This project creates an automatic temperature fan controller using an LM35 temperature sensor, comparator, relay, and reference voltage. The circuit senses temperature and automatically controls a fan to keep the temperature within a set range. It was assembled, tested, and found to work satisfactorily by automatically turning the fan on or off based on temperature readings from the LM35 sensor.

1. AUTOMATIC TEMPERATURE
FAN CONTROLLER
AUTOMATIC TEMPERATURE
FAN CONTROLLER
Presenter:
MUHAMMAD FAZIL MEMON
Batch: 2016
Presented to:
Engr. LATIF SHAH
FACULTY OF ENGINEERING,SCIENCE AND TECHNOLOGY
(FEST) INDUS UNIVERSITY

2. ContentsContents
 Abstract
 Introduction
 Methodology
 Results
 Cost
 Conclusion
 References

3. AbstractAbstract
 This project is based on the working of temperature controller
using LM35 and fan as cooler. The circuit automatically senses
the temperature and works normally within a particular
temperature ranges.
 VR of 33k is using which the temperature can be controlled with
the help of a LM35 temperature sensor.

4. IntroductionIntroduction
 This project is based on the working of temperature
controller using LM35 and fan as cooler. The circuit
automatically senses the temperature and works
normally within a particular temperature range.

5. MethodologyMethodology
• It comprises of a LM35, comparator, relay and a reference
voltage to set the reference temperature.
 LM35: Temperature sensor which is calibrated in the Celsius
(Centigrade) scale with a linear degree to volt conversion.
Comparator :An accurate comparator (A1 of LM358) in order to
construct a complete thermal-controlled switch Reference
voltage.
 The preset (VR1) & resistor (R3) from a variable voltage
divider which sets a reference voltage (V ref) form 0V ~ 1.62V.
The op-amp (A2) buffers the reference voltage so as to avoid
loading the divider network (VR1 &R3).Relay.

6.  The circuit switches a miniature relay ON or OFF
according to the temperature
detected by the single chip temperature sensor LM35DZ.
 When the LM35DZ detects atemperature higher than the
preset level (set by VR1), the relay is actuated. When
the temperature falls below the preset temperature, relay
is de-energized.
MethodologyMethodology

7. Circuit DaigramCircuit Daigram
Fig. 1 Automatic Temperature Fan Controller Using LM 35Fig. 1 Automatic Temperature Fan Controller Using LM 35

8.  IC1: LM35
 DZ Precision Celsius (Centigrade) Temperature sensor
 LM358
 Dual single supply Op-amp.
 Q1:
 General purpose PNP transistor ( A1015,...) with E-C-B pin-out
 D1, D2:
 1N4148 silicon diodes (or 1SS133)
 D3, D4:
 1N400x (x=2,,,,.7) rectifier diodes
 ZD1:
 Zener diode, 13V, 400mW
 Preset
 (trim pot)
 2.2K
 (Temperature set point)
 (# 222 or 2k2)
List of ComponentsList of Components

9.  2.2K
 (Temperature set point)
 (# 222 or 2k2
 Resistors:
 ( 1/4W or 1/6W)
 R1 -- 470K
 R2 – 68K
 R3 -- 33K
 R4 -- 10K
 VR -- 10K
 Capacitors:
 C1 -- 100 nF
 C2 -- 1 µF
List of ComponentsList of Components

10. Fig. 2 Pin diagram of LM358 OP-AMPFig. 2 Pin diagram of LM358 OP-AMP
LM 35LM 35

11.  After designing, simulating, assembling, soldering and
testing the circuit, we came to the conclusion that our
circuit of the temperature based fan speed controller is
working satisfactorily.
 The construction hardware perfect.
 The total project work perfectly and has negligible
amount of unexpected functioning.
ResultsResults

12. Components Price
Resistors 50
Capacitors 70
Operational Amplifiers OPM 50
Transformer 150
Vero Board 100
Diodes 30
LM 35 IC 50
Power Supply Cable 30
BJT Transistor 20
DC Motor 150
TOTAL 700
CostCost

13.  [1]https://www.scribd.com/doc/110380630/Automatic-
Temperature-Controller-Using-Lm35
RefrencesRefrences

14.  The problem statement is implemented.
 Hardware part is halfway implemented.
 As the technology is going on developing day by
day, we prefer things to be done automatically and
in the same way our projects reduces the work to
mankind.
ConclusionConclusion