Ahnsei's Portfolio - Neural Interface Electronics

Neural Interface Electronics

This page shows neural interface electronics that I developed from scratch since 2007.

Edge AI-Based Closed-Loop Neural Interface System for Gait Rehabilitation

after Spinal Cord Injury (2021-2023) @TAMU

Keywords: Edge-AI, Edge Impulse, Dual-Core MCU, STM32H7, STM32L4, Gait Rehabilitation, Closed-Loop E-Stim

Conceptual study design & Implemented Edge-AI-Based Closed Stimulation System

Ceaseless human intervention is necessary to set thresholds triggering stimulation pulse generation for each subject manually to achieve a maximal electrical stimulation (E-Stim) effect improving weaken motor outputs. To address this in the name of minimizing human intervention and eliciting the maximum effect of E-Stim, I developed an edge-AI-based closed-loop neural interface system. Unlike ordinary AI systems, this system does not require huge power consumption and an internet connection. All functions including neural amplifiers, neural stimulators, and digital (MCU) circuits were integrated into a single printed circuit board. I used one STMicroelectronics' 32-bit dual-core microcontroller (MCU) (STM32H755BIT3) as the main MCU and one Arm Cortex-M4 32-bit MCU (STM32L476RGT6TR) as the sub-MCU to generate stimulation pulses. AI model, automatically classifying threshold level without human intervention, was developed using Edge Impulse and deployed on the main MCU. Whole functions in the system were successfully validated through the benchtop tests and animal experiments with a spinal cord injured rat. Also, the developed Edge-AI based closed-loop system can be used as a reference design when developing more compact and portable/implantable neural interface systems in the near future.

Related achievements:

A conference paper has been accepted and selected for a podium talk at the 11th International IEEE EMBS Conference on Neural Engineering (NER2023) https://2023.ieee-ner.org/.

Fully-Implantable Plantar Cutaneous Augmentation System for Rats using Closed-loop Electrical Nerve Stimulationneural interface system Cord Injury (2018-2021) @TAMU

Keywords: Fully-implantable neural interface system, wireless (Bluetooth) data transmission, wireless power transmission, closed-loop E-Stim, plantar cutaneous feedback, sensory augmentation

Related achievements:

A. Shon, K. Brakel, M. Hook and H. Park, "Fully Implantable Plantar Cutaneous Augmentation System for Rats Using Closed-loop Electrical Nerve Stimulation," in IEEE Transactions on Biomedical Circuits and Systems, vol. 15, no. 2, pp. 326-338, April 2021, doi: 10.1109/TBCAS.2021.3072894. (LINK)
Featured Article (LINK)

A. Shon, K. Brakel, M. Hook and H. Park, "Fully Implantable Plantar Cutaneous Augmentation System for Rats Using Closed-loop Electrical Nerve Stimulation," in IEEE Transactions on Biomedical Circuits and Systems, vol. 15, no. 2, pp. 326-338, April 2021, doi: 10.1109/TBCAS.2021.3072894. (LINK)
1st Place, Doctoral Lightning Talk, Texas A&M University System (Mar.2022) (LINK)

Neural Signal Acquisition System for Peripheral Nerve Activity Using

a Multichannel Cuff Electrode (2017-2018) @KIMM

Keywords: Multichannel Neural Recording, Sciatic Nerve

Related achievement:

A. Shon, and J-U. Chu, (Nov. 10-11, 2017), “Neural signal acquisition system for peripheral nerve activity using a multichannel cuff electrode”, 2017 The Korean Society of Medical & Biological Engineering Conference. Jeonbuk, South Korea.

Implementation of Patented Glove-type wireless ECG Monitoring Device for Paramedics (2014-2015) @KUMC

Keywords: Dry-electrode driving circuit, ECG, Bluetooth, MCU

Fully-Implantable Wireless Neural Interface System (2011-2014) @KIST

Keywords: Medical Implant Communication Service (MICS), ENG Recording, Peripheral Nerve Stimulation, Zarlink Semiconductor, Microcontroller (MSP430), Transcutaneous Power Transmission

A Wireless Implantable Neural Interface System for Concurrent Peripheral Nerve Stimulation and Recording (2011-2013) @ KIST

Keywords: Fully-implantable device, neural recording, neural stimulation

Related achievement:

A. Shon, J-U. Chu, and I. Yoin, (Jul. 11-15, 2017), "A Wireless Implantable Neural Interface System for Concurrent Peripheral Nerve Stimulation and Recording" 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Jeju Island, South Korea.

Dry-Electrode Wireless EMG Module (2011-2012) @KIST

Keywords: Dry-electrode driving circuit, ECG, Bluetooth, MCU

Bottom View

Top View

Raw & Rectified EMG Signals

Multi-Channel High-Resolution Portable Digital EEG System (2010-2011) @Yonsei University

Keywords: EEG Recording, Real-time monitoring, ADS1298, Portable, Multi-Channel, High-Resolution, ATmega128, LabVIEW GUI

Top and bottom view of multi-channel high-resolution portable digital EEG system

Related achievements:

MS Thesis (Link)

Patient Monitoring (4-CH EEG) Module for Operating Rooms (2009-2010)

@Yonsei University

Keywords: EEG Recording, Patient Monitoring, Patient Protection Circuit, ATmega128

Multi-Channel High-Resolution Portable Digital EEG System (2010-2011) @Yonsei University

Keywords: EEG Recording, Real-time monitoring, ADS1298, Portable, Multi-Channel, High-Resolution, ATmega128, LabVIEW GUI

Pre-Amplifier

Main-Amplifier + Digital Control Unit (MCU: ATmega-128)

Wireless Pulse Oximetry (SpO2) Measurement System

using a Zigbee Network (2007-2008) @ KoreaTech

Keywords: Wireless Pulse Oximetry, Zigbee Network, ATmega128, LabVIEW GUI

I developed a wireless pulse oximetry measurement system using a Zigbee network for my capstone design as a graduation requirement. I designed, developed, and evaluated the entire system from scratch, including the optical sensor, current-to-voltage converting circuit, analog filters, MCU programming, and GUI software. The developed GUI displayed wirelessly transmitted data to monitor a user's blood oxygen saturation level. I won the 3rd prize for the best graduation work in my department. Then, my work was displayed at COEX, one of the largest exhibition halls in South Korea. Since then, I have been designing, developing, and evaluating various wearable/implantable neural interface systems.

Hardware