Executive Summary

Fluorescence Label Simulator for US Army Hydration Sensor Module (HSM)

Sponsored by: Gaia Medical Institute

Project Team:

Chianglin, James

Felsman, Kyle

Fernandez, Marina

Frausto, Michael

Lee, John­­­

 MAE 156B- Fundamental Principles of Mechanical Design II

University of California, San Diego

Dr. Jerry Tustaniwskyj

Dehydration is a serious problem seen most gravely in high-stamina or low water scenarios such as army combat desert missions or high endurance sports. One of the most dangerous qualities of dehydration is how difficult it is to detect and gauge a person’s dehydration level quickly. Gaia Medical Institute is currently developing a non-invasive saliva test that can determine different levels of dehydration using a lateral flow device similar to a pregnancy test. An emitter activates the dehydration-detecting biomarkers to create a low-intensity fluorescent light. Due to the transient nature of the fluorescent signal, the team was tasked to create a low-intensity fluorescent light simulator as well as a test bench to detect the simulated light.

The projective objective was to build a full blackout test-bed which will have a high-sensitivity photosensor and a low-intensity light-emitting diode to simulate fluorescent light. The hardware requirements of the components were:

I.       LED Simulator

a.       The LED Simulator should replicate the fluorescence of the saliva biomarker in wavelength and intensity

b.      Self-contained unit easily inserted and removed from the test bed

II.    Photosensors

a.       Two photosensors will be needed; a calibration photosensor, and testing photosensors:

                                                  i.      Calibration photosensor must be highly sensitive and monochromatic with the ability to detect specified emission wavelengths at very low-intensities.

                                                ii.      Testing photosensor must be low-cost and monochromatic with the ability to detect the intensity level of the specified emission wavelength

III. Test Bed

a.       Photosensor or LED Simulator must be mounted on a distance adjustable rack with the measurement capability and precision of 1 mm increments from 1 mm to 1 cm

b.      Minimal stray light other than LED Simulator to enter test bed

c.       Ability to swap and secure photosensor and LED Simulator

d.      Ability to hold LED Simulator in vertical and horizontal orientations

Along with the hardware requirements the group will conduct two tests; one for the distance between the photosensor and LED, and LED brightness vs. photosensor log. The tests will be assessed using the criteria of sensitivity, repeatability, signal to noise ratio, stray light performance, and temperature stability.

Figure 1 Test bed with labeled description underneath

The final design was a modular black box with variable height platforms to test different simulators, optical filters, and photosensors with very fine resolution. It was designed to be easily adaptable for future iterations of the project and throughout the final dehydration module development.

Gaia Medical Institute’s project of creating the first handheld non-invasive saliva test will help both civilian and military personnel. The device that was designed for testing will help allow testing of their saliva test strip. Although this project was in the early stages of Gaia’s project plan, ideally the test bed will be used until the end of the project cycle. The completion of the handheld dehydration testing device will help solve the problem of monitoring the dehydration level quickly in high-stamina or low water scenarios.