A quick and simple overview of a DIY closed loop during a proof of concept bolus test. This system is based on the Open Source software by Nate Racklyeft (for a full overview of this software, see Episode-8 of the Type 1 diabetes tech series "Are We There Yet...in T1D Tech?" located on the Nightscout Foundation YouTube channel). (This video is intended as a demonstration of proof of concept and not meant for medical therapy.)