PIR Motion Sensor

This is a simple to use motion sensor. Power it up and wait 1-2 seconds for the sensor to get a snapshot of the still room. If anything moves after that period, the 'alarm' pin will go low.

This unit works great from 5 to 12V (datasheet shows 12V). You can also install a jumper wire past the 5V regulator on board to make this unit work at 3.3V. Sensor uses 1.6mA@3.3V.

The alarm pin is an open collector meaning you will need a pull up resistor on the alarm pin. The open drain setup allows multiple motion sensors to be connected on a single input pin. If any of the motion sensors go off, the input pin will be pulled low.

The connector is slightly odd but has a 0.1" pitch female connector making it compatible with jumper wires and 0.1" male headers.

Note: The colors of the wires can vary greatly. Looking at the unit from the top, the middle wire is ground, the left-most wire is the alarm, and the right-most is the power.

PIR Motion Sensor Product Help and Resources

RedBoard Santa Trap

December 25, 2014

A fun holiday project to try for anyone looking to catch Santa on Christmas!

PIR Motion Sensor Hookup Guide

May 5, 2016

An overview of passive infrared (PIR) motion detecting sensors, and how to hook them up to an Arduino.

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
See all skill levels

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

1 Electrical Prototyping

Skill Level: Noob - You don't need to reference a datasheet, but you will need to know basic power requirements.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • NickH / about 15 years ago / 4

    Just wanted to confirm that this is a great sensor. It seems to be most sensitive to motion that is orthogonal to the board (ie straight on.)
    @cloverstreet: I've seen it detect motion reliably up to ~20ft away. There is no need to reset the alarm, it doesn't latch. The alarm pin is debounced (deflapped?) internally, and seems to cycle off on the order of a second or so.
    Also, a slight warning about the datasheet (at least for my unit): If you're not paying attention, and use the three silver pin latches to orient the connector it'll be backwards. As the description says, red is power, brown is ground, and black is alarm.

    • arcflash911 / about 14 years ago / 2

      Hey NickH
      I'm using this to make a key switched 12VDC alarm with an output whooper being fired by this sensor. I'm a parts guy, not an electronics guru. Based on your comments, I'll need a latching relay to keep my whooper going because the sensor will reset after a second or two. Is that right?

  • SlvrSrfr / about 15 years ago / 3

    Using arduino, I had unstable outputs when using the "5V" pin as the power supply pin and the pull-up for the alarm pin.
    Eventually, I used the "5V" pin solely for pull-up (i.e. resistor between "5V" of arduino and alarm pin (black) of motion sensor).
    To power the motion sensor, I tried using a 9V battery which works perfectly. I also tested using the "Vin" pin on arduino and can report stable output, although the detection is somewhat slower than using a pure 9V power supply. The "Vin" pin gives me 4.16V so I am not sure what is happening here.
    So the final pinout is:
    - "Vin" on arduino to Vin for sensor
    - "Gnd" to "Gnd"
    - Resistor between "5V" of arduino and alarm pin of sensor
    - Wire from alarm pin to input pin on arduino
    Hope this helps anyone trying to use this sensor with the arduino board.

    • ahmad / about 14 years ago / 2

      I had the same problem you are describing. I didn't want to use separate power supplies, but I noticed I got much cleaner output from the PIR by swapping out the 10k resistor with a 1000 ohm resistor. I still have both the pull-up resistor and the red wire going to the 5V rail powered by the arduino.
      I'm not sure why this works better, if anyone has any ideas, i'd be interested to learn.

  • tomic / about 15 years ago / 3

    I'd use 10K as pullup resistor. Don't forget, though the PIR sensor runs on +12V, the pullup should go to +5V! The pullup is on the INPUT pin, and the sensor pulls that to ground. (3.3V for 3.3V inputs, etc)
    The sensor will momentarily pull the input to ground when it thinks "something moved". Your software will have to determine what that means.
    What I do is, use Arduino's millisec() function to run a software timer that essentially tells me how much time has passed since someone walked by the sensor. In loop() put this code up near the top:
    if (digitalRead (SENSOR) == LOW) {
    timer= millisec();
    Then when you wanna ask "has someone walked by the sensor in the last 25 seconds?" (for example) you would execute:
    if (millis() - timer < 25000L) {
    Serial.print ("Room is occupied");
    eg. "less than 25000 milliseconds since I saw an event". That's the basic idea anyhoo.

