rdsteed/pancreabble

Send OpenAPS status updates to a Pebble watch via Bluetooth.

pancreabble

Send OpenAPS status updates to a Pebble watch via Bluetooth.

Rationale

To monitor an OpenAPS artificial pancreas system in real-time, a typical setup looks like:

Raspberry Pi/Intel Edison -> network -> Nightscout server -> network -> smartphone
                                                                     |
                                                                     -> smartwatch
                                                                     |
                                                                     -> laptop

In the best case, you're somewhere like a home or office, where your Pi/Edison has already been configured to connect to the wifi. When that's not possible, you can enable a personal hotspot on your phone (until your phone dies, at least).

But in many cases (on a plane, on a long cycling or hiking trip, overseas, underground), you don't have internet, and the whole beautiful constellation of network hops fizzles away. In those cases you should use something like Pancreabble.

Raspberry Pi/Intel Edison -> Bluetooth -> Pebble watch

Using it in your loop: notifications

1. Format your loop state as a subject and message, and send them to the Pebble as a notification:

openaps use pebble notify "`python pebble_subject.py`" "`python pebble_message.py`"

(This assumes you've written pebble_subject.py / pebble_message.py to summarize the relevant bits of your loop state in the way you want.)

1. Take off the watch band, leave your Pebble on the "Notifications" screen, and whoa you just added an e-ink screen to your APS:

Using it in your loop: Urchin CGM

1. Pair the Pebble with your phone, and use your phone to install Urchin.

2. Open the Urchin settings page in the Pebble app on your phone. Configure the graph and layout. Under "Update Settings", make sure the frequency is set to "When CGM reading expected".

3. Forget the Pebble/phone pairing, and pair the Pebble with the Pi/Edison using the setup instructions below. (If it was previously paired, you may need to forget and re-pair it.)

4. For accurate display of CGM recency, it is highly recommended to add a report which reads the CGM clock. Here's what that might look like for Dexcom:

openaps report add monitor/dex-clock.json JSON cgm ReadDisplayTime

1. At the end of your loop, use format_urchin_data to prepare the data, and send_urchin_data to send it:

# You'll want to generate your own loop summary to show in the status line.
echo '{"message": "loop status at '$(date +%-I:%M%P)': copacetic"}' > urchin-status.json

openaps report add urchin-data.json JSON pebble format_urchin_data \
  monitor/dex-glucose.json \
  # Make sure you've read the CGM display clock earlier in your loop:
  --cgm-clock monitor/dex-clock.json \
  # ...and called whatever generates your loop summary message:
  --status-json urchin-status.json

openaps report invoke urchin-data.json

# Consider making this a report, too
openaps use pebble send_urchin_data urchin-data.json

See openaps use pebble format_urchin_data --help for more options.

Setting the Pebble clock

It's a good idea to set the Pebble clock to match the Pi/Edison once per loop:

openaps use pebble set_time

Seemingly correct setup instructions for Raspberry Pi

1. Install BlueZ and libpebble2.

   # I assume it's something like:
   sudo apt-get install bluez
   sudo pip install libpebble2
   

2. Open Settings -> Bluetooth on your Pebble, unpair any phones, and leave it on that screen.

3. Initialize Bluetooth, find the Pebble's Bluetooth MAC address, pair to it, bind it to a virtual serial device:

hciconfig # it's down
sudo hciconfig hci0 up
hciconfig # it's up

systemctl status bluetooth.service # it's inactive
sudo systemctl start bluetooth.service
systemctl status bluetooth.service # it's active

sudo bluetoothctl
[bluetooth]# scan on
# ^ find Pebble's MAC address, then you may have to try these a few times:
[bluetooth]# trust <mac address>
[bluetooth]# pair <mac address>

sudo rfcomm bind hci0 <mac address>

1. Install Pancreabble, add it as an OpenAPS vendor, add a device:

pip install --user git+git://github.com/mddub/pancreabble.git

# in your openaps directory:
openaps vendor add pancreabble
openaps device add pebble pancreabble /dev/rfcomm0
openaps use pebble notify "hello" "testing"

# result:
{
  "subject": "hello",
  "message": "testing",
  "received": true
}

1. Add these lines to /etc/rf.local so that Bluetooth is initialized and the Pebble is paired and bound to /dev/rfcomm0 on boot:

hciconfig hci0 up
systemctl start bluetooth.service
rfcomm bind hci0 <mac address>

Caveats

• When your Pi/Edison is off the grid and thus doesn't have access to NTP, unless you've cleverly worked around the Pi's lack of RTC or configured the Edison's RTC, the times reported by that device will also be wrong. (If you do manage to configure the Edison's RTC, would you be so kind as file an issue explaining how you did it?)

Coming soon

• Package for PyPI
• Auto-configure/pair/bind