TFM: Design of a Communication System Through the Body
Posted on by rookie

The loss of a limb is a traumatic event for a human being, permanently altering the way they perform everyday tasks. Currently, most of these patients require a prosthesis for both aesthetic and functional reasons. Today, there are various types of prostheses, with robotic arms being the most commonly used for movement. These mechanical and/or electrical devices mimic human movements, controlled by the person. At present, the communication between the robotic arm and the user is established either through implants inside the body or via vulnerable communication methods.

The objective of this master’s thesis is to design a non-invasive communication system that uses the human body as a transmission medium. This approach is based on the innovative Human Body Communication (HBC) technology, which is part of Wireless Body Area Networks (WBAN). It is designed for wearable devices on the surface or inside the human body, specifically in the field of medicine. The goal is to transmit electrical or electromagnetic signals using the conductive properties of the human body.

To achieve this, an exhaustive study was conducted to understand how the human body behaves when a signal is transmitted at the selected frequency of 2.45 GHz. The signal will be transmitted through the patient’s forearm, which consists of multiple layers of materials with different dielectric properties. Therefore, computational simulations are necessary to analyze how the signal behaves.

This project is based on two experimental studies aimed at measuring propagation losses. The goal is to place the transmission and reception devices on the skin’s surface, using study [1] as a reference to calculate the signal losses through the multiple layers of the spleen. Additionally, the signal losses associated with transmission through the interior of the forearm, between the transmitter and receiver, were evaluated based on the data from study [2].

Once the system requirements were established, preliminary tests were conducted to validate the designed system. The results showed greater propagation losses than the theoretical estimates, prompting the project to focus on developing a functional prototype that is small, low-cost, and energy-efficient. The following image shows the completed system.

Finally, after testing the assembled system, it was determined that the selected insulator, RFSW-S-125-FR-PSA from Laird Technologies, is effective for communication through the air. However, aluminum yielded better results for communication through the body. On the other hand, the selected antenna was not ideal due to market limitations.

The results obtained suggest multiple areas for improvement and encourage further research to optimize the system.

References:

[1] Y. M. G. M. D. Zhi Ying Chen, «Propagation characteristics of electromagnetic wave on multiple tissue interfaces in wireless deep implant communication,» IET Microwaves, Antennas & Propagation, vol. 12, nº 13, pp. 2034-2040, 2018.

[2] C. G.-P. A. F.-L. A. V.-L. G. V. J. S. M. I. I. B. S. M. I. a. N. C. S. M. I. Ra´ul Ch´avez-Santiago, «Experimental Path Loss Models for In-Body Communications Within 2.36–2.5 GHz,» IEEE JOURNAL OF BIOMEDICAL AND HEALTH INFORMATICS, vol. 19, nº 3, pp. 930-937, 2015.

TFM: Design and implementation of a simulation environment for transcranial magnetic stimulation in human and mouse brains.
Posted on by rookie

The study of the human brain is currently a fundamental area of interest in science due to the complexity and diversity of functions performed by this organ. Although the brains of humans and mice differ in size and structure, they share numerous fundamental principles that allow scientists to extrapolate findings from rodent studies to humans. However, neuroscience research faces significant challenges due to the intrinsic complexity of nervous systems and the ethical and practical limitations associated with direct experiments on living organisms.

In this context, simulation environments have emerged as powerful tools for research. These environments allow for the modelling and detailed analysis of neural processes in a controlled setting without involving any living organisms. The ability to simulate brain activity when stimulated by external factors not only facilitates understanding of the brain’s response to these stimuli but also can accelerate the development of treatments for neurological diseases, such as cancer or stroke.

The main objective of this work is to develop a simulator capable of stimulating human and mouse brains using the transcranial magnetic stimulation method and quantifying the impact of various parameters in the simulation.

To achieve this objective, various brain simulators currently in use have been analysed, and one has been selected as the basis for the simulator. Additionally, the functioning of transcranial magnetic stimulation and the necessary instruments for carrying out this stimulation method have been studied. Furthermore, the modelling of the magnetic field generated by coils, both with and without a core, has been explored.

After gathering all this information, the simulator was completed, capable of simulating both human and mouse brains. Moreover, it allows for generating stimuli in the target brain with fully customized coils, as it is possible to model them by varying parameters such as height, radius, or number of turns. The intensity circulating through these coils can also be adjusted. Additionally, various commercial coils and stimulation systems consisting of multiple coils were successfully modelled.

Finally, various tests were conducted to verify that the modelling of the different coils was accurate and to measure different parameters. The parameters measured included the maximum radial electric field generated in the brain for each coil, the value of this electric field at different depths, the effect of the distance between the skull and the coil on the stimulation, and the field generated by the stimulation systems. Subsequently, all these tests were parametrized.

This project has developed and implemented a simulator capable of replicating brain stimulation in humans and mice through transcranial magnetic stimulation. The simulator allows customization of parameters such as coil position and number, distance from the skull, or stimulation intensity. After various tests, its accuracy has been confirmed, helping to reduce risks and improve personalized TMS treatments. Additionally, the inclusion of mouse models reduces the need for live experiments. The simulator offers applications in neuroscience research, therapy optimization, and the development of new clinical protocols.

Therefore, it can be confirmed that the proposed general objectives have been achieved and the technical feasibility of the project has been demonstrated.

