Dextrack is a Garmin watch face that shows last hour of blood glucose readings, obtained from Dexcom share API.
Please make sure to check the official Dexcom app before making bolus or eating decisions!
Currently only Garmin Forerunner 245 is supported.
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Last blood glucose reading obtained from Dexcom share.
This shows a message (instead of a glucose level) when the last reading is more than 10 minutes old.
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Current time and date
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Last hour of glucose levels, plotted in a graph.
- Blue line: 200 mg/dl
- Red line: 80 mg/dl
- Gray line: in the middle, 140 mg/dl
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Indicates when the last reading was done, as reported by Dexcom. "-1m" in the screenshot means the shown bg level (132 mg/dl) was read by Dexcom 1 minute ago.
When this number (ignoring the minus sign) is less than 5, you don't need to check your phone or Dexcom device for a more recent reading, as Dexcom reads every 5 minutes.
When this number (ignoring the minus sign) is larger than 5, then it's possible that your phone or Dexcom device will show a more recent reading.
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Indicates when the next request to Dexcom share will be done, to read more recent numbers.
An important limitation to be aware of is Garmin SDK requires at least 5 minutes between HTTP requests. This means once we get the recent numbers from Dexcom share, we have to wait at least 5 minutes before requesting bg levels again.
In most cases, the number you will see here will be 5 or less. However in some cases, to catch up with recent readings without too much delay, Dextrack waits more than 5 minutes before reading bg levels.
For example, suppose we requested bg levels at 14:08, and the most recent reading was done at 14:05. We will show 3-minute-old bg level in (1). If we keep reading new bg levels every 5 minutes, we will always show 3-minute-old data.
So in this case we wait 7 minutes instead 5. This means we will miss the reading at 14:10, but starting from 14:15 we will always show the most recent reading, with only a few seconds delay.
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Blood glucose change rate, based on the last two readings.
"-0.3/m" in the screenshot means that between the last two readings, the bg level was dropping 0.3 mg/dl per minute.
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Watch battery level
When there is an error and during the login sequence, (1) shows a message on what the device is doing, and a number in parens for when the next update will be done.
Dextrack is currently not available on Connect IQ Store, as it currently has no way of configuring Dexcom username, password, and share server to use (based on location). See development section below for details.
This will be fixed soon, and you will be able to install and configure it like any other watch face in Connect IQ Store.
To install Dextrack on your watch, you first need to get your account id. This is easily done by running this command after cloning the git repo: (requires Python 3)
$ ./tools/get_account_id.py <your Dexcom username> <your Dexcom password>
This tool will print a line with 36 characters. This is your Dexcom account id.
Copy this, and create the file source/Secrets.mc with contents:
const DEX_ACCOUNT_ID = "<your Dexcom account id>";
const DEX_PASSWORD = "<your Dexcom password>";
Now you can compile the project as usual (see Garmin's tutorial), and copy
the generated file (the one with extension .prg) to your watch (e.g. to
Primary/GARMIN/APPS in Forerunner 245).
If you are in the US, update "shareous1" in get_account_id.py and
source/Consts.mc files to "share2".
I spent hours but failed to add a settings page to allow configuring Dexcom username, password, and share server. Any help on this would be appreciated.
Once we have a settings page I will publish Dextrack on Connect IQ Store.
Dextrack would not be possible without xDrip developers' heroic effort to hack a Dexcom app and reverse engineer the Dexcom share API.
- xDrip
- Dex CGM app (not open source) is what I used on my watch before writing Dextrack.