# BI‑Vital History

Version / Year	Key upgrades	Photo/Rendering
V 1.0 (≈ 2003 – 06)	• Bluetooth Classic v1.1 (≈ 10 m) • 8‑bit MCU • 1‑lead ECG – inverting amp only • Coin‑cell • First fully custom PCB
V 2.0 / 2.1 (≤ 2007)	• Bluetooth Classic v2.0 (≈ 20 m) • 8‑bit MCU • Maxim‑Bessel (V 2.0) / Butterworth (V 2.1) ECG filters with galvanic isolation • Coin‑cell in re‑housed Polar strap
V 3.0 (2007)	• Switched to ZigBee 2.4 GHz (20–40 m) • 8‑bit MCU (same core) • Refined Maxim‑Bessel ECG front‑end • Coin‑cell in re‑housed Polar strap
V 4.x (2008 – 11)	• ANT link (+ SPA receiver) • 16‑bit MSP430 MCU • ECG + 3‑axis accelerometer + temperature sensor • Coin‑cell in re‑housed Polar strap • 8 MB Flash Memory
V 5.0 (2018)	• Dual‑mode ShockBurst + BLE 4.2 (nRF51) • 32‑bit STM32L476 MCU • 9‑DoF IMU (BNO055) + BME280 environment + microphone • Li‑Po + µUSB charging • Custom 3‑D‑printed case • 128 MB NAND flash
V 5.1 (2019)	• Major/Minor PCB fixes • Production of a higher number of units
V 5.2 (2025)	• USB‑C + BLE name laser‑marked on PCB • STM32 L476 (1 MB flash on‑chip) • Same sensor suite • Transparent 3‑D print, SMD Li‑Po & SMD vibration motor • 128 MB NAND • Robust battery protection, easier assembly
V Pro (up‑coming) (Evalboard 2024)	• New state of the art µC (nRF53/54) • Smart sensor ICs: IMU (BHI360 + BMM150), Environment (BME688), ECG & BioZ IC (MAX3001) and onboard Electrodes • Skin Temperature Measurement (MLX80632) • E-Ink Display, 3-Buttons Interaction • Plux Sensor Extension • Neural Network Acceleration Chip • 512 MB NAND • NFC, Matter, Thread