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Computer Microscope to test drinking water

Convert a customer grade web cam into a microscope to be used with your computer to analyse water if it is drinkable.


Project sponsored by FabLab Luzern,

original project page:  (in German)

Authors: Emika Märki, Ruedi Stirnimann, Urs Gaudenz. 


The natural disaster in Japan has shaken us all. Within a few hours, future plans and prospects have been destroyed by thousands of people. The technology allows us to develop leading-edge equipment, which should help us to prevent such occurrences. But sometimes they do not work. Million of funds were invested in research and development of devices, and yet they have failed at the crucial moment. The death of several thousand people was the result. But that's not all - the people who escaped the tragedy, must now find a way to find the everyday life back.

Water is a key element since the dawn of life on Earth however, its ingestion of contaminated water, which is caused by natural disasters, for example, can cause considerable damage and disease. The pathogens are usually bacteria or viruses. They solve, for example, salmonella, meningitis, hepatitis A, cholera and polio of .1

There is therefore no coincidence that people need clean water for survival. Therefore, access to clean water is a basic prerequisite of human civilization. It is important to the people tools to make available to determine a simple and inexpensive way the purity of water. Viruses and bacteria are microorganisms that are not visible to the naked eye. To see if water is contaminated biologically, we need optical Gerätschaften.Es is so that such optical devices are often very expensive. The population in the places that have suffered from poor water quality, but not the income or capital available to afford such devices. The aim of this project is to develop a microscope that provides at a low cost, a sufficient optical magnification at a suitable image quality.

"Many small people in many small places doing many small things that will change the countenance of this world." 
Proverb of the Xhosa (Tanzania, South Africa, Botswana and Lesotho)

Genesis of the idea

The idea of ​​a conventional computer camera (webcam) without additional optics in a simple and inexpensive to transform microscope was developed in collaboration between scientists and artists in a workshop. The idea was further pursued in the "International Society Hackteria" directed by Marc Dusseiller and published. On competition "Little Life Savers" was the first time through the "mini-scope DIY Kit" developed and produced in small series.Due to the small number of parts and easy assembly can now who wants to build a cheap computer microscope itself.

The first version of the kit, the "mini scope - Stage" could be produced with a very small number of parts, and served first experiments and experiments with a microscope kit. The design was then in FabLab with support from the Yurt Fabmanagers novel developed and improved. The submitted version of "mini scope - puzzle" can be achieved without the screw and is completely assembled and are dust-proof complete. In addition, even a DIY slide with a defined interior volume and a brightness control to come to the light.

Application of the Mini Scopes

The goal is to use the mini scopes within minutes of drinking water due to its biological water quality to determine and distinguish whether the content of this water sample is immediately drinkable or not.

If contamination of the water by organic substances to form characteristic communities (biological community) with typical Leitorganismen, which are suitable as indicators for assessing water quality premium2. These form the basis of Saprobiensystems (Sapros = decomposition, bios = life), which allows us to water in various stages of clean water (potable) water with dirt and to divide (not drinkable). It should be noted, however, that no single index forms, but the respective Gesamtbiozönose is crucial. For us as a layman, it is biology, but almost impossible to detect and accurately classify biological communities in different classes.Therefore we limit ourselves to two levels: clean water and dirty water. Using Water Cards (see Figure 1) can be performed by the user of the mini-site Scopes any provision of drinking water quality (potable / non potable).

Technical Requirements

It is possible to achieve by simple modifications to a webcam, a magnification effect. In the course of this project will examine whether this increase is sufficient to identify the water occurring microorganisms. Also to be examined how such a camera - microscope can be produced at competitive prices. To use it in environments where the population has not dissipated over budget. It is important when the design is that the microscope is not operated by trained personnel. It use to be simple and be easy or even impossible to maintain. The microorganisms must be recognized by laymen. It should be available in a way that lay people can operate in different language areas of the microscope without difficulty.

Since the mini scope will not come in exactly specifiable operating environments, the construction possible, use a water-and dust-proof housing may have. It is also desirable when the microscope has a built-in lighting, as the daylight for the detection of microorganisms is not enough sometimes.


