Emotibit - 16+ biometric data streams:
- PPG (3-wavelength) to derive heart rate, heart rate variability, respiration, oxygen saturation, hydration and (we believe) much more! - useful information
- EDA/GSR (electrodermal activity / galvanic skin response): reflects sympathetic nervous system responses that are driven by cognitive and emotional arousal
- 9-axis IMU (accel, gyro, mag) to derive movements, activity, gesture, rotation, and cardinal direction. - maybe can measure micro-movements
- Body temperature to assess health as well as emotional reactions.
@Aarushi Raheja - plot the test results on the tests page.
05/07/23 - Understanding the different sensor data streams.
Exploration methodology:
- What sensors do we have?
- What information does it give? What are the units?
- What do we expect the above to be in an individual that is resting for each sensor? (use research papers)
Interesting read:
https://www.scientificamerican.com/article/pinocchio-s-arm-a-lie-detector-test/#:~:text=Lying is also often accompanied,pressure%2C faster breathing or sweating.
- the brain works harder when we lie. It becomes difficult to perform usual tasks
PPG:
-
Heart rate:
- Typical Range: 60-100 beats per minute (bpm).
- Heart rate tends to increase when people lie, as part of the body's stress response. This is because the [sympathetic nervous system](https://med.libretexts.org/Bookshelves/Anatomy_and_Physiology/Anatomy_and_Physiology_(Boundless)/14%3A_Autonomic_Nervous_System/14.3%3A_Functions_of_the_Autonomic_Nervous_System/14.3A%3A_Sympathetic_Responses#:~:text=maintaining sexual arousal.-,EXAMPLES,the pupils%2C and causing perspiration.) becomes more active during stress, which can lead to an increase in heart rate.
-
Heart Rate Variability:
- It is the measure of the variation in time between each heartbeat
- An indicator of the heart's ability to respond to different physiological states and stressors.
- It is measured in milliseconds (ms).
- Typical Range: Higher HRV is associated with better cardiovascular fitness and stress resilience. HRV decreases with age.
- HRV may decrease when someone is lying. Lower HRV is often associated with stress or anxiety, as it indicates that the body is in a less relaxed state. When the sympathetic nervous system is activated, it can result in a more regular interval between heartbeats, which is reflected in lower HRV.
-
Respiration:
- Males and females: 12 to 20 breaths per minute.
- Lying elevates the heart rate. No particular number found
-
Oxygen saturation: SpO2
- Measure of the amount of oxygen-carrying hemoglobin in the blood relative to the amount of hemoglobin not carrying oxygen.
- It is usually measured as a percentage (%).
- Typical Range: 95-100%.
- No significant and noticeable change when lying.
-
Hydration:
- Not a direct measure.
- No significant and noticeable change when lying.
EDA/GSR (electrodermal activity / galvanic skin response): reflects sympathetic nervous system responses that are driven by cognitive and emotional arousal
- emotional response: capacitance
9-axis IMU:
- Accelerometer: Measures linear acceleration in the X, Y, and Z directions. It can be used to detect movement, orientation with respect to gravity, and sudden changes in motion (like impacts).
- Gyroscope: Measures angular velocity around the X, Y, and Z axes. This is used to detect rotation and is especially useful for tracking changes in orientation and for stabilizing in motion.
- Magnetometer: Measures magnetic fields in the X, Y, and Z directions. It's essentially an electronic compass and can be used to determine the heading relative to the Earth's magnetic North.
While obtain relevant information is hard and this would be an add-on. We can potentially use the IMU for monitoring the following:
- Micro-Movements: When people lie, they might exhibit small involuntary movements due to nervousness. A 9-axis IMU could potentially detect these micro-movements using the accelerometer.
These 2 are harder to implement
- Posture Changes: Changes in posture or body orientation might also be associated with stress or nervousness during lying. The IMU could be used to detect shifts in posture by analyzing accelerometer and gyroscope data.
- Hand Movements: Sometimes when people lie, they might exhibit different patterns of hand movements. A 9-axis IMU attached to the wrist could potentially monitor for patterns in hand movement that are associated with lying.
Body temperature:
- Temperature: 36.5 to 37.5 degrees Celsius (97.7 to 99.5 degrees Fahrenheit)
- Skin temperature may drop as a stress response. But anxiety may cause the skin temperature to rise. No definitive direction.
Polar: @Aarushi Raheja
Yet to read up and analyze ideally using the same exploration framework for consistency
Things to consider while test on people.
- Healthy people between the age groups of 20-45.
- Account for gender.
- Should not have breathing problems
Story.
physiological signal predictors for lying
To be placed in tests as well. @Aarushi Raheja
Before exercise:
after:
This is just for your reference atm, we can move these to an appendix.
- PPG red - these 4 could be HRV
- PPG IR -
- PPG green -
- EDA - Electrodermal Activity
- SCR AMP - Skin Conductance Response Amplitude
- SCR RIS - Skin Conductance Response Rise time
- SCR FREQ - Skin Conductance Response Frequency
Raw data packet architecture
TIMESTAMPPACKET##DATAPOINTSTYPETAGVERSIONRELIABILITYPAYLOAD
Have some prelim code for measuring GSR, temp, and PPG (IMU can be integrated with the next iteration, I also have my reservations about the temperature sensor.)