We have taking the idea a step forward by creating an alarm system that utilizes two sensors, the photocell and the ultrasonic range finder. Both sensors are connect to an Arduino UNO that is configured to send bytes to another Arduino UNO. In order to achieve the stream of bytes the Xbee on the Arduino has to be configured to Coordinator API.
The scenario for this project is to keep a valuable object safe from others in a secret place. We therefore set the object inside a closet where the photocell will be calibrated to the light once the door is closed thus the inside, where the sensor is located with the object, is completely dark. A change of the state of the sensor will happen once the door is opened.
Since an intruder can open the door with the outside also dark the sensor will not set off the alarm because there is no change in the light. Due to this issue, the ultrasound sensor is used to determine a change on the position of the object, that we want to keep away of the hand of the enemy. If any of the sensors notice a change the alarm (buzzer) will go off and a tune will play.
The material used:
- (2) Computers
- (2) Arduino UNO
- (2) XBee explorer (and at least one USB-to-mini-USB cable)
- (2) XBee
- (2) Breadboards
- (1) Green LED
- (1) Piezo speaker (buzzer)
- (1) Photocell
- (1) Ultrasonic Range Finder
- (1) Button
- (2) 10kΩ
In order to simplefy it we start with one part of the whole system, the one with the sensors. The following sketch shows all the connections and materials used.
The finnised set up looks like this with the choosen object to be kept save:
The code for the Arduino on this set-up with the sensors:
#define lightPin 0 //define a pin for Photo resistor
#define trigPin 12 //define a pin for the US trigger
#define echoPin 11 //define a pin for the US echo (our input)
//int audioPin = 12; //define a pin for LED
int LDRreading, outputValue, LDRMax = 0, LDRMin = 1023;
String incomingBytes;
boolean Running = false, calibrated = false;
//variables needed for reading distance from US sensor
long duration, distance, durationMax = 0, durationMin = 100000;
void setup()
{
Serial.begin(9600); //Begin serial communcation
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
void loop()
{
while (Serial.available() > 0) {
delay(10); //small delay to allow input buffer to fill
char c = Serial.read(); //gets one byte from serial buffer
incomingBytes += c; //create the word we're receiving
}
//Serial.println(incomingBytes);
if (incomingBytes.startsWith("stop"))
Running = false;
if (incomingBytes.startsWith("start")) {
Running = true;
//if (!calibrated)
calibrate();
}
incomingBytes = "";
if (Running == true) {
LDRreading = analogRead(lightPin); //read the value of the photoresistor
// Serial.print("LED reading is: ");
// Serial.println(LDRreading); //Write the value of the photoresistor to the serial monitor.
//start measuring distance
digitalWrite(trigPin, LOW); //toggle the pin OFF so we're sure we'll have a clean reading
delayMicroseconds(2); //short delay
digitalWrite(trigPin, HIGH); //10 microseconds ON time, that's all the Ultrasound sensor needs
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH); //we read the duration of the sound wave bouncing back from the object
distance = (duration / 2) / 29.1; //we divide it by 2 as the sound wave needs to get to the object and back and again by 29.1 to get centimeters
// Serial.print("Duration is ");
// Serial.println(duration);
// Serial.print("Distance is ");
// Serial.print(distance);
// Serial.println(" cm");
if (duration < durationMin - 30 || duration > durationMax + 30 || LDRreading < LDRMin - 30 || LDRreading > LDRMax + 30) {
// Serial.print("ALARM");
Serial.print('a'); // a from alarm
Running = false;
}
delay(100); //short delay for faster response to light.
}
}
void calibrate() {
LDRMax = 0;
LDRMin = 1023;
durationMax = 0;
durationMin = 100000;
for (int i = 0; i <= 50; i++) {
LDRreading = analogRead(lightPin); //read the value of the photoresistor
//start measuring distance
digitalWrite(trigPin, LOW); //toggle the pin OFF so we're sure we'll have a clean reading
delayMicroseconds(2); //short delay
digitalWrite(trigPin, HIGH); //10 microseconds ON time, that's all the Ultrasound sensor needs
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH); //we read the duration of the sound wave bouncing back from the object
// record the maximum sensor value for LDR
if (LDRreading > LDRMax) {
LDRMax = LDRreading;
}
// record the minimum sensor value for LDR
if (LDRreading < LDRMin) {
LDRMin = LDRreading;
}
// record the maximum sensor value for LDR
if (duration > durationMax) {
durationMax = duration;
}
// record the minimum sensor value for LDR
if (duration < durationMin) {
durationMin = duration;
}
delay(50); //short delay for faster response to light.
