Gentle reminders for set and sensor change

[mortenfyhn]

I'd like some nice and gentle reminders for when it's almost time to do a set change or sensor change. The pump's version of this is crap, it just gives me an alarm exactly N days after the previous change, so if I did one late at night it'll wake me up. And the alert arrives too late. Instead I want to be gently reminded in advance. Maybe something like this, if I'm supposed to change set/sensor on a given day:

• Morning: Something showing up on the watchface, maybe a timeline quick view [1] or status text on the watchface instead of a buzzing notification
• Then eventually it should escalate to a notification, maybe sometime in the evening, only when there's a risk of forgetting. I don't want a notification for something I am aware of and am about to do, that's just annoying. Maybe 20:00 or something, or when it's perhaps 1 hour left of sensor life.

[1] This is a quick view

[mortenfyhn]

Pebble's own battery reminders could be good inspiration here:

[palmarci]

This is a very good idea, i would have loved this yesterday night. Sensor changes before sleeping is mostly safe if you do a BG calibration before it. But changing the QuickSet is sometimes unlucky and it makes the night a hell. So i think it would also make sense to write this generic and wire in both remaining sensor time and when the reservoir is like 30 units remaining

[mortenfyhn]

Do you find sensor changes at night are fine if you do the calibration during warmup, or does it have to be after warmup is done?
Good point about the units remaining thing. I almost always have insulin left when I change my set, and just try to change it every 3 days regardless of how much is left. The reminder should be both time-based and insulin remaining-based. Maybe with some configurability.

[palmarci]

I usually wait 5-10 minutes after sensor insertion and then do a manual BG reading. Have not had any issues with it, then i go to sleep while it is still warming up.
About the QuickSet, i always leave it in until there is insulin. I guess this is not the recommended way, but personally, no issues.

[mortenfyhn]

Cool, I guess it makes sense that the warmup routine would take the manual BG into account.

[mortenfyhn]

Did some digging, it is as expected possible to get data from the pump about when the sensor will expire, in a more elegant way than checking for sensor change and hardcoding a 7 day timeout. The minimed app shows sensor expiry, so it was kind of guaranteed to be possible.

• 0x0202 Time of Sensor Expiration indicates every 5 min and contains the total sensor lifetime as "10200 minutes" = 170 hours ≈ 7 days.
• 0x101's Sensor EOL is not really useful, see IDD service: Add info from sensor changes Documentation#3 (comment)
• 0x2aaa CGM Session Start Time gives the start time of the sensor
• 0x2aab CGM Session Run Time (read) really has the same info as 0x0202, but as "170 hours" instead of minutes.

So then it's not more complicated than

• sensor expiration = 0x2aaa + 0x0202
• remaining time = expiration - pump time

[palmarci]

Sensor remaining time is already implemented in python: https://github.com/OpenMinimed/PythonPumpConnector/blob/4ed349786885ee004cd8ed26b8250db2703af58b/cgm/misc.py#L113
For the reservoir, i think we need the #22 first

[mortenfyhn]

#22: Not quite, it should be enough to read how much is left. #22 is about combining that with the insulin decay curve to estimate active insulin, which is a bit more work than this requires.

I'm thinking the set change reminder can be something like:

• Reminder on the 3rd calendar day after a set change (changed Monday -> reminder Thursdag)
• Reminder when insulin in reservoir goes below some limit, or estimated time to empty goes below some limit (which we can roughly compute)