Embedded Systems & Hardware Engineer
Sean Conway
Howdy! I'm an embedded systems and hardware engineer with a passion for building things that move, sense, and communicate. I enjoy taking ideas from concept to prototype to production, and I love learning new technologies along the way.
Texas A&M University B.S. Electronic Systems Engineering Technology Minor in Cybersecurity
Projects
RefRemote V1
Wearable Grappling Officiating System | Production Redesign
RefRemote is a wearable BLE remote with haptic feedback for grappling competition officiating. This version moves the project toward a production-grade system: a ground-up redesign of the platform, firmware, and hardware.
Platform & Firmware
- Switched microcontroller platform to the nRF52840 (Raytac MDBT50Q-P1MV2 module), the industry-standard platform for BLE wearables, for improved wireless performance and power consumption
- Switched to Zephyr RTOS-based firmware via the nRF Connect SDK for lighter weight, more granular control, and production-grade reliability
- Formal, versioned wire protocols for both links: a USB protocol between the dongle and the browser-based scoreboard, and a BLE radio protocol between the dongle and the remotes
- Flashing interface swapped to SWD via a Tag-Connect header, eliminating the boot/reset button sequence and UART header the previous version needed
Both protocols are backed by host-level automated test suites, all passing, so protocol changes are caught before they ever reach hardware.
Wireless Bridge
- nRF52-based USB-C dongle (Raytac MDBT50Q-CX-40) isolates the wireless link from the host PC's own radio variability
- Built and flashed on real hardware, with a confirmed encrypted BLE connection carrying live telemetry
- No pairing procedure; encryption keys are provisioned at build time so the link is encrypted from the first connection
- Tuned connection parameters hold a 120 ms end-to-end acknowledgement budget, with 25 ms allocated to the radio hop itself
Remote Hardware
Status: schematic complete, components selected, and the PCB designed. It's currently undergoing pre-fabrication revision to verify functionality, manufacturability, and EMC before ordering.
- Switched to a 4-layer PCB for improved trace routing and reduced EMI/EMC risk, especially with the introduction of switching regulators
- Introduced an nPM1300 Power Management IC, purpose-built to pair with nRF52-series microcontrollers on battery-powered BLE wearables, consolidating regulator, charger, and fuel gauge functionality into a single component
- TPS63002 buck-boost regulator supports a stable LED array and consistent haptic strength across the battery's voltage range
- Dual haptics: both LRA and ERM haptic actuators deliver high-amplitude clock expiration notifications and low-amplitude input acknowledgements, so user input transmissions never fail silently, clock expirations are always unmistakable, and battery life lasts a full day of officiating use
- 7 GPIO buttons supporting a fuller ruleset across multiple grappling disciplines
- 4 RGB LED indicator array supporting richer indication functionality
Scoreboard
A live web app scoreboard (wrsl.app) eliminates the need to download a scoreboard application locally, so it can be run free on any Chromium browser.
RefRemote V0
Wearable Grappling Officiating System | PCB and Enclosure Prototypes
RefRemote is a wearable BLE remote with haptic feedback for grappling competition officiating. This version spans several development iterations of a custom two-layer PCB and enclosure for an ESP32-based implementation of the system.
Hardware
- ESP32-C3-MINI-1 microcontroller module
- LIS3DH IMU, DRV2605L haptic driver, and MAX17048 fuel gauge over I2C
- MCP73831 battery charger IC and XC6220 LDO regulator
- USB-C charging port and power switch
- 5 GPIO buttons, plus dedicated BOOT and RESET buttons
- UART flashing header pins
- 4 single-color LED indicators
Component selection and PCB layout balanced application functionality, unit cost, availability and lifecycle, target form factor, manufacturability, testability, and EMI performance. Firmware for this iteration was written in C++ using the Arduino IDE.
Bring-Up & Iteration
The initial build validated general functionality, but the ESP32 first failed to enter bootloader mode. The cause turned out to be the BOOT button wired to the wrong pin, from a mix-up in module version documentation. I recovered by soldering a fine-gauge wire to the correct pad underneath the module and holding it to GND during reset, which let me validate the rest of the board before ordering a revision. Apart from the boot-pin issue, every other subsystem validated successfully, including the haptic driver, IMU, and fuel gauge interfaces, recharge circuitry, buttons, and LEDs.
The next iteration corrected the boot-pin error and reworked the layout for a slimmer enclosure, moving to a double-sided component layout and lower-profile buttons. This phase also included trialing several haptic actuators, both ERM (Eccentric Rotating Mass) and LRA (Linear Resonant Actuator) motors, to find one that delivered strong haptics without compromising battery life, along with early experiments with an nRF52-based BLE dongle to improve radio link reliability independent of whatever PC is running the scoreboard.