All the code corresponding to the simulator is located in the following repository: https://github.com/rfparra/TFM

TFG: Development of algorithms for monitoring physiological parameters to assist drivers
Posted on by b105

One of the main problems that we face today is traffic accidents. In recent years there have been more than 1000 deaths per year in Spain due to this reason, however, it is extremely difficult to find products on the market that assist the drivers from all of Orlando to deal with this problem.

In order to provide a solution to the problem outlined, at the B105 Electronic Systems Lab, a bracelet wearable was designed, which monitors the driver’s body temperature, stress level, heart rate, blood pressure, and the level of alcohol in the air.  This device is intended to provide a tool for the drivers to assist them to check if they are physically good and mentally ready to drive. However, the reliability expected in this device was not achieved, to use it as an end system in a user, due to a lack of time. For this reason, the main objective of this TFG has been to achieve the greatest performance of the electronic device designed in the previous project.

The first step has been to carry out a study of other similar products that can be found in the market, as well as the design of the device.

Then, an analysis of the parameters obtained with the bracelet has been conducted, to understand what aspects need to be known about them to measure them, and the different methods that exist to obtain them. In addition, the measurement method used by the device for each of them has been analysed in further detail, focusing on what problems it could present, and which factors could affect them.

Afterwards, tests have been carried out in all the modules in a separate way, in which the previous analysis has been considered. Different measurements have been performed on all the sensors during the tests, to calibrate them and to check their behaviour towards the factors that affect them.Through these tests, it has been concluded which is the optimal method to obtain each one of the parameters, the design problems that the device presents, and how it could be improved.

Lastly, the integration of all the modules has been carried out, in which besides obtaining all the parameters considering the conclusions obtained from the tests, an alarm system has been carried out. This system warns the user by the vibration of the bracelet, if a value out of a healthy range is detected in any of the measurements on the parameters. This integration has also been tested and depurated using the debugger.

Finally, it can be concluded that the main objective of the project has been achieved, although some changes would be necessary to improve its functionality, in order to be used as an end device.

TFG:DESIGN AND DEVELOPMENT OF AN LOW-COST WIRELESS PROSTHETICS ARM
Posted on by b105

This final project focuses on the field of robotics aimed at developing automated prostheses, helping to recover part of the lost mobility of people who need it. More specifically, it will focus on analysing and designing a wirelessly controlled robotic arm, which will serve as the basis for future projects at the B105 Electronic Systems Lab.

To this end, a preliminary study was carried out of the technologies currently used to develop a robotic arm, extracting which components can be used to carry out the movement and control of the arm, what considerations must be taken into account to design the different parts that make it up and what prototypes currently exist, extracting their characteristics to try to find a way to improve them.

Once the previous study had been done, the design of the arm was carried out, where the way to control it, the type of wireless communication, the motorization to be used and how it is fed were chosen. After this, we have chosen the components that best suit to meet the specifications requested, the modeling program has been used to design the parts, the materials used to build them, and the type of manufacture used to make them. It has been concluded that the parts must be manufactured by 3D printing, that Bluetooth will be used as technology for wireless communication, and servomotors to motorize the system.

Afterwards, the connection has been made, the design of the pieces by means of a 3D modeling program and the subsequent manufacture of part of them by means of 3D printing. A mobile application has also been developed to control several servomotors and check the wireless connection between the arm and the mobile, in addition to having created several integration files on the board to check the operation of the components.

Then different tests have been carried out, using the software created, where different components have been connected, and it has been checked whether they work correctly or not.

In the end a complete functionality has not been achieved, but a partial functionality has been achieved where it has been possible to connect by means of Bluetooth the mobile and the arm, to move two servomotors, with which two fingers have been moved, and the battery has been controlled by means of a series of leds. Several problems have also been found with regard to the power supply of the servomotors and the reception of data sent by the board that controls the servomotors to the mobile.

TFM: Development of an electronic system for monitoring people’s parameters
Posted on by b105

Road safety is one of the objectives of the European Union due to the high number of infractions committed every year by drivers and pedestrians, and the large amount of accidents with fatalities registered in Europe year by year. Therefore, any step taken in order to deal with this problem is beneficial for everyone.

Current technology allows increasing the security measures of vehicles, which, together with consciousness-raising of drivers and pedestrians, take us one step closer to the reduction of these figures. Every day more people decide to use biosensors for controlling their vital signs. The transfer and adaptation of the aforementioned systems to the situation in which a driver is, permit to complement both legal actions accomplished and consciousness-raising measures, improving road safety.

The main objective of this Master’s thesis consists of the development of an electronic system that allows drivers to notice the indisposition to drive, permitting to avoid an accident and also an infraction.

After analyzing the parameters that affect driving and are related to the driver, those that can be monitored in a non-intrusive way and without using disposable material were chosen: body temperature, blood pressure, pulse, stress level, and alcohol level.

All of that has been gathered in a single module formed by three PCBs. Both hardware and software have been designed. The proposal has been assembled and the case and the band have been 3D-printed in order to form the final device with a smart bracelet form factor. This module has been designed with the purpose of having small dimensions and low consumption since it is powered by a battery.

Finally, several tests have been carried out to verify the proper functioning of the system. The biggest challenge was found while obtaining blood pressure based on the photoplethysmography signal. Through those tests, the developed software could be adapted according to the results obtained, since offset values that have to be applied and the times that sensors need could be known. This also permitted to discover errors committed during previous stages of the development process.

Therefore, it can be confirmed that the general objectives set have been accomplished.

Technical viability of the proposal could be proved, and this informs of the existence of several application fields that the project could have, as is the case of professional drivers.