SE-10 sensor detects when no motion?

Hi,

Could anyone help me?

I bought a PIR motion sensor from here: http://proto-pic.co.uk/pir-motion-sensor

I've wired it up as stated with a pull up resistor on the alarm pin

but when I test it I get some very random readings even though nothing is causing it to detect motion???

Bellow shows what 30 seconds looks like. NOTE I've set a delay for 200 milli seconds in-between each reading

1 = HIGH = no motion 0 = LOW = Motion detected

111111111100010101111111001111111111110 111111111110101111111111111111111111010 111111000011111001111111111100011111111 11111000110011111111111111111110

Notice how many times it says it detects motion but in fact nothing was there?!!

I can't understand why this is :( I've check my wires are in the right places, given it 10 seconds to prepare and everything but no matter what I do it still doesn't work as it should.

Can anyone help I'm totally stuck,

Many thanks in advance :)

Here's the simple sketch I'm using to test it

int alarmPin = 2;
int alarmValue = 0; //sensor value

void setup () {
  Serial.begin (9600);
  pinMode(alarmPin, INPUT);
  delay (10000); // it takes the sensor 2 seconds to scan the area around it before it can detect infrared presence. 
}

void loop (){
  alarmValue = digitalRead(alarmPin);
  Serial.println (alarmValue);
  delay(200);
}

It is not detecting motion. It is apparently detecting temperature, or, to be more specific, infrared radiation emitted by warm things, presumably a person ( other than zombies ).

Are there any warm objects within its apparent "field of view" ?

The other possibility, is a weak or erratic electrical connection in your circuit.

Have been experiencing the same unreliable readings as others. Have found that if you power the sensor from A5 Pin set HIGH rather than the normal 5v source the readings are more reliable. I undertand the power is more consistant.