Angelito A. Silverio

Smart cane: Instrumentation of a quad cane with audio-feedback monitoring system for partial weight-bearing support

Proper cane handling is one of the main goals of cane therapy in the field of physical rehabilitation. Toward that goal, a system has been developed to monitor the weight-bearing performance of the patient and provide an audio feedback to affect a patients weight application onto the cane. The smart cane is designed to read the force measurement, to compare the read-out force and to generate an alert message if the force applied by the patient is incorrect. The system includes a graphical user interface, which allows real-time graphing of the force measurements and keeps a database for offline comparative data analysis by the therapist. It employs a wireless connection between the microcontroller and the computer using Bluetooth technology, which increases mobility of the patient. This will help the patient to achieve optimum rehabilitation that can lead to an improved balance in walking and eventually cane independence.

Full-wave AC-DC converter in CMOS 0.18 micron for vibration electromagnetic energy harvest

This paper presents the design and implementation of full-wave AC-DC converter in 0.18 micron CMOS technology. Five sample voltages were taken from vibration electromagnetic harvester technology (VEHT) and simulated in three operating temperatures of 0, 25, and 70 degrees Celsius. The simulation results yielded: a maximum average power efficiency of 95.02% at 0°C 95.61% at 25°C, and 91.05% at 70°C; and an average regulation percentage of 10.45% at 0°C, 24.91% at 25°C, and 10.15% at 70°C.

Development of a variable frequency impedance measuring system

In this paper, we present the design of a variable frequency AC impedance measuring system. We have implemented this into an on-board module as well as into CMOS circuitry using TSMC 0.35μm 2P4M Mixed Mode Process. The circuit consists of high output impedance “load-in-loop” Voltage-Controlled Current Source (VCCS), a high Common - Mode Rejection Ratio (CMRR) and high input impedance Instrumentation Amplifier (IA), voltage comparators, high pass filters, peak detectors, and XOR gate for phase detection. The onboard module is interfaced to a microcontroller (MCU) that is based on the Arduino platform. The MCU drives a Digital Direct Synthesis Sine Wave Generator (DDS-SWG) to generate the variable frequency input voltage that drives the VCCS.

Design of a multi-sensor readout chip for amperometric, potentiometric, impedometric, and colorimetric bio-sensor applications

Point-of-Care Testing (POCT) devices are being deployed to provide personalized healthcare monitoring or for remote monitoring whenever there is no accessible medical facility. In line with POCT, Lab-on-a Paper or Lab-on-a-Chip devices are taking flight. These include the hybrid of the sensor and readout circuit fabricated into a chip. To date, there is no single chip solution that harmonizes the four electrochemical sensing modalities which is the contribution of this work. The design of a multi-sensor readout chip is presented; this is composed of amperometric, potentiometric, impedometric, and colorimetric readout circuits implemented on TSMC 0.18 µm 1P6M technology. The chip can be used to implement a POCT to assist a patient in assessing the condition of his urinary system through urine quality indicators such as: pH value and ionic concentration of calcium (Ca2+) via potentiometric sensing; uric acid, citric acid, and calcium oxalate concentrations via amperometric sensing; osmolality or total dissolved salts through impedometric sensing; and urine turbidity, color and crystallization through its optical properties. The readout circuit designs for diversified sensing mechanisms were developed and investigated in this paper. In addition, a power savings of ∼60dB can be achieved when all the circuits of the proposed chip are disabled. The sub-circuit enable was implemented using PMOS pass transistors. Non-simultaneous sub-circuit enable both reduces the power budget and prevents the inter-sensor interference or cross-talk.

Development of a multi-frequency impedance spectrometer and photo-detector system for perovskite solar cell characterization

The developed impedance spectrometer and photo-detector system using off-the-shelf and low cost electronic components for the electrical characterization of perovskite solar cells (PSC) and assessment of its photo-electrical conversion efficiency (PCE) is presented. An electrical equivalent model is generated by curve fitting the impedance spectroscopy data, then correlating it with PCE to optimize fabrication. The system is interfaceable to a microcontroller for data acquisition and control. It consists of a Howland current source, instrumentation and transimpedance amplifiers. The system has been verified using electrical models via simulation. Fabricated PSC and their PCEs and impedance spectra are also presented.