Feeding data from Android phone to Bangle.js continuously?

Hi! This is something that's been a frustration for me for a while. Basically Gadgetbridge is big on privacy, so much so that they will never add any internet connectivity to it (although you could build it in yourself).

Since Gadgetbridge has the Bluetooth connection open you're also a bit stuck for Bluetooth comms. My personal wish would be have a WebView running in Gadgetbridge that has access to send/receive from Bangle.js - but given the lack of internet access that's not an option.

I'd been talking to Andreas (one of the lead developers) about this and he is willing to try and add something, but it seems that inter-process comms in Android can also be a bit insecure so it's actually a bit tricky.

So right now I think you have a few options - ordered by how hard they are :)

• Easiest (IMO) is display a notification from your app. Gadgetbridge should then pick that up and pass it to the Bangle, where you can get it really easily.
  
• You could make your phone advertise the data over Bluetooth, and then Bangle.js can pick it up with 'NRF.requestDevice' - that's not related to the connection so won't be an issue, but the data is effectively public for anyone listening for Bluetooth devices
  
• You could make Bangle.js connect to your phone (the phone will already be connected to Bangle.js, but you can have a connection the other way too!) - and you could add a Bluetooth service to your phone for the xDrip+ - but honestly this way seems a lot more painful.