Infrared motion detector circuit

Description.

Here is the circuit diagram of an infrared motion detector that can be used to sense intrusions. Infra red rays reflected from a static object will be in one phase, and the rays reflected from a moving object will  be in another phase. The circuit uses this principle to sense the motion.

The IC1 (NE 555)  is wired as an astable multivibrator. The IR diode connected at the output of this IC produces infrared beams of frequency 5Khz. These beams are picked by the infrared sensor, photo transistor Q1. At normal condition, that is, when there is no intrusion the output pin (7) of IC2 will be low. When there is an intrusion the phase of the reflected waveforms has a difference in phase and this phase difference will be picked by the IC2. Now the pin 7 of the IC 2 goes high to indicate the intrusion. An LED or a buzzer can be connected at the output of the IC to indicate the intrusion.

Circuit diagram with Parts list.

ir-motion-detector-circuit
Notes.

  • Comparators IC2a and IC2b are belonging to the same IC2  (LM1458). So the power supply is shown connected only once. No problem.
  • When there is disturbance in the air or vehicles passing nearby, the IR motion sensor circuit may get false triggered.
  • POT R5 can be used for sensitivity adjustment.
Show Comments

251 thoughts on “Infrared motion detector circuit

  1. ramon grande

    Hi, I want to build this circuit, for a “People detecting LED Mirror” But I got a few questions…

    1) Will it work for this project? LED and Phototransistor should be in the same place, side to side… or is this project intended to be a LIGHT BARRIER??

    2) R1 POT Should be set so that a frequency of 5KHz is obtained at the output (IR LED)???

    3)Is the first opamp array a band pass filter?

    Thanks a lot for your time, best regards.

    Reply
    • Seetharaman

      Hi Switch off lights when no motion is sensed. Put your imagination into work and get more ideas.

      Reply
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  3. Jadhav Pradeep Dinkar

    Sir, I want to make street light glows on vehicle movement. So for that I require circuit diagram mentioned with values of all component. So help me as possible

    Reply
  4. Prashanth P

    I want to get daily alerts to my mail about such circuits may I know if this is possible and if so can I get alerts

    Reply
  5. sanket

    hae plz give me proper circuit diagram working and all the details of project on rfid based path detection for blind person using 8051 microcontroller ….its urgent

    Reply
  6. alan

    looks awesome. I came across a networked motion sensor in proteussensor.com, and wanted to do something like that. this is really cool.

    Reply
  7. Vernon

    What can I use to replace l14f? Because it is not available in our place. And what is the model of the IR diode.

    And i have some problem in the transmitter. The 555 IC is overheating and then will burn. I don’t know why.

    Reply
  8. nikhil suthar

    sir,
    if there portion of what we need in the project and how to build then its batter for all
    if you can send me the datils of thease project motion detector please send me
    i’ll never forget your help
    thanku sir..

    Reply
  9. Amon.b

    hi sir
    Am doing the above circuit as my exam project,now am having chalenges finding the capacitors.is there anyway i can modify the circuit?i will be grad to hear from you.

    Reply
  10. Prateek Chopra

    Kindly mail me correct circuit diagram for d above mentioned ir motion detector . As I have to make dis in my project plzz asap do d needful :) also send me d working principle , max distance btw transmitter and receiver .
    My email id is prateekchopra.101193@gmail

    Reply
    • akunne obinna

      hi vinod, you can check the convertion in nano farad and pico farad on the internet and see if it functions or better still, check another circuit in another site, there are so many like this around with different values, but the same functions.

      Reply
  11. vinod

    Hi,am doing a project,named infrared motion detector.i want to know the distance between transmitter and receiver…just reply for me

    Reply
  12. syed.s

    hello sir. i need one circuit for automatic FAN on/off.IF anybody near the fan (2 feet distance)its automatically switch on.If there is no person in front of the fan will stop after 30 seconds automaticaly.Pls send me the Circuit Diagram my mail ID : ss_baboo@yahoo.co.in.Sir I am awaiting your Reply pls.Thnks

    Reply
  13. jimmy

    may i know instead of using transistor L14F,what component can be used in simulation?what component can be used to replace this component because i cant find this component anywhere?
    please help..urgent..TQ.

    Reply
  14. uche michaels

    Can u explain to me? Why is it that when you walks into the field of view of the PIR sensor and stands their the piezo alarm stops ringing.help

    Reply
    • Greg

      This is a motion sensor. It works by detecting a phase difference in the reflected light that hits the phototransistor, which will only happen if an object moves in front of the path of the infrared. This won’t happen if an object stays still.

