speed in percentage are simultaneously displayed on the LCD panel.The applications areas of this project are air-conditioners, water-heaters, snow-melters, ovens, heat-exchangers, mixers, furnaces, incubators, thermal baths and veterinary operating tables.Components Required:1. Arduino UNO Board2. LM35 Temperature Sensor3. 2N2222 Transistor4. 16.2 LCD Display5.
1N4007 Diode7. 1K Resistor – 28. 10uF Electrolytic Capacitor9. 12 Volt Battery/ AdapterCircuit Diagram & Connections:Circuit diagram of the Temperature Based Fan Speed Control & Monitoring With Arduino & LM35 is shown above. Arduino is at the heart of the circuit as it controls all functions.
![Automatic Temperature Controlled Fan Using Arduino Automatic Temperature Controlled Fan Using Arduino](/uploads/1/2/9/3/129397856/702692262.png)
LM35 is a precision integrated circuit whose output voltage is linearly proportional to Celsius (Centigrade) temperature. It is rated to operate over a -55°C to 150°C temperature range.
It has +10.0mV/Celsius linear-scale factor.The 2N2222 transistor acts as a switch and controls the fan speed depending upon temperature. 1N4007 diode controls the fan from being damaged. LED glows whenever the temperature exceeds 60°C.Working of the Circuit:Temperature sensor LM35 senses the temperature and converts it into an electrical (analogue) signal, which is applied to the ATmega328 microcontroller of Arduino UNO Board.
The analogue value is converted into digital value. Thus the sensed values of the temperature and speed of the fan are displayed on the LCD. When temperature exceeds 30°C the fan starts rotating.A low-frequency pulse-width modulation (PWM) signal, whose duty cycle is varied to adjust the fan’s speed is used. An inexpensive, single, small pass transistor like 2N222 or BD139 can be used here. It is efficient because the pass transistor is used as a switch.Source Code/Program:The program for Temperature Based Fan Speed Control & Monitoring With Arduino is given below.
Simply copy this code and paste it in your Arduino IDE. Then compile the code and then upload it.Video Tutorial & Explanation.
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