  • Member #34933 / about 16 years ago / 3

    very easy to use.
    used with atmega128
    excellent quality..

  • Member #419229 / about 11 years ago / 2

    I know newbie question but : Would the alarm go off if there is a heater in the room that is not always on/off ???

    Thank you :D

  • c19274 / about 14 years ago / 2

    I futzed around with this one for a couple of projects, but i finally just bought this parallax sensor that is easier to connect, easier to read, and works comfortably off 5V: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2082927_-1<br />
    <br />
    i would rather see sparkfun carry this item or similar, since i get most other things here.

  • MIKLOS / about 14 years ago / 2

    Really easy with this example from Tom Igoe....:
    ..people here can be very confusing...

  • Chris S / about 14 years ago / 2

    Very easy to use.
    Note that the AL pin will go low several times during "initialization". After a few second, it will stop ging low and stay high. If you are going to use this on an interrupt, for example, you will need to wait maybe 10 seconds before initializing it.
    When something does move, the sensor will go low for as long the object is moving and then go high again.
    A 10K pullup will work fine.

  • BT / about 15 years ago / 2

    Anybody know what kind of supply current this thing draws?

  • zouze / about 15 years ago / 2

    if it detects something, how will it stay low?

  • Allen Pitts / about 9 years ago / 1

    Getting wildly intermittent results. Sometimes it works sometimes it doesn't. Tried it wired to the Arduino 5V as in this diagram http://www.allenpitts.com/pir_Sensor.gif And substituted a 9V battery to the sensor. Neither reliable. Would hate to have the security of my home or business reliant on this system.

    Also the instructions above say: 'Note: The colors of the wires can vary greatly. Looking at the unit from the top, the middle wire is ground, the left-most wire is the alarm, and the right-most is the power.' This is unspecific. 'From the top' with the wire output at the bottom or 'From the top' with the wire output on the top. One has a fifty-fifty chance above a reversed hook up and a puff smoke.

  • Member #616477 / about 10 years ago / 1

    what would i hook that up to?

  • Member #132954 / about 10 years ago / 1

    These sensors are way too sensitive. Even when putting a tube around it for focus, there are a ton of false positives. I don't think that I can make anything reliable with these.

  • Member #592040 / about 10 years ago / 1

    Alright, I been volunteering at a School Cafeteria for a few years now and the new soap dispenser has a motion sensor. Unfortunately, the sensor picks up nearly nothing at the moment and there appears to be no way to make it more sensitive as-is.

    Of course I may be wrong, but there are a switch and a button. The switch controls how much soap it dispenses and the button... doesn't appear to do anything. Help much appreciated.

    Any advice?

  • Member #591232 / about 10 years ago / 1

    Does it brake, when I swap AL and Vcc?

  • Member #591232 / about 10 years ago / 1

    Is it that the new version has different cable colors? I have RED + WHITE - BLACK AL

    however I tried the wiring which is suggested here, but it didn't work: 9V Bat + > + 9V Bat - > - 5V > 10k ohm > digital pin x AL > digital x but only reading HIGH

    • Member #591232 / about 10 years ago / 1

      oh great the description says:

      The colors of the wires can vary greatly. Looking at the unit from the top, the middle wire is ground, the left-most wire is the alarm, and the right-most is the power.

      but looking at it from the top left has a + symbol and right the AL

      did I kill it already?!

  • Member #517027 / about 10 years ago / 1

    I get massive numbers of false positives. I do not see any way to tune down the sensitivity. My first thought is to catch one, hold a second, and check for another - maybe this will help. But looking at my current logs I think I will start dropping real positives. humph. Is my RPI timing out on the open collector/interrupt at some point? I kind of doubt it, but who knows. Are these "real" false positives caused by EMI or temperature shift? perhaps my garage door shaking with wind does it, but I kind of doubt it since if I stand there and shake the door with my arm about as hard as I can I do not see the hits.

    Any help?

  • Demo with the PIR Sensor in comparison with the ePIR=> http://youtu.be/xZGYn-oipQc

  • Member #492819 / about 10 years ago / 1


    Does this connector work for this?

