Tutorial: A Versatile Bio-Inspired System for Processing and Transmission of Muscular Information

Device wearability and operating time are trending topics in recent state-of-art works on surface ElectroMyoGraphic (sEMG) muscle monitoring. No optimal trade-off, able to concurrently address several problems of the acquisition system like robustness, miniaturization, versatility, and power efficiency, has yet been found. In this tutorial we present a solution to most of these issues, embedding in a single device both an sEMG acquisition channel, with our custom event-driven hardware feature extraction technique (named Average Threshold Crossing), and a digital part, which includes a microcontroller unit, for (optionally) sEMG sampling and processing, and a Bluetooth communication, for wireless data transmission. The knowledge acquired by the research group brought to an accurate selection of each single component, resulting in a very efficient prototype, with a comfortable final size (57.8mm x 25.2mm x 22.1mm) and a consistent signal-to-noise ratio of the acquired sEMG (higher than 15 dB). Furthermore, a precise design of the firmware has been performed, handling both signal acquisition and Bluetooth transmission concurrently, thanks to a FreeRTOS custom implementation. In particular, the system adapts to both sEMG and ATC transmission, with an application throughput up to 2 kB s-1 and an average operating time of 80 h (for high resolution sEMG sampling), relaxable to 8Bs-1 throughput and about 230 h operating time (considering a 110mAh battery), in case of ATC acquisition only. Here we share our experience over the years in designing wearable systems for the sEMG detection, specifying in detail how our event-driven approach could benefit the device development phases. Some previous basic knowledge about biosignal acquisition, electronic circuits and programming would certainly ease the repeatability of this tutorial

A wearable mechatronic device for extracorporeal blood ultrafiltration

The interest in the design of portable and wearable medical devices is related to both the relevant clinical and social benefits for patients and the potential economic savings for national health services. Biomedical technologies are improving at a very fast rate and represent an extraordinary means to develop innovative portable and wearable devices which can help people live in a prosperous way, in particular reducing sorrow in case of disease. This leads to a widespread effort to develop devices which can execute at home therapies that are usually performed in hospitals. This thesis presents a new wearable and portable device for extracorporeal blood ultrafiltration, named WUF (Wearable UltraFiltration device), able to remove excess fluids from fluid overload patients with chronic kidney disease and/or congestive heart failure. The design requirements that a modern wearable device for extracorporeal ultrafiltration must meet have been identified thanks to a thorough literature review on previous similar proposals followed by an extensive risk analysis. The design of the WUF prototype has faced several difficulties, ranging from the identification or conceivement of safe and reliable components to the design of a compact and neat layout. For most components it was possible to identify commercial (off-the-shelf) products meeting the requirements, nonetheless for some others, specific investigations, studies and developments were needed and led to the design of customized solutions or the formulation of original approaches. The design of an effective, efficient, safe and reliable control architecture, based on two microcontrollers and one microcomputer, the implementation of the control logic and of a graphical user interface have been carried out too being essential features of such a mechatronic device. A backpack/trolley design has been chosen as the layout for the device, since such a solution guarantees the best tradeoff between miniaturization and ergonomics. The design introduces an original positioning of the vast majority of components in three independent planar panels: one for disposable components, one for non-disposable devices and one for electronic boards and controllers. This arrangement of components can drastically simplify and speed up the in-hospital operations needed before and after a therapy with the WUF

Enabling intuitive and efficient physical computing

Making tools for technology accessible to everyone is important for diverse and inclusive innovation. Significant effort has already been made to make software innovation more accessible, and this effort has created a movement of citizen developers. These citizen developers have the drive to create, but not necessarily the technical skill to innovate with technology. Software, however, has limited impact in the real world compared to hardware and here, physical computing is democratising access to technological innovation. Using microcontroller programming and networking, citizens can now build interactive devices and systems that respond to the real world. But building a physical computing device is riddled with complexity. Memory efficient but hard to use low-level programming languages are used to program microcontrollers, implementation efficient but hard to use wired protocols are used to compose microcontrollers and peripherals, and energy efficient but hard to configure wireless protocols are used to network devices to each other and to the Internet. This consistent trade off between efficiency and ease of use means that physical computing is inaccessible to some. This thesis seeks to democratise microcontroller programming and networking in order to make physical computing accessible to all. It provides a deep exploration of three areas fundamental to physical computing: programming, hardware composition, and wireless networking, drawing parallels with consumer technologies throughout. Based upon these parallels, it presents requirements for each area that may lead to a more intuitive physical computing experience. It uses these requirements to compare existing work in the space and concludes that no existing technology correctly strikes the balance between efficient operation for microcontrollers and intuitive experiences for citizen developers. It therefore goes onto describe and evaluate three new technologies designed to make physical computing accessible to everyone

Graceful performance modulation for power-neutral transient computing systems

Transient computing systems do not have energy storage, and operate directly from energy harvesting. These systems are often faced with the inherent challenge of low-current or transient power supply. In this paper, we propose “power-neutral” operation, a new paradigm for such systems, whereby the instantaneous power consumption of the system must match the instantaneous harvested power. Power neutrality is achieved using a control algorithm for dynamic frequency scaling (DFS), modulating system performance gracefully in response to the incoming power. Detailed system model is used to determine design parameters for selecting the system voltage thresholds where the operating frequency will be raised or lowered, or the system will be hibernated. The proposed control algorithm for power-neutral operation is experimentally validated using a microcontroller incorporating voltage threshold-based interrupts for frequency scaling. The microcontroller is powered directly from real energy harvesters; results demonstrate that a power-neutral system sustains operation for 4–88% longer with up to 21% speedup in application execution