Vital Sign Monitor

Overview

The goal of the project is to design and implement a device that monitors vital signs of a human body. Four major vital signs that the project focuses on are:

  • Temperature

  • Electrocardiogram (ECG)

  • Pulse rate

The design comprises two separate devices connected to each other via Bluetooth Low Energy. The hardware board developed consisting of all the sensors will measure the vital signs while the application hosted on the PC will collect information and show it to the user. The main user group that we target are doctors or trained professionals.

Hardware Block Diagram

The following are the key hardware components in this project:

  1. ECG Sensor - AD8232

  2. Infrared Temperature Sensor - MLX90614

  3. Power Management IC - BQ25570

  4. Boost Converter - TLV61220

  5. EFR31BG13 - Microcontroller

  6. Custom made Inverted F Antenna

  7. LCD Screen -LS013B7DH03

  8. Load Switch - SN74LVC1G66DBVR

  9. On board 8MB flash - MX25R8035FM1IL0


Board Designed

The board was designed and assembled completely from scratch by our team. We made some mistake in the schematic and it was rectified using a wire (As you can see in the pictures)

Software Flow Diagram

Sensor Sampling State Diagram

The sensor sampling state diagram is shown on the right. The user can select between Temperature and ECG measurement using the push button.

  • If the user presses the Push button once, Temperature measurement is selected.

  • If the user presses the Push button twice, ECG measurement is selected.

After selecting which measurement to take, the state machine goes through these states:

  1. Power ON the sensor.

  2. Take measurement.

  3. Send BLE indication.

  4. Power OFF the sensor.


BLE State Diagram

The BLE state machine works as follows:

  1. Will be advertising if not connected to any device.

  2. Once a connection is established it will go to a connected state.

    1. If the client disconnects the state machine goes to disconnected state and then to advertising.

    2. If there is data to send, the state machine will send notifications to the connected device.

  3. If connection is closed during any state the state machine puts the software in the advertising mode .


Power Analysis

Detailed power analysis done for the board can be found in the report.