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There exists a strong correlation between the pH levels of the gastrointestinal (GI) tract and GI diseases such as inflammatory bowel disease (IBS), ulcerative colitis, and pancreatis. Existing methods for diagnosing many GI diseases predominantly rely on invasive, expensive, and time-consuming techniques such as colonoscopy and endoscopy. In this study, an autonomous ingestible smart biosensing system in a pill format with integrated pH sensors is reported. The smart sensing pills will measure the pH profile as they transit through the GI tract. The data is then downloaded from the pills after they are collected from the feces. The sensor is based on electrodeposited PANI on carbon-coated conductive threads providing high pH sensitivity. Engineering innovations allowed integration of thread-based sensors on 3D-printed pill surfaces with front-end readout electronics, memory, and microcontroller assembled on mm-size circular printed circuit boards. The entire smart sensing pill possesses an overall length of 22.1 mm and an outer diameter of 9 mm. The modular biosensing system allows integration of thread-based biosensors to monitor other biomarkers in GI tract that mitigates the complex sensor fabrication process as well as overall pill assembly. [ABSTRACT FROM AUTHOR]

There is a need to develop cost-effective and compact solutions for Smart Home monitoring. Existing monitoring systems depend on continuous power sources to support the operation of sensors and electronics modules used therein. In this article, we present three simple battery-free, Radio-Frequency Identification (RFID)-based solutions for real-time monitoring of the orientation of an object using a tilt sensor based on a metallic bead, an entry detection system utilizing a reed switch-based proximity sensor, and a temperature crossing event detection using a thermistor. All sensors are integrated with individual passive RFID tags. The proposed sensing mechanisms were also combined to achieve multi-modal logic sensing operation. Active events (change in position, motion, and temperature) would alter the state of the corresponding flexible RFID sensors to transmit warning signals wirelessly to an RFID reader, realizing a simple RFID-based Smart Home network. The proposed platform has been validated through extensive simulation and actual measurements. [ABSTRACT FROM AUTHOR]

In this article, we present a magnetically–tunable quad–band filter with high tunability in the frequency range of 2.1–3.9 GHz. A multi–band filter with four stop–bands comprises of a microstrip line coupled to four frequency–selective split–ring resonators (SRRs). We achieve tuning of individual frequency bands using magnetic reed switches connected in between the capacitive gaps of each split–ring resonator. Application of magnetic field tunes this capacitance affecting its resonance frequency. The measured reflection spectrum of the proposed device matches well with the simulation results. The results show more than 25% tunability for each of the four bands with bandwidth values in the range of 30–70 MHz with over 100% overall tunability in the 2.1–3.9 GHz frequency spectrum. [ABSTRACT FROM AUTHOR]