Loop Follow

Loop Follow is an open-source DIY (do-it-yourself) iPhone app that combines your T1D’s display information and alerts into a single easy-to-use interface.

This code was originally developed by Jon Fawcett. He has turned over management of the app to the Loop and Learn team. We are happy to respond to bug reports or feature requests.

The release history is stored on the GitHub website associated with the open-source repository.

Loop Follow can get its data from Dexcom Share or Nightscout.

  • If you use Dexcom Share, you won’t see the details on the right side of the image below, but you’ll still get your glucose records and alerts.
  • If you use Nightscout and the Loop or iAPS app, then you can configure what you want to see on the right side of the display.

Using Loop Follow

Each of the features below is selectable – you decide whether to use them.  Additionally, many features are adjustable because YDMV (your diabetes may vary).

  1. Scrollable/scalable graph display with BG, IOB, COB, Basal, and Bolus, plus Loop status, Loop Prediction, and the General NS Care portal info.
  2. Override DND (Do Not Disturb) and system volume for all alerts.  Includes extensive alert settings including:
    Snooze, Pre-snooze, edit existing Snooze, and Snooze All Until.
  3. Standard Low/High, Urgent Low/High, and Missed Reading alerts.  High will have a persistence option that’s still to do, e.g., High for x minutes.
  4. Fast Drop/Rise alerts with BG limits, e.g., Trigger fast drop only when under a BG where it’s an issue.
    SAGE/CAGE reminder alerts for x hours before the change.
  5. Not Looping with BG limits alert so you can trigger the alert only if under or over a BG range.
  6. Missed Bolus alert.
  7. Calendar entries to use watch complication with BG, arrow, delta, COB, IOB, and Minutes-Ago (if old reading).
  8. Background silent audio to keep iOS from killing the app (which is why it can’t go into the App Store for a simple download).
  9. Badge displays the current BG value on the app icon.
  10. New: Carbs today, under Information Display Settings
  11. New: Pull down on the glucose value to force a refresh from Nightscout (iPhone only – does not work on Mac)
  12. New:  When adding a Nightscout site, NS Status says “Checking”, “Site Not Found”, “Token Required”, “Invalid Token”, or “OK”. You may need to quit and restart app if you change NS settings in order to force the update.
  13. New:  The default scheme within Xcode is set to LoopFollow by default. [Not selecting Loop Follow within Xcode was one of the most common build errors.]

Videos are available to help you understand the older Loop Follow features.  There is also a Loop Follow build video, but the build process has changed so much, please don’t watch the video as it is unlikely to help you build and will definitely add to your confusion.

Building Options

Loop Follow can be built using either the GitHub-Browser Build or the Mac-Xcode Build method.  A paid Apple Developer Account is required.

GitHub-Browser Build

You can build Loop Follow on any computer using the GitHub-Browser Build method in LoopDocs.

Run Loop Follow on your Computer

Now that you’ve built using the GitHub-Browser method, if you want to run Loop Follow on your computer, you need to install the TestFlight app on your computer. The TestFlight app shows the same set of builds and uses the same installation procedure as shown in LoopDocs for installing apps on a phone from TestFlight; just do it on your computer.

Mac-Xcode Build

Loop Follow can be built using a Mac and the Build-Select script.   Go to Loop and Learn/Build-Select Script and choose Build Loop Follow.

Run Loop Follow on your Mac

  1. Build Loop Follow to your Mac.
  2. Click stop to close the running app.
  3. On the left side of Xcode, click on the Folder icon.
  4. Click to open the LoopFollow folder list.
  5. Click to open the LoopFollow/Products folder.
  6. Right-click (or Cntl-click) on “Loop Follow.app” and select Show in Finder.
  7. Drag the Loop Follow.app icon to your Applications folder in finder (see Duplicate Loop Follow app discussion below).
  8. From Mac system settings/notifications, scroll down to Loop Follow and enable notifications with the options you want. For instance, Badge app icon will allow the BG reading to display on the icon.

Duplicate Loop Follow app?

For existing Loop Follow users, if CustomTypeOne previously sent you a beta-test version of the Loop Follow app via TestFlight, building Loop Follow yourself will result in having a duplicate Loop Follow app because the first one was built with CustomTypeOne’s Apple Developer ID rather than yours.

On your computer:

  • You should have an existing Loop Follow app in your Applications folder.
  • This new installation from TestFlight does not ask if you want to replace your app – you get a second app, Loop Follow 2.app, in your Applications folder.
  • Delete the original Loop Follow.app and rename the TestFlight version from Loop Follow 2.app to Loop Follow.app.
  • Subsequent installations from TestFlight overwrite the app.  Your settings are maintained regardless of the app name.

On your iPhone:

Search for both apps, transfer to the one that is new (won’t have any entries for data source yet), and then delete the old one.

Authentication Token

For those who secure their Nightscout site with an authentication/access token, you’ll need to get a token for Loop Follow too.  Your token requires “readable” as a role. (That will make sense when you read the docs at the link.)

Main vs. dev

Loop Follow users should build Loop Follow-Main.  New features are tested in the dev branch. Once it has been thoroughly tested, it will be merged into Main.

Pro Tips

Loop Follow can be used by Loopers too.  Many Loopers love the slick look of Loop Follow’s dashboard as a quick check on their current status and daily results.  Since the Looper won’t need the Loop Follow alarms, turn off Background Refresh, as it consumes a significant amount of battery power.


Volunteers Welcome

If you want to contribute, please make your pull request against the dev branch. If you notice a bug please write an issue report.

Open Source DIY

This is a DIY open-source project that may or may not function as you expect. You take full responsibility for building and running this app and do so at your own risk.

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