}
calibrated = true;
Serial.print('c'); // c from calibrated
// Serial.print("max ldr:"); Serial.println(LDRMax);
// Serial.print("min ldr:"); Serial.println(LDRMin);
// Serial.print("max duration:"); Serial.println(durationMax);
// Serial.print("min duration:"); Serial.println(durationMin);
}
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The other Arduino with the button and the LED looks like this:
Here is the set-up:
And finally the code:
// Here we have the theme-song that will play
// once the alarm goes off.
// At the end you can see the needed methods.
#define NOTE_B0 31
#define NOTE_C1 33
#define NOTE_CS1 35
#define NOTE_D1 37
#define NOTE_DS1 39
#define NOTE_E1 41
#define NOTE_F1 44
#define NOTE_FS1 46
#define NOTE_G1 49
#define NOTE_GS1 52
#define NOTE_A1 55
#define NOTE_AS1 58
#define NOTE_B1 62
#define NOTE_C2 65
#define NOTE_CS2 69
#define NOTE_D2 73
#define NOTE_DS2 78
#define NOTE_E2 82
#define NOTE_F2 87
#define NOTE_FS2 93
#define NOTE_G2 98
#define NOTE_GS2 104
#define NOTE_A2 110
#define NOTE_AS2 117
#define NOTE_B2 123
#define NOTE_C3 131
#define NOTE_CS3 139
#define NOTE_D3 147
#define NOTE_DS3 156
#define NOTE_E3 165
#define NOTE_F3 175
#define NOTE_FS3 185
#define NOTE_G3 196
#define NOTE_GS3 208
#define NOTE_A3 220
#define NOTE_AS3 233
#define NOTE_B3 247
#define NOTE_C4 262
#define NOTE_CS4 277
#define NOTE_D4 294
#define NOTE_DS4 311
#define NOTE_E4 330
#define NOTE_F4 349
#define NOTE_FS4 370
#define NOTE_G4 392
#define NOTE_GS4 415
#define NOTE_A4 440
#define NOTE_AS4 466
#define NOTE_B4 494
#define NOTE_C5 523
#define NOTE_CS5 554
#define NOTE_D5 587
#define NOTE_DS5 622
#define NOTE_E5 659
#define NOTE_F5 698
#define NOTE_FS5 740
#define NOTE_G5 784
#define NOTE_GS5 831
#define NOTE_A5 880
#define NOTE_AS5 932
#define NOTE_B5 988
#define NOTE_C6 1047
#define NOTE_CS6 1109
#define NOTE_D6 1175
#define NOTE_DS6 1245
#define NOTE_E6 1319
#define NOTE_F6 1397
#define NOTE_FS6 1480
#define NOTE_G6 1568
#define NOTE_GS6 1661
#define NOTE_A6 1760
#define NOTE_AS6 1865
#define NOTE_B6 1976
#define NOTE_C7 2093
#define NOTE_CS7 2217
#define NOTE_D7 2349
#define NOTE_DS7 2489
#define NOTE_E7 2637
#define NOTE_F7 2794
#define NOTE_FS7 2960
#define NOTE_G7 3136
#define NOTE_GS7 3322
#define NOTE_A7 3520
#define NOTE_AS7 3729
#define NOTE_B7 3951
#define NOTE_C8 4186
#define NOTE_CS8 4435
#define NOTE_D8 4699
#define NOTE_DS8 4978
#define melodyPin 3
//Mario main theme melody
int melody[] = {
NOTE_E7, NOTE_E7, 0, NOTE_E7,
0, NOTE_C7, NOTE_E7, 0,
NOTE_G7, 0, 0, 0,
NOTE_G6, 0, 0, 0,
NOTE_C7, 0, 0, NOTE_G6,
0, 0, NOTE_E6, 0,
0, NOTE_A6, 0, NOTE_B6,
0, NOTE_AS6, NOTE_A6, 0,
NOTE_G6, NOTE_E7, NOTE_G7,
NOTE_A7, 0, NOTE_F7, NOTE_G7,
0, NOTE_E7, 0, NOTE_C7,
NOTE_D7, NOTE_B6, 0, 0,
NOTE_C7, 0, 0, NOTE_G6,
0, 0, NOTE_E6, 0,
0, NOTE_A6, 0, NOTE_B6,
0, NOTE_AS6, NOTE_A6, 0,
NOTE_G6, NOTE_E7, NOTE_G7,
NOTE_A7, 0, NOTE_F7, NOTE_G7,
0, NOTE_E7, 0, NOTE_C7,
NOTE_D7, NOTE_B6, 0, 0
};
//Mario main them tempo
int tempo[] = {
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
9, 9, 9,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
9, 9, 9,
12, 12, 12, 12,
12, 12, 12, 12,
12, 12, 12, 12,
};
//Underworld melody
int underworld_melody[] = {
NOTE_C4, NOTE_C5, NOTE_A3, NOTE_A4,
NOTE_AS3, NOTE_AS4, 0,
0,
NOTE_C4, NOTE_C5, NOTE_A3, NOTE_A4,
NOTE_AS3, NOTE_AS4, 0,
0,
NOTE_F3, NOTE_F4, NOTE_D3, NOTE_D4,
NOTE_DS3, NOTE_DS4, 0,
0,
NOTE_F3, NOTE_F4, NOTE_D3, NOTE_D4,
NOTE_DS3, NOTE_DS4, 0,
0, NOTE_DS4, NOTE_CS4, NOTE_D4,
NOTE_CS4, NOTE_DS4,
NOTE_DS4, NOTE_GS3,
