Secret Diary Alarm Using Piezo Speakers
Description:
A basic & primitive security system for secret diaries. Using a photocell embedded in a diary to detect if and when a diary is opened, and a piezo speaker as an alarm.
Material:
bread board
arduino
photocell
piezo speaker
wires
Code:
int potPin = 0; // select the input pin for the potentiometer
int speakerPin = 7;
int val = 0;
void setup() {
pinMode(speakerPin, OUTPUT);
Serial.begin(9600);
Serial.println("ready");
}
void loop() {
digitalWrite(speakerPin, LOW);
val = analogRead(potPin); // read value from the sensor
//val = val*200; // process the value a little
//val = val/2; // process the value a little
for( int i=0; i<.0001; i++ ) { // play it for 50 cycles
digitalWrite(speakerPin, HIGH);
delayMicroseconds(val);
digitalWrite(speakerPin, LOW);
delayMicroseconds(val);
}
}
(1 vote)
