In a team of two, we created a wearable security alarm that was implemented using the Arduino Uno and MIT App Inventor.
By using an IR sensor we were able to calculate the distance of an attacker approximately 4 feet away. If the sensor were to pick up motion, the alarm would send a signal to the users phone. An app that was designed by my partner would then immediately call the users emergency contact or set off an alarm on the users phone.
My role in the project was to implement the IR sensor and Arduino. Once the sensor detected an attacker, a signal would be sent to the app. This project was the very first project I worked on. It was here that I was introduced to the idea of making an idea become reality. Even thought it was a challenging I got to gain more experience and grow as an engineer.
Below is the code that I designed to program the Arduino:
//define pins
int dist_pin = 0;
//save distance reading
int current_dist = 0;
int sensor_dist= 0;
void setup() {
Serial.begin(9600);
}
void loop() {
//read in the sensor distance
sensor_dist = analogRead(dist_pin);
//convert into cm
current_dist=28250/(sensor_dist - 229.5);
//check to see if there is an accurate reading
//if there is a weird reading i.e negative/ large reading read again
while(current_dist < 0 || current_dist> 500){
sensor_dist = analogRead(dist_pin);
//convert into cm
current_dist=28250/(sensor_dist - 229.5);
}
//for debug, print the values on the monitor
//Serial.print(current_dist);
//Serial.println("cm");
//check to see if the attacker is about 4 feet away
//if yes then set alarm off
if(current_dist < 130){
//set alarm off
Serial.write("alarm");
}
//delay by half a second
delay(500);
}