I Built an Artificial Pancreas

Sarah Withee


Quick Rundown of How Carbohydrates Work

  1. You eat carbohydrates
  2. Your body breaks them into glucose and fructose
  3. Glucose goes into blood
  4. Pancreas sees extra glucose, makes insulin
  5. Insulin binds to glucose
  6. Your cells use glucose+insulin for energy

Quick Rundown of Diabetes

Diabetes - When that process doesn't work


Type 1 - Insulin-making cells destroyed

Type 2 - Resistant to what you do make


There are other rarer types too

Quick Rundown of Diabetes

In US, measured in mg/dL (milligrams per deciliter)


Normal people:        70-99 mg/dL

Diabetics aim for:  80-130 mg/dL


After eating, the number goes up



Why Diabetes Is Hard


Carb ratio: X carbs/1 unit (1/100 mL) of insulin


Carbs absorb within 15-20 mins

Insulin starts absorbing in 30 mins,

    can take up to 5 hours


Glucose too high?

     Slowly bad circulation problems, organs slowly die

Glucose too low?

     Shaking, sweating, weakness, could land in hospital



Insulin pump

Technology to the Rescue!

So... What's This Artifical Pancreas?

OpenAPS - Open Artificial Pancreas System


  • Linux-based IoT Device
  • Has 915 MHz transceiver
  • All open source-based software

CGM sends values over Bluetooth to xDrip+

Stored in Nightscout

Values load into OpenAPS rig

Rig sends RF to pump to dose differently

Live Demo (sorta)!

URL:  clicky

"Whoa... is this safe?"

tl;dr  yes

"Can't it be hacked?"

tl;dr  anything can be hacked, but it's too obnoxious/slow to do

"Is it annoying to carry all this around?"

tl;dr  kinda, but worth it



Where's It At?

Instructions:  https://openaps.readthedocs.io


OpenAPS - github.com/openaps/oref0


Nightscout - https://github.com/nightscout/cgm-remote-monitor


xDrip+ (Android) -



Loop (iOS) - https://github.com/LoopKit/LoopKit

SSHing into "Sar-borg"

I Built an Artificial Pancreas

By Sarah Withee

I Built an Artificial Pancreas

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