Hardware Design Engineer focused on wearable sensor integration and PCB design. This page documents the R&D process, design methodology, and troubleshooting logs for my current hardware projects.

• PCB Design: KiCad (Schematic Capture, Layout, DFM)
• Embedded Systems: nRF5340, STM32WB, BLE Firmware integration
• Analog/Mixed Signal: ECG/EMG AFE designs, Audio/Optical systems
• Instrumentation: Oscilloscopes, Multimeters, Logic Analyzers

An initial prototype of a neural-feedback system for reading movement/muscle data and notifying the user of biomechanical events

• Objective: Design a wireless, multi-channel EMG to enable any user to access every-day movement patterns.
• Key Components: nRF5340 MDBT53-1M SOC, USB, rechargeable Li-Ion battery.

• Design Philosophy: Focus on design validation to improve the form factor in later iterations.
• Debug Log / Lessons Learned:
  • Issue: None yet, awaiting assembly.
  • Future Iteration: Significantly reduce form factor to fit in mechanical housing and support adhesion to various body locations. WIrelessly connect to applications.

• Current Phase: Design verification to ensure functionality before intended final revision.

A compact, wall outlet compatible device for creating dynamic, color changing LED's that travel across the entire length of an LED Strip.

• Objective: Design an audio based system for reading audio signals, deriving the base frequencies, and changing the color of LEDs on the strip.
• Key Components: nRF5340 MDBT53-1M SOC, analog front end, buck converter, LDO.

• Design Philosophy: Focused on filtering out sound for ease of signal processing and FFT analysis.
• Debug Log / Lessons Learned:
  • Issue: Could detect target device when programming, but could not flash to the core.
  • Root Cause: Inadequate pad-to-pour clearance in the initial layout - short between GND and SWDCLK.
  • Resolution: Validated via continuity testing.
  • Future Iteration: Relocate GND via near SWDCLK on MDBT53-1M pads, reduce GND pour coverage near pads.

• Current Phase: Power/digital architecture validated. AFE and firmware validated on breadboard for full LED control. Redesign to relocate via and pour profile.

A compact, low-power wearable device for EMG signal acquisition.

• Objective: Design a small-scale wearable EMG sensor node with integrated BLE for remote monitoring.
• Key Components: STM32 MCU, Custom Analog Front End (AFE), LiPo Battery.

• Design Philosophy: Focused on miniaturization and high SNR for biosignals.
• CAD/Layout:
  
  
  
• Debug Log / Lessons Learned:
  • Issue: Encountered configuration issues when setting up STM32WB through STM32CubeIDE.
  • Root Cause: Inadequate reflow on STM32 during assembly.
  • Resolution: Validated via continuity testing.
  • Future Iteration: Design around reflow, select another chip.

• Current Phase: Architecture validated. Analog AFE performance verified; digital core transitioning for ease of assembly.

I am currently developing a modular reference motherboard for the nRF5340 MDBT53-1M module.

• Goal: To decouple digital bring-up from complex sensor/analog integration.
• Architecture: Core board (MCU/Power) + Carrier board (AFEs/Sensors).
• Expected Outcome: A proven baseline for all future wearable sensor iterations.

• LinkedIn: www.linkedin.com/in/michael-miller-4b3918201
• Email: mmille7497@gmail.com