  • Member #545262 / about 10 years ago / 1

    please can i know the distances it can cover

  • Member #514293 / about 10 years ago / 1


  • Member #382517 / about 11 years ago / 1

    Sorry if this is a dumb question, but how well do you think it would work at night, anybody? Or do I need an IR sensor for that if there is minimal light from streetlights. for play, not security.

  • Member #481236 / about 11 years ago / 1

    is this sensor easy to interface with a microcontroller? i wanted to get either this one or this one http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2082927_-1, whats the difference?

  • Member #479871 / about 11 years ago / 1

    please, how can i purchase this sensor and order it from (Iraq-Baghdad)??

  • MostThingsWeb / about 11 years ago * / 1

    Excellent little sensor. I agree that it operates better at 9V. A 10K pullup resistor has been working fine.

  • Member #40615 / about 11 years ago * / 1

    The regulator on these is a surface-mount linear regulator, which theoretically is good all the way up to 21 volts or so, as long as you stay within heat limits. These take very little power, and my project had 18 volts handy, so that's what they're getting. It works great.

  • Member #430748 / about 11 years ago / 1

    using this to point a laser at sombody when seen, is there a way to send a specific position?

    • The Doctor Doge / about 11 years ago / 1

      Try an infrared camera module or a CMUCAM

    • Kamiquasi / about 11 years ago / 1

      Nope. While there are some PIR sensors with more than 2 zones, this one only has the pretty standard 2. Moreover, you typically can't read out the individual zones anyway - with the sensor directly outputting a high/low signal to signify 'a' change, but not where that change happened, how big that change was, etc. If you want a specific enough position to actually target somebody, or something, you'll have to start looking at other solutions.

  • MattiasF / about 11 years ago / 1

    I just did a bit of tinkering getting PIR sensors to work at 3.3v and wrote up my findings on a page. With some sensors it's pretty easy to get it to work with 3.3v: http://techgurka.blogspot.com/2013/05/cheap-pyroelectric-infrared-pir-motion.html

  • Member #140033 / about 11 years ago / 1

    Does some one tried it with blueSMiRF? I have no stable read (jumps from 5V to 0V without a reason) from PIR when i connect blueSMiRF silver. Is there known issue?

  • Member #429128 / about 11 years ago / 1

    Trying to get this to work with WIG-11029 the triggerable MP3 player. Not sure where im going wrong. Getting 3.3v off of the mp3 player and hooked to both sides of the trigger inputs as well. reading 0 and 1.1v respectively.

    • Member #40615 / about 11 years ago / 1

      It has a built-in voltage regulator, you will have to jumper past it if you want to run this off of 5 volts or lower. Also be mindful of the pinout. Go by the location of the wires because the color of wires is COMPLETELY inconsistent. (The ones I have don't just have a different order, they don't even have all the same colors...)

  • Member #38182 / about 11 years ago / 1

    What is the usable operating range of this device?

  • Jeroen3 / about 11 years ago / 1

    Does anybody know details about the amplifier circuit on board?

  • Member #389337 / about 11 years ago / 1

    I for this device is very low about that of an LED 12mA, could be why the 10K causes problems. @ about 3.3 V I = 12mA @ 5V I = 23 ma

    thsi is give or take a few mA

  • Member #382760 / about 12 years ago / 1

    I know that normally with this sensor you would use a weak pull up resistor to connect the open collector output to Vcc. However if you wanted to just connect up an LED or other device what is the maximum load that can be drawn through the open collector output? Also is the on board regulator able to handle this?

    • Hi, We will be happy to look into this. However it appears that we don't have access to that information. We will certainly be happy to share any information that we may find. Just contact us at TechSupport@Sparkfun.com

  • Member #378197 / about 12 years ago / 1

    Is there an easy to understand schematic out there for a beginner to understand? So far I have an Arduino UNO, this PIR sensor, a small breadboard, some 10k resistors and jumper wires. I am trying to get an led on pin 13 to come on and stay on until the motion leaves the range of the PIR. So far I have the positive of a 9v battery hooked to the positive of the sensor and the negative of the battery to the negative of the sensor. I have the alarm wire from the sensor hooked to a 10k resistor and then to digitalPin 9 on the UNO. When i checked voltage from between resistor and UNO i had 1-2 volts so i used a couple 330 ohm resistors to get the voltage up to 5 so it would show high on the UNO. My problem is that i cant seem to get the led to come on when motion is detected and go off when it detects nothing. In fact it does just the opposite. Is there something messed up in the code? Ill post the code soon for yall to see. Thanks!

