Cardiorespiratory Monitor uses your Android device's sensors to measure a person's breathing and heartbeat rates. This app goes beyond other heartbeat monitoring apps by using either the device's light and camera with the subject's finger or motion sensors. The motion sensors measure your chest movements! This is also the only heartbeat monitoring app that gives you a sense of the reliability of the measurements.
With the 'motion method' the app takes sensor readings several times each second while the device is resting on the subject's chest. The app makes use of a technology in your device called 'sensor fusion,' which combines the readings of multiple sensors to isolate such variables as linear acceleration, rotation, and gravity. The app monitors the change in angle to determine the breathing and heartbeat rates. Your device must have gyroscopes, accelerometers, and magnetometers and a version of Android that supports these technologies. If you are not sure, you can try one of the free sensor test apps in the Google Play Market and find out. Or, you can first try the free version, CardioRespiratory Monitor Free.
The app shows breathing and heartbeat rates (in bpm), as well as the amplitudes of each. Also shown are plots of the breathing movements and the average movement due to the heartbeat (as angle versus time in arbitrary units). This is the only Android app that measures all these quantities.
With the 'camera+light' method, the app takes multiple images each second while the subject's finger is covering the rear camera and light. First, the finger is placed over the camera and light. When the Start button is pressed, the app reads the camera data for 25 seconds. The light passing through the finger to the camera dims when blood surges through the arteries during each heartbeat. The average interval between the light pulses is equal to the average interval between heartbeats. You can monitor the changing brightness on your device's screen as the readings are taken.
The pro version of the app adds several options not available on the free version. These include the following:
- whether a 'ping' sound is emitted after each round of measurements,
- the number of rounds of measurements,
- whether the measurements are saved to a file,
- whether the results are 'spoken' with your device's text-to-speech capability.
Cardiorespiratory monitor comes in free and pro versions. They are available on the Google Play market:
Screenshot of main screen of pro version of Cardiorespiratory Monitor.
Settings screen of pro version of Cardiorespiratory Monitor.