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.

Step 1: Upload Code to ATtiny Using Arduino

Materials:

Arduino
ATtiny
Wires
10uf Capacitor

int ledpin = 1;
int sensorpin = A1;
int sensorValue = 0;
void setup() {
pinMode(ledpin, OUTPUT);
pinMode(sensorpin, INPUT);
}
void loop() {
sensorValue = analogRead(sensorpin);
if(sensorValue>800 ){
digitalWrite(ledpin,HIGH);
delay(500);
digitalWrite(ledpin,LOW);
delay(500);
}
}

Step 2: Testing the Circuit

Material:

Arduino
Led
ATtiny
10kΩ resistor
Velostat

const int ledPin = 3;
const int flexPin = A0;
int value; 

void setup(){
  pinMode(ledPin, OUTPUT); 
  Serial.begin(9600);
}
void loop(){
  value = analogRead(flexPin); 
  Serial.println(value); 
  delay(100);                     
}

Step 3: Making a More Sensitive Pressure Sensor

Materials Needed:

Velostat
Conductive Fabric
Insulated Fabric
Thread

The middle layer is a piece of Velostat. The two outer layers are made of normal insulated fabric. Putting conductive strips on the outer layer makes it less resistive when being pressed. Then stitch them together and make sure the layers not close to each other in a normal state.