  • Member #40615 / about 12 years ago * / 1

    They are NOT KIDDING when they say the arrangement of wires can vary! I just got one where power is BLACK.

    Also, it is dodgy at 5 volts like everyone says.

    [edit] Now confirmed that jumpering past the 5V regulator lets it run at raw 5V. It's a tricky job though!

    • nanunh / about 12 years ago / 1

      in the picture Alt PIR

      THE WIRES ARE REALLY MESSED UP - here is what worked for me

          Detector Output!!
          5V - REALLY

      • Member #40615 / about 12 years ago * / 1

        Your ordering is correct -- for now. Who knows how long that will stick?

        I just ignored the colors, and went by the ORDER in the datasheet. That worked.

      • nelioneves / about 12 years ago / 0

        I make like http://bildr.org/2011/06/pir_arduino/, but my PIR have the wire like you said. Now, my sensor doesn't work. $9.95 goes to trash.

        • Member #40615 / about 12 years ago * / 2

          Quoth the product page: "Note: The colors of the wires can vary greatly."

          That said, I hooked mine up backwards(at 5V) and didn't kill it.

          When I used the order given in the datasheet, ignoring the colors, it worked.

          Also, look at the picture of the back of the device at the top of the product page. You can see the 3.3 volt regulator on the left side. The wire attaching to that is the +v wire.

  • Richiep / about 12 years ago / 1

    How are you installing these things in the real world? I've been sticking them on walls with thumb tack pins. Would it be safe to use 2 sided tape?

    What are best practices for this sort of thing?

    Thanks Rich

  • Richiep / about 12 years ago / 1

    WARNING - As others have stated in this thread the data sheet is wrong wiring has changed.

    Red - Alarm Brown - Ground Black - 12V

    It's cool if all your sensors or wired one way or the other but I have a dozen sensors with the two configurations mixed together.

  • Member #358927 / about 12 years ago / 1

    I ordered three of these sensors through a supplier in the UK (Hobby-Electronics) and all three are wired different from the images shown on both the sparkfun as on the hobby-electronics website. My three sensors have the red and black wire reversed so the wiring then becomes even stranger than before: - Red: Signal, alert. - Brown: Ground. - Black: Vin (9 volt battery).

    I first tried wiring the sensor as shown on the datasheet and that didn't give a good signal. The output signal became around 2V and remained constant around that value.

    When I reversed the wiring (black to +9V, red as signal) the output signal was as it is supposed to be.

  • Richiep / about 12 years ago * / 1

    Ok, I've successfully used these in other projects and they've worked great. I just ordered a bunch of them and when I hook them up in my new projects they're not working. I'm using the exact same sketch I used in my other projects but I cannot get them to work.

    Here's what I've got

    • Red to 12v using VIN
    • Brown to ground
    • Black with 10K pullup resistor to 5V and to alarm Arduino analog pin 0

    You can see my wiring here example

    This is exactly how I have this set up in my previous functional application and what is described on this page.

    When I open the serial monitor I get repeating 1023 that does not change at all.

    I've tried this on several Arduino boards without luck.

    I'm using Arduino IDE build 1.0.1; I used an older build of the IDE on my previous project version 0022. Seems like this shouldn't be an issue.

    Note that I have tried to get this to work on all the analog ports on several Arduino boards.

    Here is a copy of my sketch.

    // example for the PIR motion sensor SE-10
    int timer = 3000;
    int alarmPin = 0;
    int alarmValue = 0;
    int ledPin = 13;
    void setup () {
    Serial.begin (9600);
    pinMode(ledPin, OUTPUT);  
    pinMode(alarmPin, INPUT);
    delay (2000); // it takes the sensor 2 seconds to scan the area around it before it can detect infrared presence. 
    void loop (){
    alarmValue = analogRead(alarmPin);
    if (alarmValue > 1){
    digitalWrite(ledPin, HIGH);
    digitalWrite(ledPin, LOW);
    Serial.println (alarmValue);
    delay (10);

    Please help!

