On-site sensing systems provide fast and timely information about a myriad of applications ranging from chemical and biological to physical phenomena in the environment or the human body. Such systems are embedded in our daily life for detecting pollutants, monitoring health, and diagnosing diseases. Especially in the field of health care, the development of portable and affordable diagnosing systems, also known as point-of-care (PoC) devices, is a major challenge. Moreover, to this day, systems for therapeutic drug monitoring (TDM) have remained bulky and highly expensive, mostly due to the need for exceptionally precise, rapid, and highly accurate real-time on-site measurements. This dissertation focuses on the design, development, and implementation of miniaturized PoC devices for achieving high sensitivity, selectivity, and reliability through a combination of hardware and software strategies at the edge. The first part of the dissertation introduces the design of single and multi-channel electrochemical readout platforms with a high voltage range, fast scan rates, and with nano-ampere resolution, covering a broad range of electrochemical excitation techniques. These platforms were paired with electrochemical-based sensors to detect SARS‑CoV‑2, bisphenol A, and ascorbic acid. The low power feature of the proposed platforms is demonstrated by powering the complete detection system with energy harvested from natural and artificial ambient light. The second part of the dissertation introduces the design and development of a miniaturized wearable device with a pico-ampere resolution, high-speed electrochemical frequency interface, and highly stable sensing circuitry. A complete in-vivo system is demonstrated for long-term (>4 hours) measurement, wherein molecules are detected and monitored directly from a probe inserted in the subcutaneous abdomen region of a Sprague-Dawley rat. A solution for sensor drift due to biofouling and interference is demonstrated thought to the integration with real-time processing software. Furthermore, integrating the aforementioned platforms with highly reduced dense neural network models is demonstrated to increase the robustness of the sensors, allowing the detection of contaminants in complex samples, improving the sensor selectivity, and providing timely diagnoses in-situ.

Urban warfare is unfortunate reality of the modern world and that fact is unlikely to change in the near future. One significant danger to soldiers in an urban setting is posed by concealed snipers. The large amount of cover among densely packed buildings make snipers hard to detect by sight or sound. When a sniper fires at troops, it is imperative to positively locate the sniper as soon as possible to ensure the safety of soldiers in the field. One method of sniper detection is the use of distributed sensor nodes. These nodes may be stationary, mounted on a soldier or mounted on a vehicle. These nodes may accommodate many types of sensors, including microphones and cameras, both conventional and infrared. This project specifically deals with microphone arrays and conventional cameras mounted on a remote-operated vehicle. The purpose of this project is to demonstrate that mobile sensor platforms can be used alone or in groups to locate the source of gunshots as well as other sources of noise. The vehicle described is a recreational ATV. It has been outfitted with mechanical actuators and electronic control modules to allow the vehicle to be operated remotely. The selection and installation of these components is detailed. This includes the control of the ATV's steering, brakes, throttle and engine starter. The system also includes a failsafe circuit to ensure that the system will shut down if positive control is lost. An array of sensors and transducers was added to the vehicle to allow for useful data collection. This includes the aforementioned microphone array and camera. Other sensors mounted on the vehicle include a GPS antenna and an electronic compass for establishing the position and orientation of the vehicle and an accelerometer to sample engine vibration and allow for cancellation of engine noise. Once assembled, this vehicle was tested in laboratory and field environments to demonstrate its effectiveness as a mobile sensor platform. The tests showed that a microphone array could be used in combination with a camera to provide a continuous stream of images of a moving target. The test also demonstrated how a mobile acoustic node can relocate to triangulate the location of an acoustic source and thereby replicate a larger stationary network. Overall, these tests demonstrated that such a system is a feasible platform for urban combat use. Full implementation would require the fusion of several separate features, the addition of a few new features, such as semi-autonomous operation, and further field testing. / Master of Science