Engineers Garage

  • Projects and Tutorials
    • Electronic Projects
      • 8051
      • Arduino
      • ARM
      • AVR
      • PIC
      • Raspberry pi
      • STM32
    • Tutorials
    • Circuit Design
    • Project Videos
    • Components
  • Articles
    • Tech Articles
    • Insight
    • Invention Stories
    • How to
    • What Is
  • News
    • Electronic Products News
    • DIY Reviews
    • Guest Post
  • Forums
    • EDABoard.com
    • Electro-Tech-Online
    • EG Forum Archive
  • Digi-Key Store
    • Cables, Wires
    • Connectors, Interconnect
    • Discrete
    • Electromechanical
    • Embedded Computers
    • Enclosures, Hardware, Office
    • Integrated Circuits (ICs)
    • Isolators
    • LED/Optoelectronics
    • Passive
    • Power, Circuit Protection
    • Programmers
    • RF, Wireless
    • Semiconductors
    • Sensors, Transducers
    • Test Products
    • Tools
  • EE Resources
    • DesignFast
    • LEAP Awards
    • Oscilloscope Product Finder
    • White Papers
    • Webinars
  • EE Learning Center
    • Design Guides
      • WiFi & the IOT Design Guide
      • Microcontrollers Design Guide
      • State of the Art Inductors Design Guide
  • Women in Engineering

Temperature Controlled System

By Ganesh Selvaraj

 

Ever wondered how your Air Conditioner or Heater or Refrigerator adjusts its temperature automatically? The answer is a Temperature Control System. This article will show you how to build a model of such temperature control system using minimum components and without any complex circuit.

First, let us learn few terms.

Control System

Control System is a combination of various physical elements connected in such a manner so as to regulate/direct/command itself or some other device/system.

Feedback

Feedback is a fractional part of the past/present output which is fed back to the input. In case of positive feedback, it is added to the input and if it is negative feedback then it is subtracted from the input.

Types of Control System

Depending on feedback it is divided into two types:-

          1.  Open Loop Control System(Feedback is not present)

          2.  Closed Loop Control System(Feedback is present)

BLOCK DIAGRAM

Block Diagram for Temperature Controlled System

Now we’ll learn how to make a Closed Loop Temperature Control System.

Components Required

          1. Temperature Sensor LM35

          2. Op-Amp IC (LM324/741)

{         3. Motor Driver IC L293D

          4. Potentiometer-10k

          5. DC Toy motor

          6. Propeller

          7. 7805 Voltage Regulator

          8. 100uF Capacitor

          9. Multi-meter (Digital one is Preferred)

        10. A Breadboard

Description

Basically the circuit switches ON a toy motor fan connected to the motor driver whenever heat is applied to the temperature sensor unit using say a burning matchstick. The wind from the motor fan would blow off the matchstick and switches OFF itself automatically.

Temperature Controlled System

Here the Temperature is the output to be controlled. A feedback is generated using the sensor which is fed into comparator which acts as a controller here. And the power is the input.

The Temperature sensor LM35 is very accurate whose output is directly proportional to its surrounding temperature. For every 1°C of rise/fall in temperature, the output voltage of the sensor varies by 10mV.

Setup Instructions:

—-> At room temperature, the output of the sensor would be a stable value. Connect the sensor to the +5V and GND and then measure the voltage at the output pin using a multi-meter. Note down the value as V1 for further use. In my case I got 0.28 Volts. It is not necessary that you get the same readings since the value depends on Temperature of your room, Quality of the sensor, multi-meter, etc.

—> Now apply power to the potentiometer and take readings from the output of it. Adjust the potentiometer using a screw-driver in such a way that it’s output voltage is slightly higher than that of the voltage readings obtained from the temperature sensor output pin. This is your reference voltage V2.

(Note: The higher you set the pot voltage, the lesser sensitive you system would be. I set it to 0.35 Volts so that I get a quite sensitive system i.e. a system with quicker response to the temperature variation. If you set it with lesser variation from V1 voltage then the system would respond even for small temperature changes also and would switch ON or OFF the fan faster.)

—> Now assemble the other components as per the given circuit. Connect the propeller to the motor axle to make the fan.

—> Mount the fan firmly on a small plastic or carton box to so that it can rotate freely.

I used electrical tape to attach it to the box since it was a cardboard box.

Temperature Controlled System

 

Position the fan in such a way that when turned ON, it directly blows wind onto the LM35 IC.

 Set up and Working

This is how my setup looks

Temperature Controlled System

 

—> Power ON the circuit and bring a heat source (burning matchstick in my case) close to the temperature sensor. Now the temperature close to the sensor is increased and thus it sends a feedback to the comparator.

If everything is done right then the motor would start spinning within few seconds and would blow heavy air on matchstick, extinguishing the fire. After a few second the motor will automatically stop spinning.

Caution:  

1. Make sure you keep away from the propeller blades while the fan is in ON state. It may be weak normally but while revolving at high speed, the propeller can hurt you easily.

2. Since we’ll be using a burning matchstick to apply heat to the sensor so care should be taken. Isolate the temperature sensor away from any wires or any other components and take some precautionary measures.

  Do it in a well-ventilated room.

Working

Initially, at room temperature, V1 < V2 and hence the output of the comparator is low so the motor is in OFF state.

When heat is applied on the temperature sensor using a burning matchstick, the output voltage of the sensor V1 gradually increases. This generates a feedback signal. When the output voltage of sensor V1 exceeds the reference voltage V2 set by the pot, the comparator’s output goes high and hence turns ON the motor through the motor driver.