    Thx Rich

    • Richiep / about 12 years ago / 1

      OK, I found this sketch that that uses digitalRead instead of analogRead that works. And it's more appropriate for my application.


      Not sure why my analogRead isn't working above.

  • Member #341954 / about 12 years ago / 1

    after trying about 3 times with different configurations. the sensor fails to work properly... disappointed to say the least.

  • Just Passing Through / about 12 years ago * / 1

    I just got one of these and the black and red leads are swapped from the photo: the sensor I have has the black on the left and the red on the right. I hooked it up using the instructions on Bildr Tutorial and it stayed railed on 'motion detected'. So I took a shot and switched the black and the red leads (working off the 5V Arduino USB power). Still no change in response with motion/No motion. Replaced the 10K resistor with a 1K and then it was always railed the other way - no 'motion detected'. Added a 10K pot to the 1K resistor and got it to work somewhere in between 10K and 1K. Don't forget to put the 1K in series with the POT to make sure you keep the current sinking into the signal lead from becoming a short. Turns out with the sensor I got, the signal pin is red, the +5V Power pin is black and the ground pin is brown!

  • joshsh / about 12 years ago * / 1

    Let me add another warning not to become a casualty of the datasheet. If you hook up the sensor backwards (red wire to input and black wire to +12V) - an easy error to make because the plastic connector in the image is in the "wrong" orientation -- it will not only fail to work properly... it will die with a little puff of black smoke and the smell of fried circuitry. $10 down the drain. Read the Bildr tutorial before attempting to hook up the sensor.

  • Member #331890 / about 12 years ago / 1

    If you want to create a top notch motion detection system, you can use two different sensors at once: this PIR sensor and an X-Band microwave motion sensor. In this way you will be able to reduce the false positives which can be caused by sunlight or by EMI.

  • mrglover / about 12 years ago / 1

    When will this product be back in stock?

  • baum / about 12 years ago / 1

    Why is this jumping? If I wave my hand in front of it, it goes low, then high, then low, then high, and keeps jumping around for about a second.

    p.s. I jumpered the regulator.

    • baum / about 12 years ago * / 1

      This sensor is really going to kill me. It goes constantly low when I plug a speaker in and call tone(). Unplug speaker, it goes high and starts working again!!!

      • Chilean / about 12 years ago / 1

        All of these symptoms are related to the power issue described in other posts above. Are you powering your setup via USB +5v?

        USB is not enough power. It will prevent the sensor from working correctly. Try using external power (+12v) and you will see how it works with the speaker.

        • baum / about 12 years ago / 1

          That can't be it b/c I was powering it from my ATX power supply...

  • baum / about 13 years ago / 1

    This is A Really Useful Sensor. But it is equally, if not more, complicated than it is useful. I would like to (try to) clear up some points about it:

    The datasheet lists the op. voltage as 12V. Sparkfun says 5-12V. Yet some people have trouble using it with their 5V arduinos.

    The smallish chip in the top left is a voltage regulator: a L78L05, to be exact, with a dropout of 1.7V. So by feeding the sensor 5V, it gets regulated to about 3.3V. BUT THIS IS NOT A 3.3V REGULATOR! To give the sensor itself 5V, you must feed it 6.7V.

    But now, a problem. The large chip is a BA10324AF, which is a quad op-amp. It has an operating voltage of 32V+/-16V. WTF?!? So the minimum voltage is supposedly 32-16=16V? But that doesn't make any sense... why would there be a 5V reg on board? Something here is messed up. Hanse Electronics (the sensor manufacturer) messed it up, I think.

    But this doesn't explain why some people get it to work off 5V, and others don't. Any ideas?

    My conclusion: This regulator can handle ~30V, so give it the highest voltage you can.

    • MikeGrusin / about 13 years ago / 1

      Many op-amps can be run on either a single-sided supply (positive voltage and ground), or a split supply (positive voltage and negative voltage). That spec states that the op amp can be run up to 32V on a single supply, or +16V / -16V on a split supply. In this case, it's running on a single-sided supply.