RefRemote Proof-of-Concept
Wearable Grappling Officiating System | Perfboard Prototype
RefRemote is a wearable control system that allows referees in amateur wrestling and jiu-jitsu competitions to operate the match clock and scoring system directly from their wrist. Today, tournaments require 2–3 table workers per mat to run the clock, record scoring, and signal time expiration. These volunteers are often inexperienced or unreliable, leading to scoring mistakes, missed time signals, and delays that negatively impact competitors and officials. RefRemote replaces table staff by enabling referees to control match timing and scoring through a wrist-mounted interface with tactile inputs, gesture-based clock control, and haptic feedback notifications.
I had the opportunity to build the initial iteration of the RefRemote prototype as a project in my Embedded Sensors and IoT Systems course at Texas A&M.
Hardware
- ESP32-C3-Supermini dev board
- 3 tactile push buttons, 1 RGB LED, 1 white LED
- Haptic vibration motor
- MAX17043 fuel gauge module
- LIS3DH IMU module
- 3.7V LiPo battery
The ESP32 interfaces with the fuel gauge and IMU over I2C and runs firmware built with C++ in the Arduino IDE. The IMU drives a machine learning motion classifier, based on logistic regression, that distinguishes between the device at rest, idle movement, and a distinct flicking gesture used to start the clock without touching the buttons. The pair of remotes interfaced with a Raspberry Pi over BLE, which ran a browser-based graphical scoreboard, and communicated with a second Raspberry Pi over MQTT to queue up matches from the bracket and upload results. See the report and repo for more details.
Capstone
mmWave Radar 3D Imaging System
This capstone project is a proof-of-concept security screening platform that fuses four independent sensing modalities: millimeter-wave synthetic aperture radar, infrared imaging, visible-light facial recognition, and Bluetooth-integrated metal detection, into a single operator dashboard for concealed weapon detection. Built as an iteration on a prior capstone team's gantry and radar hardware, the project's core challenge was improving the mmWave radar imaging resolution and speed while making disparate subsystems (a Raspberry Pi, a Windows radar workstation, and a BLE-connected ESP32-based metal detector wand) work together as one coherent, real-time system.
In my role as Systems Integration Engineer, I was responsible for architecting how the independent subsystems communicated and combined into a unified product. Troubleshooting the system bring-up was a major challenge, as the hardware and software were handed off from the previous team and had to be reverse-engineered and reimplemented before they could be utilized, iterated upon, and integrated with novel functionality. I contributed significantly to every aspect of the system's functionality.
My Contributions
- Replaced the gantry motors with internal-encoder motors to improve travel consistency
- Substantially modified the radar imaging software to improve image quality and scan speed
- Moved orchestration between the mmWave Studio laptop and the motor-control Raspberry Pi from SSH automation to a TCP socket-based protocol, reducing uplink timing variability
- Designed and built the BLE-connected metal detector wand from scratch
- Added the infrared camera stream and object detection pipeline
- Added the visible-light facial recognition features
- Designed and implemented the user-facing operator dashboard
SmartTin
Accountability tool for nicotine pouch users
SmartTin is a product-intent project for a pocket-sized, app-controlled locking container that detects and counts opening events and locks itself based on a user-defined schedule. The device is intended to help users of nicotine pouches reduce their consumption by providing accountability and control over access to the product.
Hardware
- ESP32-C3-Supermini dev board
- 3D-printed enclosure with a worm-gear locking mechanism driven by an N20 gear motor
- Magnetic reed switch to detect opening events
Next Steps
The next iteration will swap the ESP32 for an nRF52-series microcontroller to reduce power consumption and improve BLE performance, and will move to a custom PCB to shrink the size and improve manufacturability. It will also trade the cylindrical form factor for a rectangular one to simplify the locking mechanism and reduce the overall size of the device.
FitnessSlot
Exercise randomizer
A device I built for personal use that displays a random exercise from a list each time it's turned on, introducing an element of variability to my fitness habits and breaking up long work sessions with brief exercise using the Pomodoro method.
Hardware
- ESP32-C3-Supermini dev board
- LCD display
- Battery and power switch
The ESP32 runs a simple Arduino IDE program that tracks which exercises have already been shown on each pass through the list, to reduce repetition, and randomly selects a new exercise from the remaining list each time the device is powered on.
Coil Gun
Electromagnetic projectile launcher
A fun little physics demo project I built in college. The coil gun is a simple electromagnetic projectile launcher that uses a coil to accelerate a ferromagnetic projectile down a barrel. It uses 4 9V batteries to charge a bank of 8 4700µF capacitors, then quickly releases their energy through the coil to induce a magnetic field that propels the projectile.
The gun is operated by a 3-position switch that toggles between idle, charging, and firing states, and features an LED indicator that lights up when charging begins and gradually dims as the capacitor bank charges, going dark when the gun is ready to fire.
Credit: This project was inspired by the book "15 Dangerously Mad Projects for the Evil Genius" by Simon Monk.
HippocampusTX.com
Business website with self-serve content management
I built a simple website for a local business, HippocampusTX.com, that lets the non-technical owner curate the site's content themselves, without ever needing to modify the code.
- Google Calendar integration keeps upcoming events displayed automatically
- Google Drive API integration for conveniently uploading gallery images, banners, and event flyers