The impetus for this project came from the realization that Webcams are very inexpensive, but wear out quickly. A repair is not worthwhile, so the cameras end up in the trash after a short time. However, this need not be. Lenses can create based on their concave or convex shape using an optical imaging of light influence. Whether in a webcam or a microscope - the operating principle remains the same.

The three keywords of the mini-scopes are simple, safe and inexpensive. The construction of the mini scope is simple, the assembly resembles a Legokonstruktion3 that can be put together part by part, without tools. In addition, the electronics inside the mini scope is safely stored, so that may have external factors, such as dirt particles, no influence. The mini scope is particularly suitable for field tests, as he transported easily due to its ergonomic shape and durable and has a very simple application. The material is inexpensive and available in any hardware store. The mini scope can be built quickly and easily and is cost effective because the camera costs only 25 CHF.


The basic idea was born after the Umweltkatastophe in Japan, as the drinking water was scarce, and were inundated large areas of arable land and grain. We have developed a simple device kit and adapt a system that allows it to perform in a short time, a biological analysis of water, so that potable water can be identified. It would be interesting to extend this system to Japan, so it can identify after the tsunami disaster in schools or by private drinking water with simple means. This assumes that the saprobic system is adapted to living conditions in Japan and to ensure that organisms can act as a lead nature. In addition, a program can be developed, that the identification of the biological community performs accurately, so that even a layman is able to split water into different classes (according to the classification of Kolkwitz and Marsson).

A prototype of the "mini scope Stage" was on 22Submitted in April 2011 and exhibited at the Luga FabLab Lucerne. 
A prototype of the "mini scope puzzle" was on 31 May 2011 FabLab submitted along with documentation.

The complete documentation with photos is as Word and PDF file before. 
The kit is released under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 Switzerland License.


Emika Maerki

  • Industrial engineer at 2.Sem HSLU T & A
  • Trained Pharmaceutical Biology Laboratory Technician
  • Project management, documentation, construction
  • emika.maerki @

Ruedi Stirnimann

  • 2nd Industrial Engineering Sem HSLU at T & A
  • Experimental design, determination of the magnification, electronics
  • ruedi.stirnimann @

Urs Gaudenz 
Lecturer in product innovation, HSLU T & A

  • Mitt Board member International Society Hackteria,
  • Project assignment, documentation, prototype construction
  • urs.gaudenz @


Instructions Miniscope

Camera modification

The core piece of the microscope will form a commercial webcam. In this case, the webcam must be dismantled.When thus exposed electronics and optics is now to the camera lens can be unscrewed. To unscrew the lens is now reversed so screwed onto the camera sensor, the electronics again. It is important to ensure that no dirt gets in the transformation into the lens. This modified camera provides magnification images now instead of the previous video at medium range.

Cable modification

From the USB port of a computer or laptop, the entire electricity needs of the microscope is covered. Since the illumination of the sample container is not of the camera module is done, must be picked up with the USB cable to the supply of additional lighting. The voltage of a standard USB port is 5V with a maximum current of 100mA.

The USB cable can be run with four cores. Each of the strands in the USB cable is sheathed with a differently colored insulation. The 5V supply is transmitted with a red insulated wire and the reference potential is taken with a black lace. So the need for care in the red and black wire at one point leading away from the insulation and a wire are soldered. The newly modified camera module and cable can be installed in a suitable housing.

Body parts kit

The housing consists of 12 individual acrylic glass parts

2 side panels 
2 supports 
2 guide rails 
1 camera plate 
1 rear panel 
1 front panel 
1 Cover plate 
1 base 
1 Focus screw head 
In addition, in kit: 2 slides made of acrylic glass, with 700 mm3 injection volume

Assembly Miniscope

1st Camera module mounted on board camera. 
2nd Potentiometer on plate cover stick. 
3rd Resistance to solder the potentiometer. 
4th Props and camera plate combined with the rear wall. 
5th Side walls, front and rear panels put together. 
6th Walls are positioned on the base plate and camera cable. 
7th Wall plug in the base plate. 
8th Connecting wires for LED through cover plate. 
9th Focus Fokusschrau screw-tighten screw head. 
10th Camera plate and cover plate to sit down with focus adjustment. 
11th Cover plate to press it into place. 
12th Install guide rails. 
13th LED design (model: wire & shrink tubing) attached.

1st June 2011 by Gaudi.