Construction Of Low Cost “Smart” Microscope

Today,the demand for low-cost portable diagnostic devices has been increasing rapidly due to the public health issues.Under this trend,various types of diagnostic devices were developed using electrochemical or MEM techniques.However,as one of the most commonly used diagnostic tools,quantitative optical inspection equipment,especially optical microscope,is still missing in the market due to its large volume and high price.Therefore,how to improve the traditional microscope,reduce its size,cost and rich function becomes particularly important.Interestingly,with the rapid development of the Internet of Things(Io T)industry,the smart Io T based diagnostic tools have made great progress in the last decade.Particularly,the price of image sensors and microcontroller has dropped drastically,network transmission speed becomes fast enough for real-time operations,and high quality optical lenses below 100 RMB become available.Intrigued by these changes,we introduces an low-cost smart digital optical microscope system based on Io T framework,which can automatically perform various quantitative bioanalysis.The development of the digital optical microscope system can be divided into two parts,hardware device and software design.The hardware consists of an optical system and an electronic hardware control system.In the optical system,a low-cost smartphone lens and a long focus length CCTV camera lens are used as the objective and tube lens,respectively,giving a up to 20-fold optical magnification.Two LEDs are used for the reflection and transmission mode illuminations.The whole system was constructed using 3D printing technique.In the electronics part,a single board computer,namely Raspberry PI4 is selected for all the automation control tasks,including a voice coil motor for focusing of the objective,two step motors for sample movement and LEDs for illumination.The sample movement range reaches 20mm×20mm and the precision of the focus adjustment is at micrometer level.Along the automatic hardware,we designed a software system which can perform rapid autofocus,automatic switching of lighting mode,as well as accurate sample displacement and scanning.It allows us to conveniently link and control the system by various portable devices including mobile phones,tablets and laptops via Wi Fi.Both the back-end development and front-end development were carried out on the Raspberry Pi.In the back-end program,an image detection algorithm was developed to track and focus samples,and it solves the image stability issue faced by small microscopes.The front-end uses HTML,CSS and JavaScript to design the user interaction interface,which enables users to operate the microscope by simply opening a web page.Currently,the major specifications of the low-cost microscope are same or close to the level of the research microscopes,with its multiple illumination modes,2micrometer spatial resolution,2000 folds magnification,600×450 microns field of view,autofocus function and automatic stitching function.In combination with the low cost and ease of use of the system,we hope that in the future the system can be applied to field of clinical diagnosis and pathological analysis,providing low cost and high quality services in remote areas.