In recent years, the consumption of multimedia content on the Internet has increased substantially. However, there are devices without Internet access that would be interesting if they could play this content, such as loudspeakers. It would also add value if it were a low-resource device, which would have a direct impact on its cost. This TFG aimed to design and implement a network of low-resources wireless nodes for the reception, decoding and playback of MP3 audio within a multipoint communications network.

This work continued the development of the system carried out in a previous TFG, which is described on this post. The system consisted of a transmitter located into a computer and several receivers, each one of them located into a esp8266 chip. The transmitter sent codified audio to a multicast direction, which could be received the receptor chips connected to his same Wi-Fi network, to be decoded and reproduced.

The first objective was to improve the reproduction audio quality of the system. To achieve this, a MP3 decoder chip module was integrated to work as a slave system controlled by the esp8266. After that, audio tests were then carried out to check the similarity between sent and received audio.

The second objective was to provide configurability to the system. A software tool was developed, which set the esp8266 as an access point. If the user connected to it, a configuration website was deployed. This site had a form where the user may write the SSID and the password of a Wi-Fi network. After that, the esp8266 connected to that Wi-Fi network, and started the codified audio reception.

The last objective of this TFG was the design and the implementation of a hardware prototype of the node which included the two modules. For this purpose, a printed circuit board has been designed and manufactured, consisting of the necessary elements to connect all the modules of the system. The resulting PCB and the the final version of the node, connected with the esp8266, can be seen in the pictures below.

When you Look At This, then you will understand that the augmentation in the number of risk situations and accidents has caused an increase in the number of spinal cord injuries. It is not very complicated to consult car injury lawyers for Chinese speakers if you are from china . Hence, you need get panic. These injuries cause plexias and paralysis of the different members of the affected person. This problem has made it necessary to start looking for possible therapies to enhance the lives of patients. One of these solutions is Functional Electrical Stimulation (FES). FES is a technique based on the use of electrical stimulation of the motor nerves in order to generate a functional movement such as walking or picking up an object. This technique involves a series of stimulation parameters that are necessary to control: the stimulation amplitude, the stimulation frequency, the pulse width that composes the stimulation pattern and the waveform of the signal. The objective of this End-of-Degree Project was the development of a platform that allows the electrical stimulation of the motor nerves and the control of the stimulation parameters.

The device designed in this project is constituted by a hardware part and a software part. The stimulator is composed of a series of modules: amplifier module, signal generation module and human-device interface. The signal generation module allows us to control the stimulation parameters through the designed software. Additionally, it is necessary to design an amplification module so that the signals generated have the voltage and current levels necessary for stimulation. The power supply module is responsible for the power supply of the amplifier module and the signal generation module. The interface between the device and the user is based on surface electrodes connected to the output of the amplifier module. The different modules and their components are implemented on a printed circuit board (PCB) that will support and join the modules.

The future of functional electrical stimulation is the creation of closed systems to control the stimulation parameters according to the position of the muscles. Two possible routes can be taken: the use of sensors such as accelerometers and the creation of brain-personal interfaces.

Massive and rapidly increasing use of wireless devices is raising concerns about eventual saturation of the available spectrum in wireless communications, known as the spectrum scarcity problem. This issue is especially relevant for power- and resource-constrained devices, even more when considering the largely variable and adverse environmental conditions radio channels are usually subject to.  Considering the case of a network of sensor nodes, a smart approach to face this problem is the use of Cognitive Wireless Sensor Networks (CWSNs), which consist in networks capable of modifying their communication parameters depending on the environmental conditions.

One of the ongoing research lines of the B105 Electronic Systems Lab focuses on the development of low-power CWSNs by designing sensor nodes using a Software-Defined Radio system (SDR). Specifically, an architecture based on the Atmel AT86RF215 transceiver and the SmartFusion2 System-on-Chip (SoC) is used to carry out certain cognitive tasks.

The specific objective of this project was to implement communication between the aforementioned elements and a personal computer (PC). To achieve that, a Printed Circuit Board (PCB) was developed to serve as an interface platform between the different hardware elements in the system. Then, the controllers required to manage communication between the transceiver, which acts as data source, and the PC, which is the receiver, are implemented on the FPGA embedded in the SmartFusion2 SoC.

For the successful realization of this project it was necessary to carry out both hardware and software development tasks. In addition, the programming languages C and VHDL were used, as well as the communication standard protocols Serial Peripheral Interface (SPI) and Low Voltage Differential Signaling (LVDS).

The aim of this project, was to design a functional prototype for the transformation of energy based on the principle of piezoelectricity, in order to harvest the energy produced. After some research, this is determined to be the best postulate to generate electrical power at a low scale for applications in electrical systems that require low voltage power supply, working as a stand-alone power to charge both, medical and electronic devices.

When a piezoelectric material is exposed to mechanical deformation, a voltage is produced. The theoretical behaviour can be appreciated in the following image:

Therefore, the energy that can be harvested depends on two factors: the properties of the piezoelectric material and the amount of deformation applied to the material.

Some of the materials that show piezoelectricity are: quartz, lead zirconate titanate (PZT), aluminum nitride (AlN), zinc oxide (ZnO) and polyvinylidene fluoride (PVDF).

The special property of these piezoelectrics is that it allows them to convert physical energy into electricity, AC. However, we need DC, not AC to power devices. This problem can be solved creating a rectifier bridge with diodes to convert the power from AC to DC, and thus be able to use it.

Although piezoelectric elements generate a lot of voltage, they do not generate many amps. We can solve this problem by wiring all the piezoelectric elements in parallel

Taking into account all the mentioned above, the prototype that has been created is formed by 7 PZT piezoelectrics of 35 mm diameter, as shown in the picture at the top pf the page.

Finally, it has been proved, when charging some capacitors, that it is better to have the shoe sole outside, placed on a smooth surface (as a carpet) and then making pressure on them. In such a way, the most relevant results were obtained. The capacitors were charged more quickly than while walking with the shoe sole inside. The order of magnitude of the power generated by this assembly was mW, and the energy generated was in the order of mJ.

In the last years, the Vehicular Ad hoc Networks or VANET’s are gaining relevance in order to improve traffic management and road safety. In addition, autonomous cars technology has been a boost for VANET’s research in recent years. One of the main services provided by a VANET is the localization support from dodge dealership with a  Global Position System or GPS. However, the GPS has an error of 3 to 7 meters, a better accuracy may be necessary in some applications. Moreover, in areas with no GPS coverage like tunnels there would not be any localization support. Therefore, another localization method should be implemented to improve accuracy and coverage, which is the main purpose of this project.

In this degree project, a VANET has been used to provide vehicle localization. However, conventional VANETs devices are very expensive and have very large power consumption, so we use a Wireless Sensor Network or WSN as a low-cost and low-power alternative. WSN’s are similar to wireless ad hoc networks, but they have a lower cost. However, these resource-constraint networks does not allow implementing complex algorithms.

The localization algorithm selected in this project is the Fuzzy Ring-Overlapping Range-Free or FRORF. It has been modified so it could be implemented in resource-constraint nodes with low computational capabilities. This algorithm has been implemented in wireless nodes developed by the B105  Electronic Systems Lab and several tests have been performed in different scenarios. The position of the vehicle has been obtained in these scenarios and has been compared with the position obtained from a commercial GPS module.

With the results it is possible to conclude that the implemented algorithm has an error of 1 to 9 meters. This error is similar to the GPS error, so the FRORF algorithm can provide a reasonable position of a car. Althougth the accuracy needed for a VANETs is not solved, the algorithm provides localization in interior areas. This advance is very important as localization support services may be provided in zones without GPS coverage.