Photoplethysmography (PPG)
C# 7.3+ · Teslasuit XR5+ · SDK 2.5.1+
What is PPG?#
Photoplethysmography (PPG) is a non-invasive optical technique that measures blood-volume changes in microvascular tissue: a sensor emits light into the skin and measures how much is absorbed or reflected by blood vessels. It is widely used in fitness and medical wearables to monitor heart rate and other cardiovascular parameters in real time. For the sensor details, sampling rate, and how the signal becomes metrics, see Concept: Biometry (PPG). This page focuses on how PPG data is exposed through the C# SDK.
PPG in the Teslasuit API#
PPG is part of the suit's biometry subsystem. A single PPG sensor in the upper-right sleeve produces the signal (see Concept: Biometry (PPG) for sensor specs). In the C# SDK this is accessed through IDevice.Biometry, which exposes an IPpg interface for streaming raw data and reading processed values such as heart rate.
Note: call IPpg.Start before reading data, and check IPpg.IsRunning. Data arrives through the RawUpdated and ProcessedUpdated events, which fire from a background thread.
Key features of the Teslasuit PPG subsystem#
- Raw data streaming: stream raw PPG data (infrared, red, blue, and green channels) in real time for custom signal processing.
- Processed data: heart rate plus a validity flag on each value.
- Event-driven updates: subscribe to raw and processed update events rather than polling.
Description of PPG data#
The subsystem exposes processed heart-rate data plus the raw signal. The physiological meaning of these metrics is covered in Concept: Biometry (PPG). Below are the fields you work with in the API.
Heart rate#
Heart rate (HR) is the number of beats per minute, calculated from the interval between successive beats (the R-R interval). Processed values arrive through the ProcessedUpdated event as IProcessedPpgData, which carries one ProcessedPpgNodeData per sensor node.
Heart rate parameters and explanation#
- Heart rate (HR): beats per minute, calculated for every R-R interval.
- Validity flag: whether the value is measured or extrapolated. During movement, signal artifacts can make direct measurement unreliable, so an extrapolation algorithm estimates HR to keep the stream continuous.
What to read next#
Explore these guides and resources to deepen your understanding and get the most out of Teslasuit PPG features:
Essential API references#
- Biometry reference: Technical documentation for using the Teslasuit PPG subsystem.
- Common types — PPG: Full descriptions of the data types and structures for PPG data.
Practical guides & examples#
- Read heart rate: Stream live heart rate from a PPG node.
Deeper dives & broader concepts#
- Concept: Biometry (PPG): The full conceptual background, including the sensor, LED wavelengths, sampling rate, and calibration.
- Teslasuit Main Concepts: Go back to explore and understand the other Teslasuit subsystems and how PPG fits within the larger suite of technologies.