When the motor turns ON, It produces high velocity wind and blows off the matchstick. Now since the heat source is turned OFF, the temperature sensor starts cooling and there by its output voltage V1 reduces gradually. When V1 falls below the reference voltage V2, the comparator’s output again goes low and hence turns off the motor. No matter how many times you try, the fire on matchstick put near the sensor will be blown off.

Advantages of this circuit:

         1. No complex circuitry.

         2. Cheap

         3. No need of any advanced programming or Microcontrollers.

Conclusion

Air conditioner, Heater, Refrigerator works on the same principle but the difference is that it uses more advance equipments to do the job more precisely. Take the AC for example. You set it to a particular temperature say 17°C and so the AC works only till it cools down the room temperature until it reaches the pre-set temperature and then switches off. After a while the temperature would rise above 17°C and then the AC would again start working only until it brings the temperature to the pre-set value again.

More Images of the Circuit

Temperature Controlled System

 

Temperature Controlled System

 

 

 

Circuit Diagrams

circuit-diagram_0

Project Video


Filed Under: Electronic Projects
Tagged With: temperature controlled system
 

Questions related to this article?
👉Ask and discuss on EDAboard.com and Electro-Tech-Online.com forums.



Tell Us What You Think!! Cancel reply

You must be logged in to post a comment.

HAVE A QUESTION?

Have a technical question about an article or other engineering questions? Check out our engineering forums EDABoard.com and Electro-Tech-Online.com where you can get those questions asked and answered by your peers!


Featured Tutorials

  • PS2 Keyboard To Store Text In SD Card Using Arduino Circuit Setup On Breadboard
    How To Use PS2 Keyboard To Store Text In SD Card Using Arduino- (Part 42/49)
  • Wireless Path Tracking System Using Mouse, XBee And Arduino Circuit Setup On Breadboard
    How To Make A Wireless Path Tracking System Using Mouse, XBee And Arduino- (Part 43/49)
  • How to Make a Wireless Keyboard Using Xbee with Arduino- (Part 44/49)
  • Making Phone Call From GSM Module Using Arduino Circuit Setup On Breadboard
    How to Make Phonecall From GSM Module Using Arduino- (Part 45/49)
  • How to Make a Call using Keyboard, GSM Module and Arduino
    How To Make A Call Using Keyboard, GSM Module And Arduino- (Part 46/49)
  • Receiving SMS Using GSM Module With Arduino Prototype
    How to Receive SMS Using GSM Module with Arduino- (Part 47/49)

Stay Up To Date

Newsletter Signup

Sign up and receive our weekly newsletter for latest Tech articles, Electronics Projects, Tutorial series and other insightful tech content.

EE Training Center Classrooms

EE Classrooms

Recent Articles

  • Renesas delivers intelligent sensor solutions for IoT applications
  • Microchip Technology releases AVR-IoT Cellular Mini Development Board
  • Qualcomm acquires Cellwize to accelerate 5G adoption and spur infrastructure innovation
  • MediaTek’s chipset offers high-performance option for 5G smartphones
  • Nexperia’s new level translators support legacy and future mobile SIM cards

Most Popular

5G 555 timer circuit 8051 ai Arduino atmega16 automotive avr bluetooth dc motor display Electronic Part Electronic Parts Fujitsu ic infineontechnologies integratedcircuit Intel IoT ir lcd led maximintegratedproducts microchip microchiptechnology Microchip Technology microcontroller microcontrollers mosfet motor powermanagement Raspberry Pi remote renesaselectronics renesaselectronicscorporation Research samsung semiconductor sensor software STMicroelectronics switch Technology vishayintertechnology wireless

RSS EDABOARD.com Discussions

  • FPGA LVDS with separate clock
  • Co-simulation setup in HFSS
  • How do we test an antenna for its receiver capability?
  • highest frequency capture with arduino input capture
  • Limits of duty cycle for ICM7555 IC?

RSS Electro-Tech-Online.com Discussions

  • writing totals in Eprom
  • undefined reference header file in proteus
  • How to test phone socket?
  • ICM7555 IC duty cycle limit at high frequency?
  • intro to PI
Engineers Garage
  • Analog IC TIps
  • Connector Tips
  • DesignFast
  • EDABoard Forums
  • EE World Online
  • Electro-Tech-Online Forums
  • Microcontroller Tips
  • Power Electronic Tips
  • Sensor Tips
  • Test and Measurement Tips
  • 5G Technology World
  • About Us
  • Contact Us
  • Advertise

Copyright © 2022 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search Engineers Garage

  • Projects and Tutorials
    • Electronic Projects
      • 8051
      • Arduino
      • ARM
      • AVR
      • PIC
      • Raspberry pi
      • STM32
    • Tutorials
    • Circuit Design
    • Project Videos
    • Components
  • Articles
    • Tech Articles
    • Insight
    • Invention Stories
    • How to
    • What Is
  • News
    • Electronic Products News
    • DIY Reviews
    • Guest Post
  • Forums
    • EDABoard.com
    • Electro-Tech-Online
    • EG Forum Archive
  • Digi-Key Store
    • Cables, Wires
    • Connectors, Interconnect
    • Discrete
    • Electromechanical
    • Embedded Computers
    • Enclosures, Hardware, Office
    • Integrated Circuits (ICs)
    • Isolators
    • LED/Optoelectronics
    • Passive
    • Power, Circuit Protection
    • Programmers
    • RF, Wireless
    • Semiconductors
    • Sensors, Transducers
    • Test Products
    • Tools
  • EE Resources
    • DesignFast
    • LEAP Awards
    • Oscilloscope Product Finder
    • White Papers
    • Webinars
  • EE Learning Center
    • Design Guides
      • WiFi & the IOT Design Guide
      • Microcontrollers Design Guide
      • State of the Art Inductors Design Guide
  • Women in Engineering