      As your research shows, you should run this sensor on at least 6.7V to ensure the 7805 works properly. I wouldn't run it on much more than 12V as you'll be heating the 7805 excessively and it may shut down. The reason some people may be getting them to work at 5V or below is that linear regulators may pass some voltage through them when the input is below the dropout voltage. It's a failure mode, and the voltage is certainly not regulated, but it may be enough to allow the circuit to work to some extent.

      • baum / about 13 years ago / 1

        But by bypassing the regulator, could I give it any voltage 0-32 volts? And why have a 5V regulator on board? Since this is an open-collector output, no change would be seen (on the output) if the sensor was run at 1V or 10V. Or is this a problem with the IR sensor?

        • MikeGrusin / about 13 years ago / 1

          I haven't traced the circuit, but designers don't add regulators unless there's a good reason (cents count in this business). The only thing I can say for sure is that if you bypass the regulator, you can run it off 5.0V. Anything else and you're asking for erratic operation or smoke.

          • baum / about 13 years ago / 1

            As for "bypassing:"

            Can I solder a wire from VIN to VOUT (and still use the connector's power pin), or should I just solder a wire to the VOUT pin and use that?

            • MikeGrusin / about 13 years ago / 1

              I'd either solder a new wire to the regulator's output, or remove the regulator entirely and bridge the input pad to the output pad. Otherwise the regulator will still be trying to regulate and fight against the voltage at its output.

              • nhunsperger / about 13 years ago / 1

                While removing the regulator would be the cleanest, simply bypassing it is fine. An LM7805 can only source current. If it thinks the output is too low, it internally connects the input to the output. If it thinks the output is too high, it internally disconnects the output from the input. In either case, it will never try to sink current to reduce the output voltage, which is why a simple wire bypass is fine.

  • baum / about 13 years ago * / 1

    Male headers don't fit. And wire is slightly too small. The best bet would probably be to cut off the connector and put on your own wires.

    edit: female headers (like the ones on an arduino) fit PERFECTLY!!!! So put in a 3x1 female header, and put wires into them.

  • baum / about 13 years ago * / 1

    To the manufacturer (and any other confused consumers):

    Black is supposed to be ground. Not Signal. Brown should be signal. But it's not. On this sensor, its ground.



  • Member #57306 / about 13 years ago / 1

    For a complete Arduino based burglar/ fire alarm system which could respond to this sensor, see...
    Note that it has the necessary "Wait for sensors to stabilize" code, among other things.

    • I have experienced the same issues as others; using the 5V pin on the Arduino Uno does not work. However, I did get the SE-10 to work correctly when I used the Vin pin instead (with the USB power). Of course the question now is why does Vin work and the voltage bounce all over the place with the 5V pin. Has anybody been able to get this to work reliably on the 5V pin?

  • Nidhal / about 13 years ago / 1

    Very accurate when used with 12V. Don't even the arduino 5V pin, it won't work.

    • Abalam / about 13 years ago / 1

      Exactly the same behavior here.
      I've a 3v3 Arm processor, i purchased this sensor because of specifications notice "if you bypass the regulator, it can work with 3v3"..
      Unfortunately, i tried to bypass and use the 3v3 arduino power to test it and it's always flapping.
      I tried with the 5v through the sensor's regulator and it's flapping too...
      I tried with a 9v battery, and it becomes quite accurate (the multimeter show the LOW state when i move my hand in front of the sensor).
      I don't have a 12v supply, but i'll think about it...
      I checked the voltage on the regulator and it's really always 3v3, why can't it work with a direct 3v3 behind the regulator ? And why does it work when the regulator supply 3v3 from 9v, and not 5v ?

  • jtoledoc / about 13 years ago / 1

    Is there any enclosure for them ?

  • sbright33 / about 13 years ago / 1

    It works great for me! BUT I had to use the pull up resistor AND bypass the 3.3v regulator. Only then did it work. The internal Uno pull up is not enough. Using 5v I measured 3.7v on the other side of the regulator. The output never settled until I bypassed it. Now it's wonderful!

  • LongShotBuddy / about 13 years ago / 1

    What is the connector on the cable called? Do you have it's mate?

    • baum / about 13 years ago / 1

      Cut it off, strip the wires, and solder on your own wires.

