# 103 - Lumbar Angle Feedback

This app measures the lumbar angle between sensors on the L1 and S1 spine. The angle is compared to a threshold, and feedback is turned on when the threshold is exceeded.

### Nodes Required: 2
- l1_sensor
- s1_sensor (also provides vibration feedback)
  

## Algorithm & Calibration
### Algorithm Information
- None noted.
### Calibration Process:
- None noted.

## Description of Data in Downloaded File
- time (sec): time since trial start
- lumbar_angle (deg): lumbar flexion angle between the two sensors
- lumbar_angle_percentage (%): lumbar angle within the calibrated flexion range
- feedback_threshold (%): threshold for feedback
- feedback_state (int): 1 if feedback is on, 0 if feedback is off
- feedback_enabled (int): 1 if feedback is enabled, 0 if feedback is not enabled
- index of raw sensor data
- AccelX/Y/Z (m/s^2): raw acceleration data
- GyroX/Y/Z (deg/s): raw gyroscope data
- MagX/Y/Z (μT): raw magnetometer data
- Quat1/2/3/4: quaternion data
- Sampletime: timestamp of the sensor
- Package: package number of the sensor
