Project 28 Ultraviolet Sensor to Alarm
1.Introduction
When ultraviolet sensor receives ultraviolet ray up to a certain value, the buzzer rings.
2.Hardware Required
Arduino Board *1
V5 Shield*1
USB Cable*1
Shield V5*1
Buzzer Module*1
Ultraviolet Sensor*1
Dupont Line*Several
3.Circuit Connection
Plug Shield V5 into UNO board and don’t misplace pins to avoid damaging the board.

4.Sample Code
int ON = 11;
// the setup routine runs once when you press reset:
void setup()
{
// initialize serial communication at 9600 bits per second:
pinMode(ON, OUTPUT);
Serial.begin(9600);
}
// the loop routine runs over and over again forever:
void loop()
{
// read the input on analog pin 0:
int sensorValue = analogRead(A0);
int n;
// print out the value you read:
if(sensorValue>=20)
{
for(n=0;n<8;n++)
{
digitalWrite(ON, HIGH);
delay(1000);
digitalWrite(ON, LOW);
delay(500);
}
}
else
{
digitalWrite(ON, LOW);
}
Serial.println(sensorValue);
delay(1); // delay in between reads for stability
}
5.Result
After uploading the codes, you can see when the value is equal to or more than 20, the buzzer rings for 1 second and stop for 0.5 second, circulating 8 times.