      Reply
      • dileepa mahaegodage

        no Greg, its not. the device isn’t designed to identify any phase differences. it just simply detects the reflection of the i.r beam transmitted by the emitter diode.and this is not a motion sensor(even they say so). you can call this a proximity sensor. simply you could understand this by looking at the way which ic 2a is wired. non inverted pin is just grounded. No differential modes.and you need some direct link between the transmitter section and receiver end to detect the phase difference.its just amplifying the signal. read the diagram before commenting. otherwise you’ll ending up making yourself and few others fools.

        Reply
  15. patrick o

    pls i would need d secret on how to make this circuit work i also need d working principles of the circuit thanks everyone

    Reply
  16. tony

    The IR motion detector is not function after following all that is required from the circuit displayed. please help, thank you in advance.

    Reply
  17. Cgabriel

    i have a question reguarding the inductor used for reciever can i use a chock with the same 1uH value and would it work correctly. hask this becouse i cant fined and inductor at any of the local electronic stores.
    im building this project for my capstone project for my school can you help please.

    Reply
  18. alien

    Dear sir,
    I have made the transmitter and that is working fine but in receiver the volt remains constant around 10.95v.I supplied +12v,-12v and ground as need. and i also inverted the 5 and 6 pin of ic2b to get positve output at the receiver but the output is always remaining constant.please guide me how to make the receiver working

    Reply
  19. asher

    I liked the circuit and concept and m making this for my 4th semester project. I have a some questions….Is an infrared reflector(shiny surface) required at the other end for the the transmitted IR beam to be reflected back to the phototransistor or will any surface eg wall/wood suffice?, During intrusion the IR beam would reflect at another angle to receiver and the angles for intrusion and reflection from wall would be different…so how can i fix that….i mean i can’t open box and change positions each time for different distances of intruder and wall…? Secondly, how can i adjust the circuit such that instead of an alarm ringing during the short period of intrusion, the alarm rings until the circuit is manually reset after intrusion? For how long distance does the circuit work? Is there a different IR diode/phototransistor to be used for longer distance coverage? Thanks

    Reply
  20. Seetharaman

    Hi Ashnuka all capacitors used are non electrolytic you can use paper, polyester, ceramic etc. working voltage should be 16 volts or better.

    Reply
  21. ashnuka

    Can electrolytic capacitors can be replaced(by Ceramic,Mylar,etc.)?If the answer is no are there any replacements?these electrolytic capacitors are very hard to find in here.

    Reply
  22. Tess

    pls can anyone send me the working principle of this circuit and how the components function individually in the circuit,pls it kindda urgent. what exactly is the distance the receiver and transmitter be separated?

    Reply
  23. jessy

    Dear Panda I have sent u a mail requesting your help for this circuit…. please send me the working and the correct circuit diagram….. Thanking You :-)

    Reply
  24. jessy

    can anyone please tell me the entire working of the circuit…plz….
    very urgent…. thanks in advance….
    another doubt is between which pins the buzzer should be connecter???

    Reply
  25. virender

    Dear PANDA, I want to make 5VDC transformerless power supply from AC230 volt to run Remote Control Switch. I downloaded the circuit without transformer of five volt but it did not work. When I give supply from usb port of CPU it worked very well. Can you please let me know how to make 5VDC power supply without transformer. Please help in this regard, if possible. Any reply shall be highly appreciated. Thanks in advance!

    Reply
  26. PANDA

    Virender,

    Theoretica the circuit above works, this largely depends on your PCB or Vero Board design. You must triple check all your connections and make sure you have all ICs and Photo devices around the right way. As a tip I would mount the ICs in IC Sockets, this allows you to check voltages and polarity before you insert the ICs. While building this I actually damaged IC2 twice and had to replace them ! I will send you my document on how the circuit works.

    Reply
  27. virender

    Hello, Dear Panda. Thanks for yor kind reply. can you plz. send me the correct diagram of the the same by mail me to “vrndrsngh85@gmail.com”. If possible. With thanx.

    Reply
  28. PANDA

    Virender, I believe pins 2 and 3 are correct as shown but Pins 5 and 6 in above diagram should be the other way around !

    Either that or the data sheet for the photo transistor was wrong and I have the emitter and collector backwards. Anyway it worked OK when I re-did the connections (again)and swapped Pins 5 & 6 on IC2b.

    Reply
  29. PANDA

    Hello Shehryar, Yes I can explain in detail or very simply how this very basic Infrared Intrusion detector works. My email address is in one of my responses below. I can send you a text document describing it if you would like !

    Reply
  30. Shehryar

    I’m a beginner hobby electronics enthusiast whose interested in making this circuit. Since I have only rudimentary knowledge of electrical devices, can someone explain how each component in the circuit works and why is an RLC circuit attached to the OP-Amp IC2A? I’ll be grateful to anyone who can help.

    Reply
  31. virender

    Hi all, can any one let me How to change LM1458. As I could not find it in our area. The shopkeeper gave me its substitute of IC7458. Please let me know IC7458 can be used in place of LM1458. Any reply shall be highly appreciated. Please mail me to ” vrndrsngh85@gmail.com ” in this regard. With thx.

