http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

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Arduino Basics: PIR Sensorsby frenzy on February 16, 2011

Table of Contents

Arduino Basics: PIR Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro:   Arduino Basics: PIR Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 1:   Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 2:   Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 3:   Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

File Downloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Step 4:   Further Projectse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

Author:frenzyI'm the QA engineer here at instructables. I make cool projects in between testing instructables.com to make sure it works awesomely. Give me your bugs!

Intro:  Arduino Basics: PIR SensorsWelcome to the next installment of Arduino Basics!

This instructable will teach you how to use a PIR sensors with the arduino, and we wil build a simple motion detector!

Step 1: SuppliesFor this instructable you will need the following:

1 arduino (with protoshield to make life easy)1 LED of any color1 PIR sensor from Parallax (you can find these at most radio shacks)Solid wire to hook it up

Step 2: SetupThe wiring is pretty simple, the PIR sensor has screen printed: + - out

Hook the + to 5v, - to ground and out to pin 7

The take the LED and put power to pin 8 and ground to ground.

If its confusing, take a look at the pictures!

http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

Step 3: CodeThis code is lifted from the arduino.cc site here, the code I used is also attached.

/** //////////////////////////////////////////////////* //making sense of the Parallax PIR sensor's output* //////////////////////////////////////////////////** Switches a LED according to the state of the sensors output pin.* Determines the beginning and end of continuous motion sequences.** @author: Kristian Gohlke / krigoo (_) gmail (_) com / http://krx.at* @date: 3. September 2006** kr1 (cleft) 2006* released under a creative commons "Attribution-NonCommercial-ShareAlike 2.0" license* http://creativecommons.org/licenses/by-nc-sa/2.0/de/*** The Parallax PIR Sensor is an easy to use digital infrared motion sensor module.* (http://www.parallax.com/detail.asp?product_id=555-28027)** The sensor's output pin goes to HIGH if motion is present.* However, even if motion is present it goes to LOW from time to time,* which might give the impression no motion is present.* This program deals with this issue by ignoring LOW-phases shorter than a given time,* assuming continuous motion is present during these phases.**/

///////////////////////////////VARS//the time we give the sensor to calibrate (10-60 secs according to the datasheet)int calibrationTime = 30;

//the time when the sensor outputs a low impulselong unsigned int lowIn;

//the amount of milliseconds the sensor has to be low//before we assume all motion has stoppedlong unsigned int pause = 5000;

boolean lockLow = true;boolean takeLowTime;

int pirPin = 7; //the digital pin connected to the PIR sensor's outputint ledPin = 8;

///////////////////////////////SETUPvoid setup(){ Serial.begin(9600); pinMode(pirPin, INPUT); pinMode(ledPin, OUTPUT); digitalWrite(pirPin, LOW);

//give the sensor some time to calibrate Serial.print("calibrating sensor "); for(int i = 0; i < calibrationTime; i++){ Serial.print(".");

http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

delay(1000); } Serial.println(" done"); Serial.println("SENSOR ACTIVE"); delay(50); }

//////////////////////////////LOOPvoid loop(){

if(digitalRead(pirPin) == HIGH){ digitalWrite(ledPin, HIGH); //the led visualizes the sensors output pin state if(lockLow){ //makes sure we wait for a transition to LOW before any further output is made: lockLow = false; Serial.println("---"); Serial.print("motion detected at "); Serial.print(millis()/1000); Serial.println(" sec"); delay(50); } takeLowTime = true; }

if(digitalRead(pirPin) == LOW){ digitalWrite(ledPin, LOW); //the led visualizes the sensors output pin state

if(takeLowTime){ lowIn = millis(); //save the time of the transition from high to LOW takeLowTime = false; //make sure this is only done at the start of a LOW phase } //if the sensor is low for more than the given pause, //we assume that no more motion is going to happen if(!lockLow & millis() - lowIn > pause){ //makes sure this block of code is only executed again after //a new motion sequence has been detected lockLow = true; Serial.print("motion ended at "); //output Serial.print((millis() - pause)/1000); Serial.println(" sec"); delay(50); } } }

You can see from the code, the sensor first calibrates itself and then watches for movement. When it detects movement, the blue light goes on. You can watch the serialmonitor to see how long the movement lasts.

http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

File Downloads

pir.pde (3 KB)[NOTE: When saving, if you see .tmp as the file ext, rename it to 'pir.pde']

Step 4: Further ProjectseAfter these steps you have a very simple motion detector. From here you can use the PIR sensor to trigger events (like a siren or a text message that someone is in yourroom).