  • R0B0T1CS / about 13 years ago / 1

    You can contact manufacturer Hanse Electronics Co., Ltd. http://hanseelec.co.kr/eng/
    Anybody know the field of view angle?

  • Member #116618 / about 13 years ago / 1

    how much meters does the sensor works ?

  • ThePICMan / about 13 years ago / 1

    Has anyone tried putting this to "sleep" and cycling on periodically to save on battery power? Doesn't seem like it would lend itself to this very well...

  • jma89 / about 13 years ago / 1

    So, I don't mean to draw business away from SparkFun at all, but I was at RadioShack yesterday and picked up a motion detector that (at first) I thought was just like this one. (Same price too: $9.99)
    Turns out their model (A Parallex Passive Infrared Motion Sensor #555-28027) is a bit easier to work with: Provides three 0.1" spaced pins that work on the corner of a breadboard, and it simply pulls the signal pin high when it sees motion. (I hooked it up via a transistor to an LED [Just to be safe and not kill anything] and it works great.) It even has a jumper to set the sensitivity/distance that it "watches".
    Although I will say: It appears to be a tad more reliable on the low distance (15 feet) setting as opposed to the 30 feet setting. (That or it doesn't like a hand passing right above it when it's "looking" 30 feet out; I've barely played with it enough to tell for sure.)

  • Member #202638 / about 13 years ago / 1

    Hey, I'm very new to electronics, but basically I'm trying to trigger a 3/4" Irrigation Vallve with a solenoid, would this work well?

    • Member #190411 / about 13 years ago / 1

      i've done exactly that with this sensor. iirc it only pulls the line low for a second or two though so i set it up with an atmega48 to poll the sensor and turn on the solenoid for 10-15 seconds, and also limit the number of cycles so it can't get stuck on if the sensor fails etc.
      a neighbors cat was digging in my aunts garden and apparently it doesn't understand english, but it understands getting blasted with water quite well :)

  • straylight / about 13 years ago / 1

    could you guys carry a sensor that operates off 5v instead of 12v? I bought mine else where but would buy from you guys instead if you carried them.

    • baum / about 13 years ago / 1

      It is supposed to work @ 5V... not as well as @ 12V, but it does work.

  • knuckles904 / about 13 years ago / 1

    Can anyone confirm this works (well) at 3.3v? Range any worse?

    • SomeGuy123 / about 13 years ago * / 1

      Just jump the regulator.
      Take a look at the picture that shows the back of the board. The chip in the top left corner is the regulator.

      • baum / about 12 years ago / 1

        I did that, works nicely @ 5V. Should work at just about any voltage, as the large chip on there is an op-amp w/out any real minimum voltage restriction. so 3.3V should work once jumped.

      So naturally, it won't work. Minimum voltage = 6V.

  • I have a question.....When sensor detects something or something moves (according to overview and datasheet), the "alarm" pin will go low. But. Does anybody knows what appened after that?, I mean, the "alarm" pin still in LOW? or will go HIGH inmediately (when nobody activated it). How much time the "alarm" pin is Activated (when somebody pass in front of the sensor)?
    Thanks for ideas!

    • I think the alarm pin will only stay low until whatever is moving stops moving. Then it'll go sprOING! back to high.

  • JohnDimo / about 14 years ago / 1

    Is there an Eagle library available for this part?

  • Jabel / about 14 years ago / 1

    Hey y'all. Does anybody know much current this thing draws in an idle state? I'd like to know how long it would last on a standard 9V battery.

  • Mitch5 / about 14 years ago / 1

    I'm not sure why all the Arduino examples with this sensor show the alarm pin attached to an analog pin on the Arduino. I hooked mine up to a digital pin and did a digitalWrite(ALARM_PIN,HIGH) to turn on the internal pull-up resistor and it works great!

  • Jorge-EE / about 14 years ago / 1

    Here is a simple schematic i made up. I used the 5V source off of my mbed microcontroller.

  • Maxtor / about 14 years ago / 1

    Muy facil de usar, buena sensibilidad, buen rango de deteccion (recomendable para techo)... simplemente conectas y puede ser acoplado directamente a un NE555 para controlar iluminacion por presencia!!!

