Hi,

I am using a PIR Sensor for security purposes. I have used this code but when there is nothing is covering the sensor it will still detect something that is there. Please help.

void loop()
{
SensorEvent.attachInt();
SensorEvent.detachInt();
SensorEvent.loadInt();

XBee.setMode(XBEE_ON);
delay(200);
if (SensorEvent.intFlag & SENS_SOCKET7)
{
XBee.println("A person is detected");
Utils.blinkLEDs(1000);

}
delay(500);
XBee.close();
SensorEvent.intFlag = 0;
SensorEvent.attachInt();
}

Best Regards.

Hi WhoUseMyName,

take into account that the PIR is a very sensitive sensor with a wide input range, so any movement in the surroundings may trigger it. You may select the position H with the jumper so the interruption is triggered only once when continuous movement is detected.

Regards.

Hi libelium_dev,

Is it possible to calibrate the sensor so that it will cover a fixed range to detect motion. Or is it possible to program it to send message through zigbee so whenever motion is detected for more then 10 seconds, it will send a message.

Best Regards.

Hi WhoUseMyName,

I'm afraid it is not possible to calibrate the sensor. The second option is feasible, with the sensor configured to keep the output high at continuous detection, after receiving the interruption you may keep polling the sensor and use the millis() function or the RTC to control the time elapsed and send the XBee message.

Regards.

Hi libelium-dev,

I used this code to detect motion for an amount of time. If it senses motion it will light an LED, if the motion stops the LED will stop. The LED will keep blinking even though there is no movements. I've tried putting the waspmote inside a box. It will still detect movements even inside the box. Is it something wrong with my code or is the PIR Sensor faulty?

This is my code,

int calibrationTime = 10;
long unsigned int lowIn;
long unsigned int pause = 5000;
boolean lockLow = true;
boolean takeLowTime;

void setup()
{
XBee.setMode(XBEE_ON);
SensorEvent.setBoardMode(SENS_ON);

XBee.println("Init RTC");
RTC.ON();
RTC.setTime("11:08:08:02:16:10:00");

XBee.print("calibrating sensor");
for(int i=0; i < calibrationTime; i++)
{
XBee.print(".");
delay(1000);
}
XBee.println(" done");
XBee.println("SENSOR ACTIVE");
delay(50);
}

void loop()
{
if(SensorEvent.readValue(SENS_SOCKET7) == 1)
{
Utils.setLED(LED0, LED_ON);
if(lockLow)
{
lockLow = false;
XBee.println("---");
XBee.print("motion detected at ");
XBee.print(millis()/1000);
XBee.println(" sec");
XBee.println(RTC.getTime());
delay(50);
}
takeLowTime = true;
}

if(SensorEvent.readValue(SENS_SOCKET7) == 0)
{
Utils.setLED(LED0, LED_OFF);
if(takeLowTime)
{
lowIn = millis();
takeLowTime = false;
}
if(!lockLow && millis() - lowIn > pause)
{
lockLow = true;
XBee.print("motion ended at ");
XBee.print(millis()/1000);
XBee.println(" sec");
XBee.println(RTC.getTime());
delay(50);
}
}

}

Best Regards.

Hi WhoUseMyName,

I've tested your code and it works pretty well.

The PIR sensor may keep retriggering for a few seconds, so you should wait a little bit. Also, it is a very sensitive sensor, you will have to completely cover it with a solid object to make sure it does not detect anything.

Regards.