I just chose to use it to protect my stunnaz from blue light fearing monsters. It seems to work so far....

Please post your PIR sensor projects below and stay tuned for even more Arduino Basics!

http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

Related Instructables

PIR MotionSensor Tutorialby adafruit

ArduinoControlledMotion Sensorby LemonSlice

Squirt -Arduino, motionactivated watercannon byJonathan Robson

PIR AlarmArduino MotionSensor (withEncasing) bychuck4747

Keychaincamera with PIRmotion detectorcontrolled byArduino chip(Photos) byjanisalnis

Basics of theArduino(Duemilanove)by vishalapr

Comments

20 comments Add Comment

 USmarineforces says:  Oct 15, 2011. 4:52 AM  REPLYits a nice project sir and very impresive. but sir' i have a question ahm im working with a project that uses wireless senors for security systems with anaddressable alarm. can you tech me how these things well be built?

 diy_bloke says:  Dec 10, 2011. 1:01 AM  REPLYAs frenzy has not replied yet, I am already going to ask you to be a bit more specific. Are you interested in just connecting wireless sensors or in buildingthe entire system. In that case, what do you mean with 'adressable alarm'.

Just a question out of interest (forgive me if I am completely off): are you by any chance Filipino? :-)

 darrenervine says:  Apr 12, 2011. 8:49 PM  REPLYhow do you get this to send a txt message?I have made a motion activate camera and I am looking to get it to send me a text message or email when a picture is taken...any thoughts?thanks

 Computothought says:  Feb 25, 2011. 1:59 PM  REPLYGoing to do that on my pc. Just have to try it.

 bertus52x11 says:  Feb 16, 2011. 11:04 PM  REPLYDid you get a new identity recently, or is this your standard Arduino outfit?Anyway, always good to read the basics...

 Ghost Wolf says:  Feb 17, 2011. 11:41 AM  REPLYNo you got it wrong you see he was trying to make arduinos less nerdy but.........it had the opposite affect :I

 frenzy says:  Feb 17, 2011. 2:11 PM  REPLYthe arduinos go WOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

 Ghost Wolf says:  Feb 17, 2011. 6:14 PM  REPLY>.> that's was she said

(see i can come up with great comments too)

 frenzy says:  Feb 23, 2011. 5:59 PM  REPLY

http://www.instructables.com/id/Arduino-Basics-PIR-Sensor/

 Ghost Wolf says:  Feb 24, 2011. 7:30 AM  REPLYSooooooooooo you like driving people crazy?

 bertus52x11 says:  Feb 17, 2011. 1:54 PM  REPLYMmm, on second thoughts, I guess you're right!

 Ghost Wolf says:  Feb 17, 2011. 6:16 PM  REPLYIt's a great project if you can make light up sunglasses though

 account3r2 says:  Feb 18, 2011. 8:48 PM  REPLYif you are using fritzing, can you send me the download for the pir sensor?

 frenzy says:  Feb 23, 2011. 5:56 PM  REPLYthere is no download although adafruit has one in her fritzing tutorials.

i just used the basic component with 3 pins and labeled it

 lynne123 says:  Feb 21, 2011. 8:48 AM  REPLYHey frenzy,Great tutorial - very well explained.I could see how a heat sensor and arduino could be used for a project I have been working on. I got the parts but am woefully underexperienced to put ittogether. I am trying to get a thermal array sensor to run a small motor.I'm stuck. Got any suggestions on where to go for help?

 account3r2 says:  Feb 18, 2011. 8:26 PM  REPLYare you using fritzing?

 mhkabir says:  Feb 18, 2011. 11:50 PM  REPLYYes he is.

 maewert says:  Feb 17, 2011. 7:35 AM  REPLYDo you recommend we put a 220 ohm resistor between pin 8 and the LED to limit the current?

Best Wishes

 frenzy says:  Feb 17, 2011. 2:12 PM  REPLYIf you want to be the most correct about it yeah. I didn't and it probablly won't blow the led out but for something more precise, definitely.

 rtty21 says:  Feb 17, 2011. 6:14 AM  REPLYNice new glasses! awesome tutorial too!