ECE-GY6483-F22_Just-Breath-Challenge

Group Member (Ordered by Last Name Alphabetically)

Irving Fang - zf540 Xing Fang - xf757 Jesse Inouye - jai9962 Peiyu Tian - pt2203

Project Overall Description

In this project, we utilize a Piezoelectric Ribbon Sensor to detect the breathing of a baby.

Workflow

When the Ribbon is put on the baby, the user needs to press the User Button to start the monitoring. When a lack of breathing for 10s has been detected, the LCD Display will display a warning message and produce an audio warning through the Buzzer. The user will need to press the Reset Button to stop the warning and press the User Button again to restart the workflow.

Details

About the Piezoelectric Ribbon Sensor

Unlike regular disk-shaped Piezoelectric sensors, the sensor we used is a ribbon/strip that can wrap around a baby's chest. It will produce a current when there is a force applied to it AND the force is causing it to be stretched and then un-stretched. Our board would detect such a current and issue a warning if no such current has been observed for 10 seconds.

Some advantages of this sensor of choice:

1. The sensor is not simply a force sensor, and would not produce current if it's simply being pressed or being stretched for an extended period of time. The only motion that can make this sensor produce a current is stretching it and then un-stretching it. This provides great robustness for detecting the motion of breathing. As we know, babies would roll around and may cause the sensor to be held against a wall/side of a cradle. However, constant pressing this sensor will not produce current and, therefore, would not produce a false positive.

2. This sensor can be easily incorporated into a comfortably-wearable woven stripe as it does not require direct skin contact. Thus, we believe it can be adapted to a comfortable product that users would not find intrusive.

Topics Used in This Project

1. Interrupt and ISR to kick start the workflow when a button is pressed
2. Multithreading for displaying different message
3. ADC with the voltage producing sensor
4. GPIO for reading sensor reading and driving buzzer.
5. Finite State Machine for organizing the workflow

Peripherals

Onboard Peripherals

• Green LED to indicate that monitoring is ongoing and no abnormality has been detected.
• Red LED to indicate that we have detected an abnormality, that is, we believe the baby has stopped breathing.
• User Button to start the workflow after the sensor is placed on the baby by triggering a interrupt.
• LCD Display
  • Before the User Button is pressed, it will display a welcome message and the instruction to start the device
  • After the User Button is pressed, it will display a breathing effect indicating that monitoring is ongoing and no abnormality has been detected
  • When an abnormality is detected, it will display a warning message
• Reset Button to reset the board back to the state before the User Button is pressed. Users need to press the User button again to restart the workflow

Self-Purchased Peripherals

• KY-012 Active Buzzer to produce an audio warning when an abnormality has been detected.

  • Connected to pin PF_6 and GND.
  • Price: roughly $0.7 for one. Link

• Piezoelectric Ribbon Sensor to detect for breathing.

  • Connected to pin PC_3 and GND.
  • Price: $24.95 for one. Link

Project Structure

• main.cpp contains the main logic and workflow of the project.
• display_helpers.cpp/display_helpers.h contains all the helper functions that display different messages for different scenarios of the workflow, including instructions and warnings.
• drivers folder contains official drivers for the ST board we use.

Future Improvement

• We planned to add an attention message like "Please Adjust the Strip" when the device is put on the baby and turned on, but no breathing has been detected. However, we noticed that this might further complicate our main logic, so we decided not to include it in the final project submission.

• Originally, the sensor is connected to PA_0, and it would produce a much more intuitive reading in the sense that when there is no stretching and un-stretching, the voltage reading is all 0, and we detect such a motion, the voltage reading is positive. However, since PA_0 is connected to the User Button, we have to switch to another pin that has ADC connected. And on all the other pins the readings are inverse: motion will produce a zero voltage reading, while no motion would result in fluctuating positive readings. So far, we are unable to resolve this issue.