As said before, we went visiting Martial Geiser’s team in the HES-SO Valais to learn more about their devices (Sensor Assay Microbe Systems and LiveSense) and then went hiking in Valais villages where it is known that tap-water contains Arsenic.

Sensor Assay Microbe Systems; optical setup

LiveSense device of the team in Valais
The team in Sion works on the microfluidics device of Nina Buffi. Using the same micro-beads to concentrate the bacteria, they record the fluorescence with an optical fiber. A laser serves as light source and lighten the sample at an angle of 40°.
We learned a lot about optics and how to improve Prototype II. In our prototypes, we used the LEDs without testing if they really emit at the right wavelength, and same for the filters, so it would be better to test that. We were advised to use lenses in Prototype II, in order to focalise the light and be sure it is filtered correctly.
The team was very nice and received us very well, we learned a lot of passionating things over there.
After that, we took the train to Martigny and then to Vernayaz to begin our walk in the research of contaminated tap-water.