Dept of Electronic & Computer Engineering

Remote pressure monitoring is of particular importance in medical and environmental applications as it is less labour intensive, safer and offers peace of mind to the general public. To meet this demand, a prototype system has been developed and used to evaluate thick-film pressure sensors with an oxide dielectric layer. The circuit is based on the principle of capacitance-frequency-voltage conversion and has been designed to minimize power consumption. Each device was tested under hydrostatic pressure in the range 0-17 kPa and assessed in terms of sensitivity, hysteresis, repeatability, creep and temperature effects. The results show that this approach may be used for the fabrication of cost effective, reliable devices for wireless pressure sensing applications.

This paper presents the use of Xilinx ChipScope Pro integrated logic analyzer for Field programmable gate arrays (FPGA) as a board-and system-level diagnostic tool. FPGA designs have become increasingly dense and complex. They are difficult to debug because more and more of the relevant signals are buried deep within the logic fabric. Access to signals in the FPGA, on board or in the system is very restricted whether troubleshooting is done in the lab or in the field. The Xilinx ChipScope™ Pro integrated logic analyzer has solved much of the problem at the FPGA level. In this work, ChipScope TM has been used to test and verify a developed system that presents the digital core of a wireless sensor module and it has been implemented in (Spartan 3) based FPGA development board.

This paper presents a review of developed simulated models for a wireless data acquisition system. The system reads analogue information provided by two sensors used for medical purposes. The real data have been recorded by two, pH and pressure sensors used in diagnosing conditions of the esophagus that are employed to examine the system performance. The created model contains four main simulated units using SIMULINK. The first unit contains the output signal, which is encoded to digital signal based on adapting one of the pulse coding modulation (PCM) algorithms. The second unit simulates the processor function that is responsible for framing, mixing and compressing the incoming bit streams from both sensors. The third unit, where the digital data are modulated and sent through different noisy channels, represents an efficient FSK transmitter/receiver model. At the receiver end, the signal is demodulated and processed inversely to extract the original analogue signal read by the two sensors.

The aim of this study is to model and design an efficient wireless system that should be easy to integrate with other technologies or infrastructures at a low cost. The system is reading analog information recorded by a biomedical sensor in a transmitting unit attached to the patient. The recorded data is converted digitally using ADC and sent to FSK transmitter through FPGA. Verilog HDL has been used to implement the required functions of the FPGA. SIMULINK  software has been used to model and simulate Frequency-Shift Keying (FSK) Transmitter/ Receiver suitable for short-range communications. A two-tone FSK signal is generated, passed through a noisy channel, down converted to baseband and passed to FM detector to restore the original transmitted bit stream. The behavioral HDL design has been interfaced to the SIMULINK model and the overall performance has been verified.

This paper presents a novel simulated model for a wireless data acquisition system. The system will read analogue information provided by two sensors and can be used for medical purposes. Real data has been obtained and a simulation of the two signals coming from both pH and pressure sensors embedded in the system has been employed. The created model contains four main units simulated using SIMULINK. At the first unit, the output signal is encoded to digital signal based on adapting one of the Pulse Coding Modulation (PCM) algorithms. The second unit simulates the processor function that is responsible for framing, mixing and compressing the incoming hit streams from both sensors. The third unit, where the digital data is modulated and sent through different noisy channels, represents an efficient FSK transmittertreceiver model. At the receiver end, the signal is demodulated and processed inversely to extract the original analogue signal read by the two sensors.

In this work, a design of wireless system for multisensors monitoring has been presented. The main purpose of this research is to develop an efficient telemetry system for measuring water pressure and temperature signals. The system reads data from two types of sensors, resistive and capacitive. Anderson circuit configuration has been used for the resistive sensor, since it offers linear like behavior. The capacitive interface is based on capacitance-frequency-voltage conversion that uses phase lock loop (PLL) to convert the frequency to voltage. A developed pressure sensors based on polyvinylidene fluoride (PVDF) was used to evaluate the performance of the capacitive interface. Two mechanisms have been adopted to reduce the overall power consumption. These are power scheduling and wakeup circuit for the capacitive interface. The first one is implemented fully by the micro-controller unit (MCU) in order to switch on/off all the system units. A wakeup circuit has been designed to interrupt the MCU when it is in the sleep mode and the capacitive samples are changing significantly. A platform for wireless sensor network (WSN) has been developed so that the receiver side can communicate with more than one sensor node.

In this work, a design of wireless system for multi-sensors monitoring has been presented. The main purpose of this research is to develop an efficient telemetry system for measuring water pressure and temperature signals. The system reads data from two types of sensors, temperature (resistive) and pressure (capacitive). Anderson circuit configuration has been used for the resistive sensor, since it offers linear like behavior. The capacitive interface is based on capacitance-frequency-voltage conversion that uses phase lock loop to convert the frequency to voltage. A developed pressure sensors based on polyethylene and polyvinylidene fluoride, were used to evaluate the performance of the capacitive interface. A small size wireless module has been built separately to test the capacitive interface for a certain range of pressure. Two mechanisms have been adopted to reduce the overall power consumption. These are power scheduling and wakeup circuit for the capacitive interface. The first one is implemented fully by the micro-controller unit (MCU) in order to switch on/off all the system units. A wakeup circuit has been designed to interrupt the MCU when it is in the sleep mode and the capacitive samples are changing significantly. A platform for wireless sensor network (WSN) has been developed so that the receiver side can communicate with more than one sensor node.

