For my midterm assignment, I made a Tshirt for people threatened by a heart attack, called Life lamp.

When the patient is suffering a heart attack, they will have the following signs:
Chest discomfort;
Discomfort in other areas of the upper body;
Shortness of breath;
Others like dizziness, fatigue, lightheadedness, clammy skin, cold sweat, etc.

Therefore, it is hard for them to cry for help. The patients have a common gesture when they are under attack: pressing their chest hard. For Life Lamp, the lamp is attached to the Tshirt. When the victim is suffering a heart attack and press their chest unconsciously, the light will be on. People around this patient will be notified and can help him/her.

Documentation: (Instructables Link: http://www.instructables.com/id/Life-Lamp/)

Demo