How to use background mode operation of Kenek Edge for overnight recording.


This content is for the Kenek Edge pulse oximeter.


Intended Use

The Kenek Edge pulse oximeter by LionsGate Technologies (LGThealth) is an iOS app (available from Apple App Store) and audio-port finger sensor (available from Amazon) for spot-checking blood oxygen saturation (SpO2) and heart rate.  The device should only be used while the user is not moving and not engaging in vigorous activity. 


The Kenek Edge pulse oximeter is not a medical device and is not intended or available for sale for medical or clinical use by physicians or patients.


What is Background Mode?

When you are working with an app on your Apple device, it is in foreground - the display, touch inputs, various buttons, and device resources like networking are all directed to that app.  Any other apps that are running - but not visible - are considered in background.  Apps may be put into background by hitting the Power button (blanking the screen) or by opening another app without closing the app currently in use.


NOTE: Some devices and iOS versions support multi-tasking, allowing more than one app to be in foreground simultaneously.  That case is not discussed here.


When in background, most apps stop operating.  Certain apps can continue to operate in background, particularly those that are downloading from the network, using the audio output, or performing some other operations that do not require user interaction.


From v2.4.0 onward, Kenek Edge continues operating when it is put into background mode.  This means that the red light in the finger sensor will remain lit and measurements will continue to be made, even if they are not displayed on the screen.  If put into background while recording, Kenek Edge will continue to record until it is closed or put into foreground and recording stopped.


NOTE: If an app in foreground uses audio (e.g. Spotify, YouTube, Phone), it may take over the audio port, stopping Kenek Edge from operating.  Even after closing the app using audio, Kenek Edge operation may have not resume until Kenek Edge is brought back into foreground and Oximeter restarted.


Why Use Background Mode?


There are three main reasons for using Kenek Edge in background mode - all involve recording data:

  1. Blank the screen of the Apple device to reduce drain on the battery and extend device operation period
  2. Use another app while Kenek Edge is recording
  3. Avoid data loss when the screen automatically blanks/locks or screen is touched accidentally


Putting Kenek Edge in background mode by blanking the screen (pressing the Power button, or waiting for auto-lock to take over the device), reduces the amount of power used by Kenek Edge.  The majority of the battery drain from use of most apps (including Kenek Edge) is the display screen.  The brighter the screen is, the more battery power is consumed.  Turning down the brightness saves battery and extends the life of the iPhone before recharging is required.  


Turning OFF the brightness can extend battery life dramatically.  


The other benefits of putting Kenek Edge in background mode depend on your uses.  Blanking the screen or putting another app in foreground avoids accidental touching of the screen affecting Kenek Edge recording.  Switching to another app - such as a browser - allows you to use the Apple device for other purposes while continuing to record your health data.


NOTE: Putting another app in foreground that uses the audio system may cause Kenek Edge to stop recording.  As long as the red light appears in the sensor, you can assume that Kenek Edge is continuing to record correctly.


Recording in Background Mode


To record in background mode on Kenek Edge:

  • Start the Kenek Edge app (v2.4.0 or later)
  • Click on Oximeter in the main menu
  • Plug in the sensor and insert your finger to see your current HR and SpO2 measures
  • Make sure that the length of recording time is set to the desired length by clicking the clock icon in the upper right  
    • The default time is 8 hours but can be set from 1 second to 24 hours
  • On the Oximeter screen, when your HR/SpO2 numbers are shown, click the Record symbol (REC in circle)
  • Click the Power button on the top or right side of your Apple device to blank/lock the screen

You are now recording in background mode.  You can confirm that Kenek Edge is still running by checking that the finger sensor's red light is still on (removing your finger should not cause Kenek Edge to stop recording).


If you are using your iPhone, you will see a red bar across the top with the name "Kenek Edge", indicating that it is running in background.



To stop recording, take the following steps and then confirm that Kenek Edge has been working in background by checking the data:

  • Do not remove your finger from the sensor
  • Unlock the Apple device screen and bring Kenek Edge back into foreground (click on app icon or find in app list)
  • Confirm that measurements are still being shown and the recording countdown at the top of the screen is running
  • Click on the Stop symbol (square in circle)
  • Go to main menu and click on History
  • Review the latest item in the History list
    • Confirm that the length of recording is correct
    • Confirm that the date on the item is correct
    • Confirm that the number of data values is as expected
  • Export the data to yourself via email (see this article for details)
  • Confirm that the data shows measurements during the period that Kenek Edge as in background (see this article for details)


There are additional ways to invoke background recording such as starting another app - these are not covered here.


Events Disrupting Background Operation


Background operation can be disrupted by certain events on your Apple device.  In those cases, Kenek Edge will continue recording but the recorded data will show null values.  You can tell if background operation has been disrupted by checking if the red light in the sensor has gone off.To re-enable the sensor (without restarting recording), simply bring Kenek Edge back into foreground.

Typical events that may require re-enabling the sensor by foregrounding the app:

  • Incoming phone call (whether answered or not)
  • Alarm going off
  • Audio notifications

To ensure background mode is not disrupted, consider turning on Do Not Disturb or Airplane modes.


Extended or Overnight Recording


The Kenek Edge pulse oximeter can record measurements of SpO2 (blood oxygen saturation) and pulse rate. For more details read this article on how to record measures, change the period of recording, and to export data or this article for tips on extended or overnight recording.