Sensor Based Embedded System Design

I am starting a fresh embedded-system build that must reliably read data from several sensors—specifically temperature sensors, motion sensors, and physiological channels for heart and respiration. The goal is a complete, production-ready solution: hardware selection, low-level firmware, and a clean interface that lets the rest of my product stack pull real-time data without hassle.

Here’s what I need you to handle:
• Architecture and component selection around an appropriate microcontroller or SoC
• Schematic and PCB layout for the sensor front-end and core logic
• Bare-metal or RTOS-based firmware in C/C++ (your recommendation) that acquires, filters, and time-stamps each sensor stream
• A simple serial, SPI, or BLE protocol—whichever fits best once we review constraints—for downstream data access
• Validation documents: test plan, compiled binaries, pinout tables, and concise user notes so my team can reproduce results

Skills required:

Microcontrollers (nRF52 / ESP32)
I²C, SPI, BLE
Sensor integration (PPG, IMU)
Power management (Li-ion charging)
Basic firmware architecture

need to work on:

Wire sensors
Write firmware
Bring up the board
Send data over BLE
Help debug power issues

I’ll supply any preferred vendors, enclosure dimensions, and compliance targets as soon as the project kicks off. Show me examples of past sensor interfacing work and tell me how you’d break the milestones; that will help us get moving quickly.