Lab-in-a-Phone for Smart Sensing

Abstract

Field-portable instruments for ubiquitous detection and analysis of biological, environmental and agricultural items are becoming ever more popular over their traditional non-portable benchtop counterparts as a means to ensure hazard minimization in many fields. One significantly more convenient approach that has emerged in recent years is the harnessing of smartphone capabilities to create field-deployable scientific instruments, allowing measurements to be made onsite and in real-time. In this thesis, a number of self-contained lab-in-a-phone devices have been presented with the particular focus on spectroscopic measurements. In the first work to be presented, a smartphone-based intensity fluorimeter has been developed by using the in-built white flash LED as an optical source and the CMOS camera as a detector. For spectroscopic measurements, a low-cost dispersive element fabricated by nano-imprinted technology has been added into the system within a 3D-printed enclosure to smartphone camera. By adding an optical fibre bundle, the functionality of the device was extended further to make possible spectral acquisitions from solid surfaces in hard-to-reach places. In advance to the steady-state measurements, time-resolved fluorescence intensity measurements at various temperatures is demonstrated. Finally, the utilisation of smartphone-based devices has also gone beyond chemical analysis by demonstrating a simple, low-cost, portable smartphone-based laser beam profiler. Performances of all these instruments have been analysed by some proof-of-principle demonstrations. With the IoT compatibility, the instrumentation on a smartphone can be integrated into a large network of other instruments. As such, data can be monitored, shared, and processed to build real-time regional and global maps for a range of phenomena.