    • Member #116618 / about 13 years ago / 1

      Hola, me podrias asesorar. Tengo la siguiente duda : Cual es el rango de deteccion en metro ??

  • brunner / about 14 years ago / 1

    I just got this the other day, and hooked it up to a Duemilanove. I have 12v at the power connector, ground at the ground, and a 10k pullup resistor to 5v. I get a constant low signal when I try to read the signal digitally, but reading it with analog gives a reading of around 430 (a bit under 2.5v) when it should be detecting something, and around 250 (around 1.25v) when it shouldn't. Does anyone know what I might be doing wrong? I stripped it down to have nothing but the Arduino and the PIR on the circuit, and reported the results with a serial line to my computer.

    • One dude said that they tried a 1K resistor. Try that.
      EDIT: and maybe it's detecting little bits of motion.

  • Matt3 / about 14 years ago / 1

    Has anyone tried these out against the new 'ePIR' modules from Sparkfun? The ePIRs cost a little bit more and claim to have a higher sensitivity.

  • mikitnt / about 15 years ago / 1

    I have just bought an PIR Motion Sensor but I am not sure that it works.
    It has tree pins as the image says, I put 12 v in the red pin, put the middle to ground and it is supossed I have to get a voltage in the alarm pin.
    I close the circuit with a resistor in the alarm pin and then the resistor to ground but when I measure voltage in the last pin or in the resitor 0 V is obtained, also covering the sensor.
    is the motion sensor broken?
    could anybody help me? Thank you in advance.

    • Jerome Moreau / about 15 years ago / 1

      Hi Mikitnt,
      This is normal : you're supposed to use a "pull-up" resistor, meaning that it should be connected to the positive +5v and not to the ground as you did.
      When the alarm is OFF, the sensor's Alarm pin will behave as an open circuit (i.e it will behave as if it's not there) and so your microcontroller analog input pin will end up connected to +5v through the resistor. If you read the analog value of your analog pin at that time, it will probably show up as 1023 if you've got a 10bit analog-to-digital sampler for instance.
      When the alarm goes ON, the sensor will "pull the pin to the ground", meaning that inside itself it will connect the alarm pin to the ground. This is where the resistor part comes in : current will always flow through the path of least resistance, so instead of going to the +5v as before (because the resistor is in the way), the microcontroller pin also ends up being connected to the ground.
      On your analog-to-digital conversion, you will then see a low value and you can test against that in your code to make the alarm ring (or something).

  • zouze / about 15 years ago / 1

    i bought 2 pcs of these bt it does not work, what should be the value of the pull-up resistor?

  • DarronF / about 15 years ago / 1

    Works quite well, but running it at 5V is dodgy - probably because the +V is run through a 5V regulator, dropping the actual voltage to a less stable lower value. Works great at 9V, or you can bypass the tiny regulator and drive the 5V directly.

  • Phoenix123 / about 15 years ago / 1

    This says you can use it down to 5V but it does not appear to be stable to me at this voltage. The output is bouncing all over the place. When I change the input to 12V it works perfectly.

  • Hontat / about 15 years ago / 1

    Does anyone know how to adjust the debounce time for this?

  • cloverstreet / about 16 years ago / 1

    How far does this detect? I assume there is a way to reset it remotely?

Customer Reviews

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It's sensitive,, too sensitive.

The PIR sensor and all systems around it work great, fast and steady, though that last part does require the input voltage to be higher than 5 volts. That is, I tried to use the system with my arduino powering it with 5v, but I found the system to be too sensitive for small voltage variations, such as when my arduino would turn on an LED. Even when powered by its own source (5v, grounds interconnected) it was still looping in its own cycle of variation of input voltage, activating an LED, which caused an variation of input voltage. Even with a 3300uF capacitor the voltage couldn't remain stable enough for the sensor not to be affected. HOWEVER, after hooking the sensor up to its own 12v source, grounds interconnected, (as the manual says you should) the sensor woks perfect! It reacts fast, little bounce, and at a proper distance it has quite the FOV. I especially like that it doesn't have a build in timer, making the output as raw as possible, and yet translated to a simple on/off ground. Again, I found that it requires its own power source higher than 5v for true stability, but beyond that this little thing is well worth it.