NOTE_G3, NOTE_CS4,
NOTE_C4, NOTE_FS4, NOTE_F4, NOTE_E3, NOTE_AS4, NOTE_A4,
NOTE_GS4, NOTE_DS4, NOTE_B3,
NOTE_AS3, NOTE_A3, NOTE_GS3,
0, 0, 0
};
//Underwolrd tempo
int underworld_tempo[] = {
12, 12, 12, 12,
12, 12, 6,
3,
12, 12, 12, 12,
12, 12, 6,
3,
12, 12, 12, 12,
12, 12, 6,
3,
12, 12, 12, 12,
12, 12, 6,
6, 18, 18, 18,
6, 6,
6, 6,
6, 6,
18, 18, 18, 18, 18, 18,
10, 10, 10,
10, 10, 10,
3, 3, 3
};
// constants won't change. They're used here to
// set pin numbers:
const int buttonPin = 2; // the number of the pushbutton pin
const int ledPin = 13; // the number of the LED pin
// variables will change:
int buttonState = 0; // variable for reading the pushbutton status
int song = 0;
void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
Serial.begin(9600);
pinMode(3, OUTPUT);//buzzer
}
void loop() {
while (Serial.available() > 0) {
char c = Serial.read();
if (c == 'c')
digitalWrite(ledPin, HIGH);
if (c == 'a') {
//sing the tunes
//sing(1);
//sing(1);
sing(2);
}
}
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed.
// if it is, the buttonState is HIGH:
if (buttonState == HIGH) {
// turn LED on:
Serial.print("start");
}
}
void sing(int s) {
// iterate over the notes of the melody:
song = s;
if (song == 2) {
Serial.println(" 'Underworld Theme'");
int size = sizeof(underworld_melody) / sizeof(int);
for (int thisNote = 0; thisNote < size; thisNote++) {
// to calculate the note duration, take one second
// divided by the note type.
//e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
int noteDuration = 1000 / underworld_tempo[thisNote];
buzz(melodyPin, underworld_melody[thisNote], noteDuration);
// to distinguish the notes, set a minimum time between them.
// the note's duration + 30% seems to work well:
int pauseBetweenNotes = noteDuration * 1.30;
delay(pauseBetweenNotes);
// stop the tone playing:
buzz(melodyPin, 0, noteDuration);
}
} else {
Serial.println(" 'Mario Theme'");
int size = sizeof(melody) / sizeof(int);
for (int thisNote = 0; thisNote < size; thisNote++) {
// to calculate the note duration, take one second
// divided by the note type.
//e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
int noteDuration = 1000 / tempo[thisNote];
buzz(melodyPin, melody[thisNote], noteDuration);
// to distinguish the notes, set a minimum time between them.
// the note's duration + 30% seems to work well:
int pauseBetweenNotes = noteDuration * 1.30;
delay(pauseBetweenNotes);
// stop the tone playing:
buzz(melodyPin, 0, noteDuration);
}
}
}
void buzz(int targetPin, long frequency, long length) {
digitalWrite(13, HIGH);
long delayValue = 1000000 / frequency / 2; // calculate the delay value between transitions
//// 1 second's worth of microseconds, divided by the frequency, then split in half since
//// there are two phases to each cycle
long numCycles = frequency * length / 1000; // calculate the number of cycles for proper timing
//// multiply frequency, which is really cycles per second, by the number of seconds to
//// get the total number of cycles to produce
for (long i = 0; i < numCycles; i++) { // for the calculated length of time...
digitalWrite(targetPin, HIGH); // write the buzzer pin high to push out the diaphram
delayMicroseconds(delayValue); // wait for the calculated delay value
digitalWrite(targetPin, LOW); // write the buzzer pin low to pull back the diaphram
delayMicroseconds(delayValue); // wait again or the calculated delay value
}
digitalWrite(13, LOW);
}
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Videolog:
Part 1;
Part 2:
