Juan Santana

Low Power Wireless Sensor Network for Building Monitoring

A wireless sensor network is proposed for monitoring buildings to assess earthquake damage. The sensor nodes use custom-developed capacitive microelectromechanical systems strain and 3-D acceleration sensors and a low power readout application-specified integrated circuit for a battery life of up to 12 years. The strain sensors are mounted at the base of the building to measure the settlement and plastic hinge activation of the building after an earthquake. They measure periodically or on-demand from the base station. The accelerometers are mounted at every floor of the building to measure the seismic response of the building during an earthquake. They record during an earthquake event using a combination of the local acceleration data and remote triggering from the base station based on the acceleration data from multiple sensors across the building. A low power network architecture was implemented over an 802.15.4 MAC in the 900-MHz band. A custom patch antenna was designed in this frequency band to obtain robust links in real-world conditions. The modules have been validated in a full-scale laboratory setup with simulated earthquakes.

A 2.4 GHz ULP OOK Single-Chip Transceiver for Healthcare Applications

This paper describes an ultra-low power (ULP) single chip transceiver for wireless body area network (WBAN) applications. It supports on-off keying (OOK) modulation, and it operates in the 2.36-2.4 GHz medical BAN and 2.4-2.485 GHz ISM bands. It is implemented in 90 nm CMOS technology. The direct modulated transmitter transmits OOK signal with 0 dBm peak power, and it consumes 2.59 mW with 50% OOK. The transmitter front-end supports up to 10 Mbps. The transmitter digital baseband enables digital pulse-shaping to improve spectrum efficiency. The super-regenerative receiver front-end supports up to 5 Mbps with -75 dBm sensitivity. Including the digital part, the receiver consumes 715 μW at 1 Mbps data rate, oversampled at 3 MHz. At the system level the transceiver achieves PER=10 -2 at 25 meters line of site with 62.5 kbps data rate and 288 bits packet size. The transceiver is integrated in an electrocardiogram (ECG) necklace to monitor the hearts electrical property.

A 2.4GHz ULP OOK single-chip transceiver for healthcare applications

Wireless body-area networks (WBAN) are used for communication among sensor nodes operating on, in or around the human body, e.g. for healthcare purposes. In view of energy autonomy, the total energy consumption of the sensor nodes should be minimized. Because of their low complexity, a combination of the super-regenerative (SR) principle [1–3] and OOK modulation enables ultra-low power (ULP) consumption. This work presents a 2.4GHz ULP OOK singlechip transceiver for WBAN applications. A block diagram of the implemented transceiver is shown in Fig. 26.3.1. Next to the direct modulation TX [4] and SR RF [5] front-ends, this work integrates analog and digital baseband, PLL functionality and additional programmability for flexible data rates, and achieves ultra-low power consumption for the overall system.

Nano-scale resonant sensors for gas and bio detection: Expectations and challenges

It is the purpose of this paper to show expectations, challenges and initial steps concerning the realization of resonant chemical NEMS sensors able to meet the needs of future applications. Here, we focus on the functionalization principles of the sensing Self-Assembled Monolayer (SAM), modeling and simulation of CMOS-SOI resonant NEMS sensor with electrostatic actuation and MOSFET detection, first CMOS-SOI experimental results for making Si nano wire for piezoresistive detection schemes, noise limits of the resonant nano-sensors, challenges for the design of the on-chip readout circuitry, and the specific reliability issues of resonant NEMS. Some of the simulated sensitivity results of about 5 Hz/zg at 433 MHz and MOSFET detection are close to the best state- of- art experimental data from literature of 0.7 Hz/zg at 127 MHz. It is our challenge to pursuit at experimental level with our nanosensor concepts for making reliable nanodevices addressing the needs of integrated sensing.

A CAPACITIVE MEMs VERILOGA-BASED SENSOR SYSTEM FOR BUILDING INTEGRITY MONITORING

A capacitive MEMS Ultra-Low-Power readout for accelerometers and strain sensors using VerilogA models is presented. The VerilogA model of the accelerometers and strain sensors allows the simulation of a system in a half-bridge configuration. The gain of the system is controlled by integrating pulses from the excitation voltage which accurately controls the Signal-to-Noise ratio. A Figure-of-Merit of was achieved for a sensor range of ±2.0 g and ±20,000 μe over a 100 Hz bandwidth. Residual motion artefacts are also canceled by the system.

Full-scale laboratory validation of a wireless MEMS-based technology for damage assessment of concrete structures

This paper illustrates an experimental campaign conducted under laboratory conditions on a full-scale reinforced concrete three-dimensional frame instrumented with wireless sensors developed within the Memscon project. In particular it describes the assumptions which the experimental campaign was based on, the design of the structure, the laboratory setup and the results of the tests. The aim of the campaign was to validate the performance of Memscon sensing systems, consisting of wireless accelerometers and strain sensors, on a real concrete structure during construction and under an actual earthquake. Another aspect of interest was to assess the effectiveness of the full damage recognition procedure based on the data recorded by the sensors and the reliability of the Decision Support System (DSS) developed in order to provide the stakeholders recommendations for building rehabilitation and the costs of this. With these ends, a Eurocode 8 spectrum-compatible accelerogram with increasing amplitude was applied at the top of an instrumented concrete frame built in the laboratory. MEMSCON sensors were directly compared with wired instruments, based on devices available on the market and taken as references, during both construction and seismic simulation.