Field programmable gate arrays (FPGAs) play many important roles, ranging from small glue logic replacement to System-on-Chip designs. Nevertheless, FPGA vendors can not accurately specify the energy consumption information of their products on the device data sheets because the energy consumption of FPGAs is strongly dependent on target circuit including resource utilization, logic partitioning, mapping, placement and route. While major CAD tools have started to report average power consumption under given transition activities, energy optimal FPGA design demands more detailed energy estimation.

In this paper, The radio Frequency (RF) Monitoring and Measurement of the Environmental Research Institute (ERI) located in Cork city will be monitored and analyzed in both the Zigbee (2.44 GHz) and the industrial, scientific and medical (ISM 433MHz). The main objective of this survey is to confirm what the noise and interferences threat signals exist in these bands. It was agreed that the surveys would be carried out in 5 different rooms and areas that are candidates for the Wireless Sensors deployments. Based on the carried on study, A Zigbee standard Wireless Sensor Network (WSN) will be developed employing a number of motes for sensing number of signals like temperature, light and humidity beside the RSSI and battery voltage monitoring. Such system will be used later on to control and improve indoor building climate at reduced costs, remove the need for cabling and both installation and operational costs are significantly reduced.

In this paper, a miniaturized, low power, bidirectional wireless communication system has been developed to be used for in vivo pressure monitoring. The system prototype consists of miniature FSK transceiver integrated with Microcontroller unit (MCU) in one small package, chip antenna, and capacitive interface circuitry based on Deltasigma (XA) modulator. At the base station side, the same transceiver chip is communicating with a PC through a graphical user interface (GUI) to either sends/receives commands/data. Industrial, Scientific and Medical (ISM) band RF (433 MHz) was used to achieve half duplex communication between the two sides. A digital filtering has been used in the capacitive interface to reduce noise effects forming capacitance to digital converter (CDC). All the modules of the mixed signal system are integrated in a printed circuit board (PCB) of size 22.46x20.168mm.

The aim of this study is to design and develop a wireless sensor system integrating 24 bits analog to digital converter (ADC) and long range RF transceiver unit. The system is reading from two types of sensors, pressure and temperature. The serial communication between the ADC unit and RF transceiver is controlled by Spartan-3 FPGA device. A number of tasks are implemented by the FPGA device like interfacing, buffering and compression. A capacitive interface circuit has been employed for the pressure sensors and it is based on the principle of capacitance-frequency-voltage conversion. The RF transmitter is communicating with the FGPA through handshaking protocol and sending the data through ISM band. The pressure data will be compressed to avoid sending any repeated values aiming further reduction in the power consumption.

A prototype of miniaturized, low power, bidirectional wireless communication system was designed for in vivo pressure monitoring. The capacitive pressure sensors have been developed particularly for the medical field, where packaging size and minimization of the power requirements of the sensors are the major drivers. The pressure sensors have been fabricated using a 2.4 µm thick strain compensated heavily boron doped SiGeB. In order to integrate the sensors with the wireless module, the sensor dice was wire bonded onto TO package using chip on board (COB) technology. The telemetric link and its capabilities to send information have been examined on a test bench. A full pressure range from 0 to 10kPa was generated using either air or water pressure pumped through connected tubes to simulate the environment similar to the one inside the gastro Intestinal (GI) tract.

In this paper, a wireless sensor network mote hardware design and implementation are introduced for building deployment application. The core of the mote design is based on the 8 bit AVR microcontroller, Atmega1281 and 2.4 GHz wireless communication chip, CC2420. The module PCB fabrication is using the stackable technology providing powerful configuration capability. Three main layers of size 25 mm2 are structured to form the mote; these are RF, sensor and power layers.

A novel cost-effective real-time gamma radiation monitoring system based on metal oxide thick films was designed and tested. The changes in capacitances of ZnO and SnO 2 thick film capacitors with interdigitated electrodes were monitored in real time under the influence of gamma radiation using miniaturized, low power, bi-directional wireless communication system. The capacitive interface circuitry was based on a Delta-sigma (ΣΔ) modulator using switched capacitor (SC) circuit architecture with integrated on-chip temperature sensor. At the base station side, an Frequency Shift Keying (FSK) receiver/transmitter is connected to another MCU unit, which send the received data or received instructions from a PC through a graphical user interface GUI. Industrial, Scientific and Medical (ISM) band RF (433 MHz) was used to achieve half duplex communication between the two sides. All the modules of the mixed signal system are integrated in a printed circuit board (PCB) of size 22.46x20.168mm. The overall system supply voltage is 2.7V maximum. 137 Cs source with an activity of 370 kBq was used. An increase in the values of capacitance with radiation was recorded for both films to a certain dose level, determined by the material of sensitive layer.

The aim of this study is to design and develop a wireless sensor system integrating 24 bits analog to digital converter (ADC) and long range RF transceiver unit. The system is reading from two types of sensors, pressure and temperature. The serial communication between the ADC unit and RF transceiver is controlled by Spartan-3 FPGA device. A number of tasks are implemented by the FPGA device like interfacing, buffering and compression. A capacitive interface circuit has been employed for the pressure sensors and it is based on the principle of capacitance-frequency-voltage conversion. The RF transmitter is communicating with the FGPA through handshaking protocol and sending the data through ISM band. The pressure data will be compressed to avoid sending any repeated values aiming further reduction in the power consumption.

The study in this paper is focused on the improvement of a Field Programmable Gate Arrays (FPGA) based design using a hierarchical analysis tool offered by XILINX PlanAhead'TM. During this work, PlanAhead software is used to address any problems on the physical side of our FPGA design flow in order to add more visibility and control.