    Reply
  32. viredner

    Hi all, can any one let me How to change LM1458. As I could not find it in our area. The shopkeeper gave me its substitute of IC7458. Please let me know IC7458 can be used in place of LM1458. Any reply shall be highly appreciated. Please mail me to ” vrndrsngh85@gmail.com ” in this regard. With thx.

    Reply
  33. Pander

    Hello Vishal, Yes you can leave out C3 and L1 or keep them, either way it will work, I know this because this is exactly what I did after I got it working. Didn’t seem to make much difference and I was in a well lit flourescent dining room. No vehicles going past the dining table though so cannot vouch for that condition described in the text!

    Reply
  34. Pander

    This circuit works fine with a couple of changes:Set R1 on the transmitter to 25K Ohms, this will set the 555 to run at 5KHz. Use a digital camera to see if the Transmitter LED is operating! You do not need a Darlington Pair Receiver, just use a 940nm NPN Phototransistor ( Two Pin type)make sure you correctly identify Collector-emitter leads. Pins 5 and 6 on Receiver IC2b should be swapped, otherwise it will work opposite, that is, alarms with light and quite when dark !
    I used three 9V batteries, made a 9V split supply for the receiver. It does work !!!!

    Reply
  35. Akshay

    Hello i am making a project based on IR sensor…
    The problem is that if I am bringing any obstacle in front of the sensor that sensor is not making the port high it do not change why is it so? Thank you..

    Reply
  36. vishal panchal

    Can u please tell me how can v make inductor of 10uH shown in fig.
    Is it necessary to use inductor ? Can v make the circuit without using
    an inductor ?

    Please reply as soon as possible. Thank you.

    Reply
  37. Taofik

    Thanks Mr. Seetharaman. Can u pls suggest the type I can use for a streetlight control. Or probably what I can do to this circuit to cover more distance.

    Reply
  38. seetharaman

    Hi Tofman normally these sensors respond in a living room say 20 by 16 or so(in which i have tried beyond this i have no idea. If any body has the results please respond

    Reply
  39. Taofik

    Mr Dileepa mahaegodage. Pls i’ll be needing your help concerning my project. I’m working on an automatic streetlight that would be controlled by a motion detector.
    My email addy is; tofman2020@yahoo.com
    I’m not getting through to your email addy. Pls i’ll be waiting.

    Reply
  40. Taofik

    Pls what is the maximum distance betweeen the transmitter and the receiver? Iwant to know if this circuit will be useful for my project.

    Reply
  41. farrukh

    thank you for your circuit i was wondering if we could bring its functionality as a digital circuit. i mean interfacing it with an ADC and FPGA. is that possible if any one has an idea about it so please do tell me thank you my email address is
    farukhalvi1988@gmail.com

    Reply
  42. Noraa

    another question to clarify things, for the output, either LED or buzzer, do i need to connect it to pin 7 of IC2b and pin 1 of IC2a or pin 7 of IC2b and ground? which configuration is correct? thanks in advance.

    Reply
  43. Noraa

    hi guys, i’m using this circuit as my project.before i start doing it, i just want to ask is there anyone here who actually made this circuit and got it working? kindly email me the necessary modifications if there are any because as what i’ve read in the earlier comments, the receiver circuit is not working.

    aaronmichaeltolentino@gmail.com

    Reply
  44. A.Majeed

    Hi
    What is L14F? A phototransistor? Is there any alternate to it?

    And plz suggest how to maintain line of sight of the transmitter

    Reply
  45. Bernie

    Please help. 1. What is the IR Diode (D1) part number? 2. How is the IR Diode (D1) and sensor TR (Q1) positioned physically? Side by side aiming intruder direction? In this case,how far can it detect and what angle?

    Reply
  46. Mo

    I would advice anyone building this circuit to use another receiver. this one is too complicated. i took this circuit as an end of year project. wasted too much time fault finding. use another IR receiver circuit.

    Reply
  47. Seetharaman

    Hi Rohit Due my preoccupation I could not sit with my prototype. i will give waveform details etc soon.

    Reply
  48. kibett

    Am doing a project on an automatic car park system and so far am doing well.I have constructed the cct but i have a some questions to inquire from you before i proceed further

    1.Would you please give me a detailed explanation of how the receiver works ie from the photo diode to the IC2b pin 7.

    2.Can feed the signal obtained in pin 7 to an IC 8085 then to a 7 segment driver to convert the analog signal to digital which will be displayed on a 7 segment display.

    please i will be grateful

    Reply
  49. sujit

    hey laz i too have constructed the ckts but ma reciever aint working….if yu get the reciever to work kindly comment back….

