A low power architecture for AER event-processing microcontroller

This paper presents a custom MSP430™-compatible microcontroller, specifically tailored for quasi-digital processing Address Event Representation (AER) events. Main target applications are fully reprogrammable sensory systems where events pre-processing has to be carried out by means of easily-tunable elaboration algorithms; a microcontroller-based design could provide the right trade-off between flexibility and performance. Key features are good time resolution, high reactivity, on-demand only processing and power consumption reduction. The proposed architecture has been analyzed and compared with an open source MSP430TM-compliant microcontroller (openMSP430) in terms of performance and power consumption. Accurate and wide cases-spectrum simulations (targeting ASIC technology) show an average power consumption reduction ranging from 50 % (same operating frequency) up to 79 % (same maximum event rate); equivalently, with the same power budget, an average improvement of either resolution of 84 % or maximum event rate of 1020 % is obtained

Raspberry Pi based Modular System for Multichannel Event-Driven Functional Electrical Stimulation Control

This paper describes the implementation and testing of a modular software for multichannel control of Functional Electrical Stimulation (FES). Moving towards an embedded scenario, the core of the system is a Raspberry Pi, whose different models (with different computing powers) best suit two different system use-cases: user-supervised and stand-alone. Given the need for real-time and reliable FES applications, software processing timings were analyzed for multiple configurations, along with hardware resources utilization. Among the results, the simultaneous use of eight channels has been functionally achieved (0% lost packets) while minimizing system timing failures (excessive processing latency). Further investigations included stressing the system using more constraining acquisition parameters, eventually limiting the usable channels (only for the stand-alone use-case)

High-Level Synthesis of a Single/Multi-Band Optical and SAR Image Compression and Encryption Hardware Accelerator

Transmitting images from earth observation satellites to ground is a major challenge, and a compression/encryption stage is actually mandatory. Development of hardware accelerators is highly recommended, both to relieve the software from such demanding task, and to improve performance, aiming at quasi-real-time data processing. To this end, we discuss the design, development, deployment and test of a FPGA-based accelerator, featuring a lossless and lossy (near-lossless) compression, including the data encryption too. Its architecture is well suited for different image types, including single- and multi-band optical and SAR images and can be fully run-time configurable. Measured performance showed a throughput of 10 Msamples/s, in agreement with related state-of-the-art works, focused on lossless compression only

LOW LATENCY ON-BOARD DATA HANDLING FOR EARTH OBSERVATION SATELLITES USING OFF-THE-SHELF COMPONENTS

Satellite Earth Observation (EO) is nowadays receiving significant attention. In this regard, the latency of EO product provision to the ground segment is undoubtedly among the first key performance indicators for these systems. The European Union Horizon 2020 EO-ALERT project aims at overcoming the limitations of traditional Near Real-Time (NRT) onboard data chain architectures by moving all the critical processing tasks on the flight segment and accelerating them using high-performance commercial off-the-shelf (COTS) devices. The resulting architecture minimizes the amount of transmitted data and eliminates ground-based data processing from the EO data chain, hence achieving actual real-time product delivery in less than 5 min with optical and Synthetic Aperture Radar (SAR) data. This paper presents the performance benefits of a mixed software-hardware design of the CPU Scheduling, Compression, Encryption, and Data Handling (CS-CEDH) Subsystem responsible for data compression and encryption as well as data routing and scheduling tasks. Compared to a software-only solution, the exploited High-Level Synthesis (HLS) methodology enables 5 to 7-fold speed-up in onboard image compression and encryption tasks and 2 to 5-fold reduction in the contribution of the CS-CEDH Subsystem to the overall onboard image data chain while contributing by less than 1 s to the delivery of the alerts to the end-user

A new dynamic tactile display for reconfigurable braille: implementation and tests

Different tactile interfaces have been proposed to represent either text (braille) or, in a few cases, tactile large-area screens as replacements for visual displays. None of the implementations so far can be customized to match users' preferences, perceptual differences and skills. Optimal choices in these respects are still debated; we approach a solution by designing a flexible device allowing the user to choose key parameters of tactile transduction. We present here a new dynamic tactile display, a 8 × 8 matrix of plastic pins based on well-established and reliable piezoelectric technology to offer high resolution (pin gap 0.7mm) as well as tunable strength of the pins displacement, and refresh rate up to 50s(−1). It can reproduce arbitrary patterns, allowing it to serve the dual purpose of providing, depending on contingent user needs, tactile rendering of non-character information, and reconfigurable braille rendering. Given the relevance of the latter functionality for the expected average user, we considered testing braille encoding by volunteers a benchmark of primary importance. Tests were performed to assess the acceptance and usability with minimal training, and to check whether the offered flexibility was indeed perceived by the subject as an added value compared to conventional braille devices. Different mappings between braille dots and actual tactile pins were implemented to match user needs. Performances of eight experienced braille readers were defined as the fraction of correct identifications of rendered content. Different information contents were tested (median performance on random strings, words, sentences identification was about 75%, 85%, 98%, respectively, with a significant increase, p < 0.01), obtaining statistically significant improvements in performance during the tests (p < 0.05). Experimental results, together with qualitative ratings provided by the subjects, show a good acceptance and the effectiveness of the proposed solution

Ultra-Miniaturised CMOS Current Driver for Wireless Biphasic Intracortical Microstimulation

This work shows an ultra-miniaturised and ultralow-power CMOS current driver for biphasic intracortical microstimulation. The CMOS driver is composed of a leakage-based voltage-to-current converter and an H-bridge circuit providing biphasic charge-balanced current stimulation. The circuit has been simulated, fabricated and tested. The current driver consumes 1.87 µW with a supply voltage of 1.8 V, and it occupies a silicon area of 15×12.4 µm 2 . The driver works in linearity in the current range between 23−92 µ

Live Demonstration: A Real-Time Bio-Mimetic System for Multichannel FES Control

This demonstration presents a bio-mimetic system for the real-time multichannel control of Functional Electrical Stimulation (FES). The intensities of the FES profiles are directly mapped by processing surface ElectroMyoGraphic (sEMG) signals detected from synergistic muscles, thus achieving a user-comfortable stimulation that follows the monitored physiological patterns. Furthermore, a user-dedicated calibration routine and multiple versatile operating configurations allow the system to be integrated into standard rehabilitation protocols to enhance the restoration of motor functionalities

A Biomimetic Multichannel Synergistic Calibration for Event-Driven Functional Electrical Stimulation

In this paper, we present the Profile Extraction (PE) algorithm, which allows the computation of a multi-channel profile highly correlated with voluntary muscle activity. This event-based profile can be used as biomimetic control during the calibration phase of a Functional Electrical Stimulation (FES) system. The adoption of the PE technique represents the preliminary step to extend the applicability of our event-driven paradigm to control the coordinated multi-joint movements. Through an experimental campaign, we tested the improvements made by the use of PE in the FES calibration, assessing the reproducibility between the voluntary and stimulated movements. Results show a 2 % increase of the median correlation value for a single-channel exercise and a 3.6 % increase for a dual-channel one. A statistical decrease of normalized Root Mean Square Error has been obtained for the dual-channel exercise (p < 0.05)