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Welcome to the wiki page for the course PC5271: Physics of Sensors!

This is the repository where projects are documented. Creation of new accounts have now been blocked,and editing/creating pages is enabled. If you need an account, please contact Christian.

Projects

Project 1 (Example)

Keep a very brief description of a project or even a suggestion here, and perhaps the names of the team members, or who to contact if there is interest to join. Once the project has stabilized, keep stuff in the project page linked by the headline.

Simple Optical Heart Rate Monitor

This project demonstrates the principles of photoplethysmography (PPG) through the construction of a simple device to measure heart rate. The project involves using an LED and photodiode to detect variations in light absorption caused by changes in blood volume during each heartbeat.

Gas sensor

This project aims to use high and low detection methods of tin dioxide (SnO2) sensor to detect carbon monoxide or other combustible gases.

Optical Sensor for Noise Flickering

Group Members: Eric Cheung; Lee An Min, Amanda; Loh Jia Ying Whitney

This project aims to use a simple voltage divider made up with resistors and LDR to measure visual noise tags.

Real time temperature alarm

This project aims to build a system using Python and Raspberry Pi to measure and display temperature in real-time using temperature sensors, and to issue an alarm when the temperature exceeds the set threshold

Gravitational Torsion Balance

This project aims to determine the gravitational constant using the gravitational torsion balance based on the Cavendish Experiment

Resources

Devices and material

Apart form the stuff in the teaching lab, we have a resources you may want to consider for your project:

• ...

Software

• Various Python extensions. Python is a very powerful free programming language that runs on just about any computer platform. It is open source and completely free.
• Gnuplot: A free and very mature data display tool that works on just about any platform used that produces excellent publication-grade eps and pdf figures. Can be also used in scripts. Open source and completely free.
• Matlab: Very common, good toolset also for formal mathematics, good graphics. Expensive. We may have a site license, but I am not sure how painful it is for us to get a license for this course. Ask if interested.
• Mathematica: More common among theroetical physicists, very good in formal maths, now with better numerics. Graphs are ok but can be a pain to make looking good. As with Matlab, we do have a campus license. Ask if interested.

Some wiki reference materials

• MediaWiki FAQ
• Writing mathematical expressions
• Uploading images and files

Project : (Position Sensor)

• Group Members: Angela Anna Baiju, Chenyue Gu, Joel K Jose

Abstract

Using PDH technique to sense the vibration and the movement of the mirror driven by the noise from the environment (acoustic, thermal, etc.)

PDH is commonly used in locking to provide a means to control and decrease the laser’s linewidth, and further to stabilize the mode of the laser light. Alternatively, if a stable laser is available, the PDH technique can be used to stabilize and/or measure the instabilities in an optical cavity length.

In this proposal, we will lock the cavity by reading the error signal of reflection/transmission of the cavity and then feed it back to the input mirror, moving the mirror with a PZT. And then we can read out the cavity length change from the error signal. This sensing technique is commonly using in LVK (LIGO-Virgo-KAGRA) interferometric gravitational wave detection community, as well as quantum optomechnics.