Bare-metal K64F Fall Detection and Location System

This repository contains a two-node embedded system developed on the NXP FRDM-K64F (MK64FN1M0) board to detect emergency events and transmit patient location/event data over radio.

The project was originally built as an academic project at Tecnológico de Monterrey and is implemented fully in bare-metal C (no high-level embedded framework).

Project overview

The system is split into two firmware applications:

• Tx (Transmitter)

  • Reads sensors and serial GPS data.
  • Detects emergency conditions (fall/zone alert).
  • Packs and transmits event payloads through an nRF24L01 module.

• Rx (Receiver)

  • Listens for nRF24L01 packets.
  • Displays/stores event information.
  • Generates acoustic alerts for different event categories.

Repository structure

• Tx/ → transmitter firmware project.
• Rx/ → receiver firmware project.
• Each side includes:
  • Sources/ for application/peripheral code.
  • Project_Headers/ for register/device headers.
  • Project_Settings/ for linker/startup/debug settings.
  • FLASH/ and RAM/ auto-generated build folders.

Hardware used

• NXP Kinetis K64F MCU (FRDM-K64F platform)
• nRF24L01 transceiver (Tx/Rx link)
• GPS receiver (UART input, transmitter side)
• On-board/connected accelerometer (event trigger)
• Receiver-side peripherals:
  • 16x2 LCD
  • Buzzer/tone output using timer output compare
  • External I2C EEPROM for event storage

Software architecture highlights

Transmitter (Tx)

• Initializes PIT, ADC, UART, SPI, I2C, accelerometer, and low-power timer.
• Parses GPS data and periodically computes averaged latitude/longitude values.
• Uses interrupt-driven event triggers (accelerometer and RF status).
• Sends 5-byte event payloads repeatedly while an event flag is active.

Receiver (Rx)

• Initializes LCD, RF receiver, timers, I2C memory, and GPIO button interrupts.
• Receives 5-byte RF payloads, decodes date/time/event information.
• Saves events to external memory and allows navigation through stored records.
• Generates different tone patterns for different high-level alert types.

Build notes

This codebase uses auto-generated GNU Make projects (from an NXP/CodeWarrior-style toolchain setup).

Typical generated targets

• Tx/FLASH/makefile builds DispositivoMovil.elf
• Rx/FLASH/makefile builds nrf24l01rx.elf

Toolchain expectations

The generated makefiles reference environment variables such as:

• ARMSourceryDirEnv
• GNU_Make_Install_DirEnv

So building from CLI requires a compatible ARM GCC + make setup with those variables configured the same way as the original IDE/toolchain.

Documentation links

• Project presentation (EN):
  • https://docs.google.com/presentation/d/1O1mpz2Zpg-PNperZPEnL-2zeOvIShckMjRdAIiNy-4w/edit?usp=sharing
• Project presentation (ES):
  • https://docs.google.com/presentation/d/1DdGcfKBSRmUkOVxrM-Q6-cPUrZTwif7XFlaJo-RJAoQ/edit?usp=sharing

License

No explicit license file is included in this repository. If you plan to reuse or distribute this work, add a license or confirm permission with the repository owner.