This document describes an automatic DC fan system using an LM35 temperature sensor that is controlled by an Arduino UNO. The system has two DC fans, one for exhaust and one for supply. It also has LED indicators and displays the temperature on an LCD. Based on the measured temperature from the LM35, the Arduino turns on the appropriate fans and LEDs. For example, if the temperature is below 20°C only the white LED is on, and between 26-29°C the supply fan is turned on along with white and yellow LEDs. The system aims to automatically control fans to regulate temperature in a greenhouse.

1. Automatic DC Fan Using LM35
Dosen Pengampu:
Ary Surjanto, ST., MT.
Muhammad Arman, ST., S.Psi., M.Eng.
C. Bambang Dwi Kuncoro, ST., MT.
Pratikto, Dr., Drs., MT.
D3 Teknik Pendinginan dan Tata Udara
Politeknik Negeri Bandung
2017
POLBAN

2. AUTOMATIC DC
FAN USING LM35
Base on Arduino
for Green House
English version
made by :
M. Daddy Refa M (151611015)
Nurlatifa Haulaini (151611019)
Ronito Halason (151611027)

3. Lecturer
Ary Surjanto, ST, MT.
C. Bambang Dwi Kuncoro, ST, MT
Muhammad Arman, ST., S.Psi., M.Eng
Pratikto, DR, Drs.,MT

5. Description
– We used LM35 as a temperature censor, the result of the measurements are
displayed on the LCD
– We used 2 DC Fan 12 volt, one for exhaust fan and another fan as a supply fan
– When the value of temperature under 20°C, LED white will shine and no fan is
working
– When the value of temperature around 26°C until 29°C, LED white and yellow
will shine, and supply fan will be working
– When the value of temperature above 30°C, LED red and white will shine,
supply fan and exhaust fan will be working

6. Source
– https://www.youtube.com/watch?v=18krZsFRzzY

7. The Equipment
 Arduino UNO
 LED : white, red and
yellow
 LCD
 Diode
 Resistor
 Wire
 Trafo
 DC Fan 12 volt
 PCB
 Relay Module
 Solder
 LM35

8. Arduino UNO R3
Consists of :
 14 pin digital input/output
 6 input analog
 Mikrokontroler ATmega328
 Koneksi USB
 Power jack
 ICSP header
 Reset button
Arduino UNO is a microcontroller
board based on ATmega328

9. Diode
 Diode are used for a half wave
rectifier
 AC current wave must be rectified
because we need a dc current
 The negative part connected to the
fan and positive part to the relay to
occur forward current
 LED are diode that can emit light
 LED are used as an indicator in
green house
 Red light indicates that the
temperature gets too hot
 Yellow light indicates that the
temperature in the normal
condition
 White light indicates that the
program are working

10. LM35
 The function : to change the
temperature scale into electrical
quantities in the form of voltage
 The value of voltage : 5V
 Has a calibration accuracy of 0.5°C
when the temperature 25°C
 Has a maximum range of temperature
around -55°C until 150°C
 Has a three plugs, the right side
connected to GND, the left side
connected to 5V, and the middle to
A0

11. LCD
Liquid Crystal Display (LCD)
LCD is a flat panel display or other
electronic visual display that use the
light modulating properties of liquid
crystals.
• Consist 16 character and 2 row
• can be observe with a 4 bit mode or
8 bit mode
• Equipped with back light
• In this project, LCD use to display the
value of temperature

12. Resistor
Resistor is electronic component
that serve to hold electric current.
Because of electrical currents
connected to electric voltage so that
when voltage is passed across the
resistor, there will be a decrease in
that voltage.

13. Trafo

14. Fan
• DC fan 12 volt
• The size : 12 cm x 12 cm
• We used 2 fan, one for
exhaust fan and another one
for supply fan

15. Relay Module
• Relay is switch are operated
electrically
• Relay has two electromechanical
components, witch consist of two
main parts they are electromagnetic
(coil) and mechanical (set contact
switches)
• Principle of electromagnetic relay
use to move the switch contacts so
that when the electric current is
small (low power), it can conduct
electricity with a higher voltage

16. Wood
Jumper

18. Object
Censor
LM35
Arduino
UNO
Actuator
Supply fan
Exhaust fan
Display
LCD
Indicator
LED white
LED red
LED yellow

22. To control the Arduino, we must input the program
by using software Arduino IDE. First we should adapt the
COM of the Arduino with our software. Then, we should
choose the same board between the Arduino and the
software . F.or example : Board Arduino Genuino, COM 3)

23. The trouble when making
“Automatic DC Fan”
– We must add the trafo and diodes because the current sources
from Arduino UNO only 5V but we need current sources more
than that
– It takes a lot of wire to connected the LCD with Arduino, so we
decide to change the wire and we use I2C
– we need to change the program on IDE because we use I2C