Versatile Bio Sensor Guide: Blood Volume Pulse (BVP)
Understanding the BVP sensor on the Versatile Bio
What it measures
BVP is a method of detecting heart beats by measuring the volume of blood passing the sensor in either red or infrared light. From BVP, you can calculate heart rate and heart rate variability (HRV).
Research Applications
Psychology, neuroscience, human factors, user experience, market research, physiology, biomechanics, sports, kinesiology, etc.
How to use
The BVP sensor consists of a small clip that is attached to the end of a finger (but not the thumb). This clip contains an infrared light and a LED that shines a light into the skin, then a sensor measures the intensity of the reflected light , corresponding to blood volume.
If a signal is not visible after placing the sensor, try repositioning. There are two possible wavelengths (red corresponging to the use of LED light and near-IR corresponging to the use of infrared light) which can be toggled for better results. Keep the hand still for proper recording.
Note: BVP sensors are not designed for long-term use in a single location. Plan to change the location of the sensor every 2-4 hours to maintain normal circulation at the sample site.
The BVP sensor is not designed for participants that weigh less than 35 kg (77 lbs). For smaller participants the finger sensor may not fit properly, causing unreliable pulse detection.
Note that fingernail polish and artificial nails may interfere with data collection.
See the detailed instructions that came with the device for more info.
How to clean
The BVP sensor includes elaborate cleaning instructions. Please see these directions first.
To clean and disinfect the sensor, do the following:
- Disconnect the sensor from the Versatile Bio.
- Use Clinell Universal Wipes (For more information, please refer to the following link: Cleaning and Storage Biosignal devices).
- Let it dry before using.
- Autoclave is not recommended, as steam sterilization can damage electronic components.
- Do not immerse the device or the sensor in any liquid.
Connector on Versatile Bio
Visualization filters
To access the data visualization filters, right-click on the signal display in SennsLite or SennsLab.
Under "Notch-Filter" we recommend setting this to the preset matching your country's AC frequency (presets exist for USA/Japan at 60 Hz, and Europe at 50 Hz).
Under "Other Filter" click "enabled"
Set filter type to "Bandpass"
Set High (Hz) to 10 Hz
Set Low (Hz) to 0.5 Hz
Type is "Butterworth"
Order set to 4
Output data
The BVP is reported in µV and will show a deflection and peak with every heartbeat.
Interbeat Interval (IBI) is the time interval between each heartbeat. Heart rate variability (HRV) is a calculation of the changes in the IBI between consecutive heartbeats.
For more information
Shaffer, F., & Ginsberg, J. P. (2017). An Overview of Heart Rate Variability Metrics and Norms. Frontiers in Public Health, 5. doi: 10.3389/fpubh.2017.00258
Felix, Jens, Wolf, & Martin. (2012, November 21). An Efficient Algorithm for Automatic Peak Detection in Noisy Periodic and Quasi-Periodic Signals. Retrieved from https://www.mdpi.com/1999-4893/5/4/588/htm
Janković D., Stojanović R. (2017) Flexible system for HRV analysis using PPG signal. In: Badnjevic A. (eds) CMBEBIH 2017. IFMBE Proceedings, vol 62. Springer, Singapore