Smoke detection in air: Difference between revisions

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== Lock-In Amplifier ==
== Lock-In Amplifier ==
Measure small signals in a large background (huge noise).
Measure small signals in a large background (huge noise).


[[File:SMOKE1.png|400px|center]]
[[File:SMOKE1.png|400px|center]]


=== Mathematical Description ===
=== Mathematical Description ===
[[File:SMOKE2.png|500px]][[File:SMOKE3.png|500px]]
[[File:SMOKE2.png|500px]][[File:SMOKE3.png|500px]]


=== Signal Process ===
=== Signal Process ===
[[File:SMOKE4.png|500px|center]]
[[File:SMOKE4.png|500px|center]]


=== Logic Flow ===
=== Logic Flow ===
Line 22: Line 26:
== Experiment ==
== Experiment ==
We can divide this experimental setup into two parts: the first part will detect the scattering light in the air, and the second part will amplify such signal.
We can divide this experimental setup into two parts: the first part will detect the scattering light in the air, and the second part will amplify such signal.


=== Component List ===
=== Component List ===
Line 31: Line 36:
: 6)  Resistor (1.2K)
: 6)  Resistor (1.2K)
: 7)  LED (Green)
: 7)  LED (Green)


=== Schematics ===
=== Schematics ===
[[File:SMOKE10.png|1200px|center]]
[[File:SMOKE10.png|1200px|center]]


=== Detection Setup ===
=== Detection Setup ===
[[File:SMOKE_SETUP.jpg|800px|center]]
[[File:SMOKE_SETUP.jpg|800px|center]]
In this part, we use BWP34 Silicon PIN Photodiode as the detector. Here the capacitor and resistor are used to protect the photodiode.
In this part, we use BWP34 Silicon PIN Photodiode as the detector. Here the capacitor and resistor are used to protect the photodiode.


=== Lock-In Amplifier Setup ===
=== Lock-In Amplifier Setup ===
[[File:LOCKIN1.jpg|600px]] [[File:LOCKIN2.jpg|600px]]
[[File:LOCKIN1.jpg|600px]] [[File:LOCKIN2.jpg|600px]]
[[File:LOCKIN3.jpg|600px]] [[File:LOCKIN4.jpg|600px]]
[[File:LOCKIN3.jpg|600px]] [[File:LOCKIN4.jpg|600px]]


=== Video ===
=== Video ===
In this video, we have recorded the voltage change in the lock-in amplifier under the situation when the smoke (vaporised tin) gradually drifts in, maintains and finally disappears.
In this video, we have recorded the voltage change in the lock-in amplifier under the situation when the smoke (vaporised tin) gradually drifts in, maintains and finally disappears.
<p>[[Media:SMOKE_VIDEO.mp4]]<p/>
<p>[[Media:SMOKE_VIDEO.mp4]]<p/>


=== Data Plot ===
=== Data Plot ===
[[File:SMOKE11.png|1200px|center]]
[[File:SMOKE11.png|1200px|center]]


=== Error Analysis ===
=== Error Analysis ===


== Further Discussion ==
== Further Discussion ==


== Reference ==
== Reference ==
Error Analysis in Experimental Physical Science: https://faraday.physics.utoronto.ca/PVB/Harrison/ErrorAnalysis/ErrorInMean.html
Error Analysis in Experimental Physical Science: https://faraday.physics.utoronto.ca/PVB/Harrison/ErrorAnalysis/ErrorInMean.html

Revision as of 15:00, 28 April 2022

Introduction

Smoke detector is a device that senses smoke, typically as an indicator of fire. Commercial smoke detectors issue a signal to a fire alarm control panel as part of a fire alarm system. Household smoke detectors, also known as smoke alarms, generally issue an audible or visual alarm from the detector itself or several detectors if there are multiple devices interlinked [1].


Lock-In Amplifier

Measure small signals in a large background (huge noise).



Mathematical Description


Signal Process


Logic Flow


Experiment

We can divide this experimental setup into two parts: the first part will detect the scattering light in the air, and the second part will amplify such signal.


Component List

1) DC Voltage source (MATRIX MODEL: MPS-3005L-3)
2) MODEL SR830 DSP Lock-In Amplifier
3) BWP34 Silicon PIN Photodiode
4) WAVESURFER 104MXS Oscillator
5) Capacitor (50V 22uF)
6) Resistor (1.2K)
7) LED (Green)


Schematics


Detection Setup

In this part, we use BWP34 Silicon PIN Photodiode as the detector. Here the capacitor and resistor are used to protect the photodiode.


Lock-In Amplifier Setup


Video

In this video, we have recorded the voltage change in the lock-in amplifier under the situation when the smoke (vaporised tin) gradually drifts in, maintains and finally disappears.

Media:SMOKE_VIDEO.mp4

Data Plot


Error Analysis

Further Discussion

Reference

Error Analysis in Experimental Physical Science: https://faraday.physics.utoronto.ca/PVB/Harrison/ErrorAnalysis/ErrorInMean.html