Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 13 | Smartphone-based Fluorescence Microscope |
Feifan Xie Juncheng Zhou Shu Xian Lai Wentao Ni |
Xinyi Xu | design_document1.pdf final_paper1.pdf proposal1.pdf |
Wee-Liat Ong |
| # PROBLEM Microscope applications are primarily helpful in health screening and microorganisms sampling and post processing. However, most conventional microscopes are expensive (expensive lenses and imaging equipment), relatively immobile (mostly as benchtop microscopes), and require professional knowledge to operate and post process the acquired image. These restrictions pose as barriers to rural communities whom can benefit immensely from mobile microscopy technologies (clinical setup in rural areas, water sampling etc.). # SOLUTION OVERVIEW We propose a smartphone-based compound lens microscope (an external device) that is attachable to a smartphone and makes use of today’s smartphone robust camera technology. More specifically, the type of microscope we have in mind is a fluorescence microscope. We expect users to be able to attach the device to individual smartphones and capture magnified image (and store those images in their phones) up to an applicable magnification. Our current plan is to focus on sampling water to detect sewage microorganisms such as total coliforms and E. Coli bacteria for clean, potable water. The reason we chose a compound lens microscope is because double lens setup gives us a higher magnification and resolution compared to simple lens. Another benefit is the flexibility the compound lens design is capable to give which facilitates internal lens modification. The reason we decided on fluorescence microscope is because high powered LEDs are easily accessible with a relatively low cost, and still able to provide us a wide range of detectable target (bacterium, intrinsically fluorescence particles, white blood cells etc.). # DESIGN COMPONENTS - COMPOUND LENS SETUP We plan to build a compound microscope using two convex lens – one as the objective lens, and another as the eyepiece. We plan to get lens with short focal lengths (5-10mm) for our objective lens to maximize our magnification at a least possible expense of tube length increment. For the eyepiece lens, a numerically larger focal length(10-20mm) is preferred for its high efficiency on image magnification to tube-length ratio. To figure out the best lens combination and calibration, optical testing is a must-take stage. - MICROSCOPE ATTACHMENT TO SMARTPHONE Depending on the design of our microscope tube/casing, we will also need to design a device that connects our microscope to our smartphone. If our microscope takes the form of a tube, then the attachment will look more like a pair of clamps to our smartphone. If our microscope takes the form of a case, we can either directly place our phone on the casing, or also use clamps. - LED LIGHT SOURCE We will need high power, UVC LEDs (wavelength between 200-600nm depending on targets and versatility) for our sample illumination. We will need to setup a mini circuit within our microscope to mount our power supply, a microcontroller, a mechanical switch (to turn on/off the LEDs) and the LEDs as our light source. The power supply can either be dry cells, or we could use our phone as a power source. - MICROSCOPE TUBE/CASING We will need a casing that connects and covers our microscope system. We plan to draw out our design using CAD software and use a 3D printer to print the prototype out. This casing must include the design for sample holder (some space to insert thin plastic film) and the design to mount our PCB for LED illumination. Depending on how well our optical system turn out, we might also need to add some refinements to our microscope (e.g. emission filters, bigger lens etc.). A modifiable lens magnification system is considered for a more flexible use to satisfy practical requirements. # CRITERIA OF SUCCESS - MAGNIFICATION AND RESOLUTION We set our microscope to have at least a minimum of 20X magnification and resolution that is comparable to a benchtop microscope for our target applications. - COST AND PORTABILITY The design of our microscope has to be reasonably lightweight and portable because mobility is one of the most important factors of our design. The microscope should be easily attached/detached for a decent range of smartphones. We also aim to minimize the cost required for our microscope so that it is accessible to a wider group of people. - VERSATILITY/PRACTICALITY OF SAMPLED TARGETS Our microscope must aim to examine target samples that have reasonable potential for clinical usage or health applications rather than applications that are too specific. If possible, we also aim to design a microscope that can accommodate a wider range of fluorophores. - SIMPLICITY AND SAFETY OF USER EXPERIENCE AND DESIGN Because our microscope involves an external device with potentially risky sub-components (UVC LED light), the design must have careful considerations of safety (e.g. no leaking of the UV rays). The process of preparing the sample and acquiring the magnified image should also be relatively straightforward that any adult can easily learn how to operate the system. # DISTRIBUTION OF WORK Overall, the main challenge of our project revolves around setting up a working microscope model from scratch and refining it. And none of us are experts in this (not even class knowledge), therefore the early stages of design will require high level of collaboration rather than divide-and-conquer style of work. Job splitting is more likely to take form as we get into the middle stages of our project. ME FEIFAN, XIE Involves in the CAD design and practical manufacture of the microscope casing. He is responsible for compound lens system design and theoretical analysis, also lens test and calibration. ME WENTAO, NI Involves in the CAD design and practical manufacture of the microscope casing. He is also responsible for the illumination matter excitation test. EE JUNCHENG, ZHOU Responsible in post-processing and determining our image quality through data collection and comparing to standard lab microscopes. COMPE SHU XIAN, LAI Responsible for the acquiring and designing of the PCB components needed to setup LED illumination. He is also involved in compound lens system design and theoretical analysis. |
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