The document summarizes a student's seminar presentation on smoke detection systems. It describes the main types of smoke detectors, including photoelectric and ionization detectors. Photoelectric detectors are further broken down into light scattering and light obscuring types. Diagrams and descriptions of the components of each type are provided. The document also outlines the hardware used in a sample smoke detection system circuit and explains its operations, highlighting how smoke is detected by changes in light reception. Finally, it states that the circuit meets electronics standards.

1. DR. RAJENDRA GODE INSTITUTE OF
TECHNOLOGY & RESEARCH
AMRAVATI
Department of Electronics & Telecommunication
Engineering
Seminar Topic :- Smoke Detection System
Presented by:- Tejaswini R. Sawarkar
Guide:- Prof. R. M. Deshmukh
Branch :- Electronic & Telecommunication

2. Contents
 1) what is Smoke Detection System
 2) Types of Smoke Detector
 3) Photoelectric Smoke Detector
 4) Light Scattering Smoke Detector
 5) Photo Electric Smoke Detector Diagram
 6) Light Obscuring Smoke Detector
 7) Light Obscuring Smoke Detector Diagram
 8) System Hardware
 9) Ionization Smoke Detector
 10) Circuit Operations
 11) Why Smoke Detector ?

3. What is Smoke Detection System
?
 A Mechanical device that is Sensitive to smoke or particular material in the air
that transmits a signal to the measuring instrument
 Smoke detector consist of two parts
 Sensor
 Buzzer

4. Types of Smoke Detector
 Photoelectric Smoke Detector
 Ionization Smoke Detector

5. Photoelectric Smoke Detector
 The photoelectric type detector utilizes light as a detection
mechanism
 There are two types of photoelectric smoke detector
 light sensing (Scattering)
 Light obscuring (Blocking)

6. Light Scattering Smoke
Detector
 Light scattering Smoke detector depends on the ability
of small airborne particles to scatter light.
 Scattering is due to the absorption, reflection,
refraction, polarization and diffraction.
 The light emitted from the light source is not detected
by the photo sensor
 When smoke particles enter in the chamber increases,
more light is scattered towards the sensor.
 When the concentration of particles reach the
threshold, an alarm sound is produced

7. Photo Electric Smoke
Detector Diagram

8. Light Obscuring Smoke
Detector
 A projected beam can use a single light source to and
photo sensor to detect a very large area
 Most such detectors use IR-LED or laser diode as a
sensor
 Detection of smoke by attenuated light
 Uses a separate emitter and detector

9. Light Obscuring Smoke
Detector Diagram

10. System Hardware
 R1-300 ohms
 LED- white/Red
 LDR
 R3-100k potentiometer
 R2-10 kilo-ohms
 Q1-2N222,cs9013 transistor
 R4-1.2 kilo-ohms
 R5-1.2 kilo-ohms
 Speaker 8 ohm
 Q2-cs9012, any general
purpose PNP Transistor
 C2-10 nF
 C3-2.2 uF electrolytic
capacitor
 R6-1.2 kilo-ohms
 R7-5 kilo-ohm
 C1-100nF
 555 IC
 9V battery

11. Ionization Smoke Detector
 Have ionization chamber inside the detector
 Ionization is very simple two plate chamber with
voltage across along with the radioactive source of
ionization

12. Circuit Operation
The LED will light up the light dependent resistor (LDR) and
Making its resistances very low (as low as 500 ohms). In this
case, transistor Q1 and Q2are off. When there is smoke in the
area, light from LED will be blocked resulting to an increases in
LDR

13. Why Smoke Detector ?
 The circuit that is installed in the detector is up to the
standards of the electronics
 All learning techniques were implemented in the circuit