Open ECG Shield
An open-hardware single-lead ECG shield built around the AD8232 analog front end, designed for STM32 Nucleo boards.
Implementation
This started as a way to get biomedical-adjacent hardware experience without needing lab-grade equipment. The shield carries an AD8232 analog front end, RA/LA/RL electrode leads, and an onboard 12-bit ADC readout path into an STM32 Nucleo board over SPI. Firmware samples at 250 Hz, applies a simple moving-average filter, and streams raw samples over USB serial to a small Python plotting script — there's no onboard display or storage.
Architecture
Signal path: electrodes → AD8232 analog front end (with right-leg drive for noise rejection) → STM32 internal ADC → DMA buffer → USB CDC serial. The board is a two-layer design in KiCad, deliberately kept simple to stay hand-solderable. All KiCad source files and the Gerbers used for the fabricated batch are in the repository.
Technologies
Known limitations
- This is explicitly not a medical device — no regulatory testing, no clinical validation. It's an educational instrumentation board.
- Single-lead only; multi-lead would require a redesign of the analog front end section.
- No onboard storage or display — a host computer is required for every session.
Members
- Sujin Oh
- Jiho Park
- Yuna Kim