Mihaela Pantazica

Simulation of a wireless sensor network using OPNET

We aim to evaluate the performance of a ZigBee wireless sensor network using OPNET. The network is intended for a general application and should be able to collect data from many nodes, every node connected to several sensors. One possible application for such a network is in the medical area. At first the network will be used to display the evolution of blood pressure; the body temperature, the ambient temperature and pressure and the level of the transfusion liquid can be collected as well. The network coordinator will transmit the data to a local server for further processing. The simulation will be used to evaluate the general parameters of the wireless network and to optimise it.

Surface insulation resistance testing of solder pastes with protective coating

This paper presents the results obtained after performing SIR testing in order to evaluate different solder materials. The scope of the test was to determine the effects of the reflow process used and of a protective coating on surface insulation resistance (SIR) in the presence of medium heat and high humidity for several solder pastes. There were used special designed test pattern boards according to IPC-B-24 and several solder pastes with no-clean fluxes: SAC305, OM338PT, OM5300, SN100C and SN100C-XF3. After 110 hours, the measurements showed the reduced values of the average surface insulation resistance. The optical inspection did not show any electrochemical formation (dendrites) between conductors.

Multi-media “DFM” course for design of electronic modules/micro-systems

The objective of this paper is to present a multi-media Design For Manufacturing (DFM) course developed in our university and to emphasize the importance of such interactive courses in relationship with other forms of instruction as students expect today to receive more individualized training. Multi-media instruction offers multiple benefits to education, including a wide range of instructional options and, with adequate instructional design, considerable reduction of the learning time, the time of expert teachers, and when large numbers of students are involved, the cost of learning. The multi-media “DFM” course for design of electronic modules/micro-systems is part of an European project, Elect2eat (E-learning Education and Continuing Training to Electronics Assembling Technology), which is a public, multi-lingual training system [3]. Another European project, mSysTech (E-Training Microsystems Technologies), starts from this multi-media “DFM” course, being focused on the transfer of innovation in the field of micro-systems in Romania and Bulgaria. Its main objective is adapting and implementing the e-learning environment with training materials based on simulations and demonstrations to improve skills in micro-systems technology [4].

Aspects of using low layer count PCBs for embedded systems with FPGA devices in BGA packages

This paper shows part of the investigations conducted regarding the use of 2-layer printed circuit boards for embedded systems based on devices (microcontrollers or field programmable gate arrays) in BGA (Ball Grid Array) packages. Usually, the technical literature [1] recommends for applications involving programmable devices in BGA packages the use of multi-layer boards (4, 6 or more layers), but these boards are expensive for applications like educational kits or simple controls that runs at relatively low clock frequencies, around 1MHz. The paper analyzes the aspects of PCB design, manufacturing costs and technical limitations (maximum available I/O pins, signal integrity) of 2-layer printed circuit boards for a simple embedded system based on an FPGA device in 256-pin BGA package. Suitable PCB design techniques analyzed and layout recommendations are presented.

Host emulator for next generation battery chargers

A modern portable computer, netbook, smartphone or camera is powered by a smart battery. This is a device containing one or more Lithium cells, protection circuits and a power management circuit, interfaced by a two wire SMBus interface [1]. The need for higher efficiency and longer battery life has pushed the technology of the smart battery forward, for higher efficiency, smaller component count and more integrated functions controlled by internal registers. The internal registers are written and read via SMBus. A charger is evaluated by the test engineers and presented to the customers by the field application engineers on a demonstrator board which emulates the conditions found in a real system. The charger also needs a SMBus Master [2]. This paper presents a host emulator integrated in the demonstrator board, together with a Windows interface for accessing the internal registers.

Investigations on modern power supplies development based on custom PCB structures

The paper analyzes the voltage and current spikes which occur during the switching moments in modern telecommunications switching power supplies (SPS). The zero voltage switching is depicted for the full bridge converter topology with synchronous rectifier as a device under test. The novelty of the work represents the development of an automatic test platform used for creating a list of events and for measuring various parameters in SPSs.

An Experimental Investigation of Pulse Measurement by Means of a Plethysmographic Sensor Integrated in a ZigBee Medical Network

This paper aims to investigate the performance of a system consisting of plethysmographic sensors used to measure the human pulse or heart rate, and ZigBee wireless networks used to collect the data in view of processing and storing. A demo system build around a MICROCHIP development kit PICDEM Z is described. Some conclusion derived on the basis of the observations obtained during the implementation of the demo system and during the measurement campaign are given.

Comparison between two Surface Insulation Resistance tests regarding different soldering techniques

The paper shows the results of a second approach of the Surface Insulation Resistance (SIR) test performed in order to test the quality of solder pastes. The aim of the SIR test was to establish the influence of the reflow method used and of a protective coating on the SIR. At the end of this test, a comparison between the obtained results was done. Both tests were done in the conditions of environment heat and high humidity. The boards used in both experiments are special designed test pattern boards (IPC-B-24) and the no-clean solder pastes are the following: SAC305, SN100C, SN100C-XF3 OM338PT, OM5300 [1]. The measurements of the SIR values showed better results keeping in mind that this was the second experiment and that we gained experience during the first experiment.

E-learning packaging technologies course in the frame of the MSYSTECH European project

The paper presents the e-learning “Packaging Technologies” course developed in the frame of the mSysTech (E-Training Microsystems Technologies) European project. The objective of this multi-media course is to introduce the learners in microsystems packaging technologies, including design, analysis, fabrication, assembling, characterization and testing. In addition, this course will also introduce the most recent developments of micro-/nano-fabrication technologies.