Jacek Stepien

Autonomous wireless link powered with harvested heat energy

In the paper a case study of prototype wireless sensor nodes (WSN) constituting an autonomous wireless link based on ZigBee transceivers and supplied with thermoelectric generators (TEG) harvesting waste industrial heat is presented. Depending on the available power, different working scenarios of the coupled TEG and WSN are considered. Simulation data concerning estimated available electrical power as well as measurements carried out by means of a laboratory stand imitating a central heating system are presented. Design process of autonomous WSN leading to optimization of energy consumption from hardware and software sides is described.

Mobile user tracking system with ZigBee

In the paper an implementation of mobile nodes tracking system based on ZigBee and Wi-Fi wireless networks is presented. On the base of known algorithmic as well as circuit solutions a simple yet universal system, applied in prototype application dedicated for persons localization in museum premises has been developed. Since system utilizes entirely wireless communication, it can be applied in any closed objects. The system has been preliminarily verified in real in-situ environment.

The methods of broadcasting of information in ad-hoc wireless networks with mobile stations

The ad-hoc wireless networks constitute a natural way of increasing the mobility of the stations. Nevertheless, the increasing mobility of the nodes makes the realisation of multi-stage transmissions more difficult. In this paper we have reviewed the most important broadcasting methods used in mobile temporary networks. We have discussed the efficiency of these methods as it concerns the limitation of unnecessary, excessive retransmissions, as well as the minimisation of the transmission of necessary supplementary information and the tolerance of the mobility of the stations.

Electronic control unit for the tuned combustion engines with spark ignition

In this document, we have presented the structure and the functioning of the programmable controller for combustion engines with spark ignition, designed for a company executing the tuning of sports cars. In the first part, the method of connection of the computer with the target system has been presented. The second part has been dedicated to the working algorithm of the controller and the structures of data.

Time-frequency analysis of accelerometry data for seizure detection

Abstract This article presents an algorithm based on a short-time Fourier transform for reliable detection of epileptic seizures measured with three-dimensional (3D) accelerometry. The objective of the described work is to provide basic technical information to create useful alarm models for epileptic seizure detection using a mobile phone. The presented material is based on experimental measurements. Finally, the possibility of increasing smartphone detection capability by attaching a triaxial piezoelectric accelerometer to the patient’s wrist is suggested.

Proposition of the full synchronization method for transmission systems with variable duration of bits

The paper reports the problem of synchronizing clocks in the delta codecs systems with variable length of bits. The original synchronization method, valuable in systems dedicated to transmission the bits with variable time duration was projected and experimentally verified. Performed measures and observations have shown elimination of the synchronization lose phenomenon. Stand on the Spartan 3E evaluation modules, a flexible platform for the implementation the transmission system with non-uniform sampling delta codecs was developed.

Recovery synchronization in ANS-DM demodulator

Adaptive Non-uniform Sampling Delta Modulation (ANS-DM) is one of the waveform coding techniques, where a sampling instant and a quantization step size are adopted. The ANS-DM modulator produces an output binary stream, that caries information about signal and includes necessary information of coder parameters (sampling instant and quantization step). In demodulator this values have to be recovered for proper signal reconstruction. To date, no systematic investigation that considered signal decoding of the delta systems with sampling instant and step size adaptation were extensively analyzed. In the paper the analytical analysis of a parasitic signal oscillations in the reconstructed signal, as a consequence of the recovery synchronization process in ANS-DM demodulator, have been discussed. Drowned conclusions allow improving the quality of received signal transmitted over ANS-DM system in presence of noises in transmission channels.

Transmission system with variable duration of bits — Proposal of synchronization

Based on the Spartan 3E evaluation module, a flexible platform for the implementation of different algorithms for A/D conversion was created. The aim of presented work was to develop the concept of the sampling rate adaptation to the input signal rate of change in terms of practical issues including synchronization of delta codecs. The new, original synchronization method, useful in systems dedicated for transmission of variable duration of bits was proposed and experimentally verified. Performed measures and observations have shown elimination of the synchronization lose phenomenon.