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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.

Laser Gyroscope

Team members: Darren Koh, Chiew Wen Xin

Build a laser interferometer to detect rotation.

Laser Distance Measurer

Team members: Arya Chowdhury, Liu Sijin, Jonathan Wong

Description: To build a device that uses lasers to measure distances.

(CK: We should have fast laser diodes and fast photodiodes, mounted in optics bench kits)

Alcohol Concentration Measurement

Team members: Lim Gin Joe,Sun Weijia, Yan Chengrui, Zhu Junyi

This project aims to build a sensor to measure the concentration of alcohol by optical method

(CK: you can check Optics Letters 47, 5076-5079 (2022) https://doi.org/10.1364/OL.472890 for some info)

Ultrasonic Acoustic Remote Sensing

Team member(s): Chua Rui Ming

How well can we use sound waves to survey the environment?

(CK: we have some ultrasonic transducers around 40kHz, see datasheets below)

Blood Oxygen Sensor

Team members: He Lingzi, Zhao Lubo, Zhang Ruoxi, Xu Yintong

This project aims to build a sensor to detect the oxygen concentration in the blood.

(CK: We have LEDs at 940nm and 660nm peak wavelenth emission, plus some Si photodiodes)

Terahertz Electromagnetic Wave Detection

Team members: Shizhuo Luo, Bohan Zhang

This project aims to detect Terahertz waves, especially terahertz pulses (This is because they are intense and controllable). We may try different ways like electro-optical sampling and VO2 detectors.

Optical measurement of atmospheric carbon dioxide

Team member(s): Ta Na, Cao Yuan, Qi Kaiyi, Gao Yihan, Chen Yiming

This project aims to make use of the optical properties of carbon dioxide gas to create a portable and accurate measurement device of carbon dioxide.

Photodetector with wavelength @ 780nm and 1560nm

Team members: Sunke Lan

To design photodetector as power monitor with power within 10mW.

(CK: Standard problem, we have already the respective photodiodes)

Single photon double-slit interference

Team members: Cai Shijie, Nie Huanxin, Yang Runzhi

1.Build a single photon detector using LED. The possible LED is gallium compounds based, emitting wavelength around 800nm(red light).

2. Other possible detector: photomultiplier or avalanche photon detector(do we have that?).

3.Do single double-slit interference experiment.

Other devices needed: use LED as single photon source (wavelength shorter than the emitting wavelength 800nm)

prove the detection is single photon: need optical fibre, counting module

STM32-Based IMU Attitude Estimation

Team members: Li Ding, Fan Xuting

This project utilizes an STM32 microcontroller and an MPU6050 IMU sensor to measure angular velocity and acceleration, enabling real-time attitude angle computation for motion tracking.

Hall effect magnetometer

Team members: Ni Xueqi

This project uses the Hall effect to quantify the magnitude of an external magnetic field.

Laser Scattering Air Particulate Detector

Team members: Xie Zihan，Zhao Yun，Zhang Wenbo

The primary goal of this experiment is to build a simple DIY sensor to detect and estimate the concentration of airborne particulates (like dust or smoke) using laser scattering. By measuring how much light is scattered by particles passing through a laser beam, we can observe relative changes in particulate levels in the air.

Light Sensing System Based on the Photoelectric Effect

Team members: Xu Ruizhe, Wei Heyi, Li Zerui, Ma Shunyu

This project utilizes the principle of the photoelectric effect to design a smart light sensing system. The system can detect ambient light intensity and process the data using Arduino or Raspberry Pi. When the light intensity changes beyond a predefined threshold, the system can trigger responses such as lighting up an LED, activating a buzzer, or automatically adjusting curtains.

Temperature and humidity sensors

Team members: Chen Andi, Chen Miaoge, Chen Yingnan, Fang Ye

Ultrasonic Doppler Speedometer

Team members: Yang Yuzhen,Mi Tianshuo, Liu Xueyi, Shao Shuai

1. Objective (1)Understand the principles of the ultrasonic Doppler effect and its application in speed measurement. (2)Design and build an ultrasonic Doppler speedometer to measure the velocity of a moving object. (3)Analyze experimental data and improve measurement accuracy.

2. Principle The ultrasonic Doppler effect states that when ultrasonic waves encounter a moving target (such as a small car or fluid), the frequency of the reflected wave shifts. The frequency shift $\mathrm{\Delta }f$ is related to the velocity v of the target as follows: $\mathrm{\Delta }f=\frac{2f_{0}v\cos \theta }{c}$ ，c is the speed of sound in air；$\theta$ is the angle between the wave propagation direction and the target's motion.

Resources

Books and links

• A good textbook on the Physics of Sensors is Jacob Fraden: Handbook of Mondern Sensors, Springer, ISBN 978-3-319-19302-1 or doi:10.1007/978-3-319-19303-8. There shoud be an e-book available through the NUS library at https://linc.nus.edu.sg/record=b3554643

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.

Apps

Common mobile phones these days are equipped with an amazing toolchest of sensors. There are a few apps that allow you to access them directly, and turn your phone into a powerful sensor. Here some suggestions:

• Physics Toolbox sensor suite on Google play store or Apple App store.

Data sheets

A number of components might be useful for several groups. Some common data sheets are here:

• Photodiodes:
  • Generic Silicon pin Photodiode type BPW34
  • Fast photodiodes (Silicon PIN, small area): S5971/S5972/S5973
• PT 100 Temperature sensors based on platinum wire: [[Media:|PT100_TABLA_R_T.pdfCalibration table]]
• Thermistor type B57861S (R0=10kΩ, B=3988Kelvin). Search for Steinhart-Hart equation. See Thermistor page here as well.
• Thermopile detectors:
  • G-TPCO-035 / TS418-1N426: Thermopile detector with a built-in optical bandpass filter for light around 4μm wavelength for CO₂ absorption
• Resistor color codes are explained here
• Ultrasonic detectors:
  • plastic detctor, 40 kHz, -74dB: MCUSD16P40B12RO
  • metal casing/waterproof, 48 kHz, -90dB, MCUSD14A48S09RS-30C
  • metal casing, 40 kHz, sensitivity unknown, MCUST16A40S12RO
  • metal casing/waterproof, 300kHz, may need high voltage: MCUSD13A300B09RS

Some wiki reference materials

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

Old Wiki

You can find entries to the wiki from AY2023/24 Sem 2