    Reply
  50. laz

    i have constructed the circuits, the problem is that the LED IS TURNING ON AS SOON U POWER ON EVEN IF THERE IS NO PHOTO RECEIVER

    Reply
  51. sujit

    transmitter’s working fine….but reciever aint :( ….is there ny modification need to be done in the reciever ckt from above…

    Reply
  52. George

    Has anyone gotten this circuit to work. I have gotten the transmitter to work, it is outputting 5kHz at the ir led and 220 node. The reciever however is construced as above yet the output never changes when there is movment between the diode and phototransister.

    Reply
  53. Seetharaman

    Hi Sujit you should get between 30 to 300 kHz from pot one end to other. check your components and IC.

    Reply
  54. sujit

    hi seetharaman thanks for replyin……….i kinna went through the comments the one change that should be made is ” there is no load resistance for Q1. R4 should get shfted to emitter and collector should get connected to +12volt,”

    is this the only change to be made??????????

    Reply
  55. sujit

    hey all im thinking of doing this as ma course project……..does this circuit really work or are ther any flaws in this circuit?????????

    Reply
  56. George

    I am having problems getting this to work. The transmitter is working properly, I am getting a 5kHz square wave output, however the output voltage of the receiver stays at the 12 volts that is input. I am using an lm45558 ic in place of the lm1458 and only had an 8uH inductor instead of a 10uH. Any ideas on what could be going wrong. Also the ir diode and transistor came in a pair from radio shack.

    Reply
  57. Furqan

    Hi, m nill in this field.. i will get help from some experts to design this circuit, but one question that.. how is it going to alarm and where.. is it possible that if it detects motion and transmit waves to alarm receiver and start alarming.

    i want to make it for home security.

    Reply
  58. Gerald

    HI Seetharaman,

    Thank you for your advise!! I was thinking to use a 9VDC battery to suuply this project. I manage to step up to +12VDC but notable to get the -12VDC. Can you helptoadvise how to goabout it ? TQ

    Reply
  59. Seetharaman

    Hi Gerald you require plus12 minus 12 and 0 volt reference supply for this circuit to work. you can use any dual supply circuit appeared in this column and use a suitable transformer to get the required voltage.

    Reply
  60. chrisblcisgreatpvp

    You may find it easier to completley remove the negative feedback loop that contains the inductor, capacitor and potentiometer. Essentially creating two comparator circuits from the Lm1458.

    Sp pin 6 will be negative, and as long as pin 5 is under about 5v when your infra red phase difference changes your output at pin 7 will be high.

    If you really want an inductor buy one, it is much more simple and not hhorribly tedius using the formula for inductance that relies on coil length, turns and what not.

    You may be able to change the IR transmitter and sensor but i’m not sure about using a 741 op-amp.

    Reply
  61. LAZARO

    can anyone help me i’m doing this circuit as my project is it possible to replace IR DIODE with the transmitter diode on DVD remote and also to replace photo transistor with the receiving transistor on DVD.IS it possible to replace LM1458 with 741 opamp

    Reply
  62. Richb1504

    So i’ve been working on this circuit since late febuary, I’ve made the 555 and tested it with an oscilloscope and works at 5Khz great. The problem is the Inductor L1. I know how to make it but how important is it? Can the circuit work without it or is it necessary in distinguishing a change in infra red phase difference?

    Please reply with any info

    Kind Regards Rich.

    Reply
  63. aldrin

    thanks Seetharaman, i just have to find all the right parts and give it a go…thanks again and have a good day…

    Reply
  64. Seetharaman

    Hi Aldrin facing each other is the best position, but with reflected rays from the smooth wall also will do – towards the space monitored. (reliability depends on the reflecting surface).

    Reply
  65. aldrin

    hi seetharaman, thanks for replying…you stated “can be independent units”, does that mean they can be incorporated in one unit and still work?(only less effective??)…if they are in one circuit board, should the IR diode and transistor be facing each other or towards the room/space being monitored?…apologies for the newbie questions…thanks again for your help…

    Reply
  66. Seetharaman

    To cover more area of the room both can be independent units and positioned in such a way they respond to movement in the anywhere room.

    Reply
  67. aldrin

    hi all, are the 2 circuits supposed to be placed separately in the span of the space you want for detection (motion/interference between IR diode and transistor)? kindly help

    Reply
  68. yen

    hi~ it is in one strip board or in 2 strip board? and it need 2 12v supply or how? i’m not really understand on this circuit. can anyone help please? thx!! ^^

    Reply
  69. gelyn

    is the pairing of transmitter and receiver sensitve enough for detection?I used an alternative components but it doesn’t work..xD

    Reply
  70. Priscilla

    I have constructed this circuit, but I also have some problems on it. The circuit didn’t work with the RLC filter even I calculated the value of L C. Is there anyone can help me? Thanks.

    Reply
  71. Rakesh

    Hi,
    I’ve searched for the IC LM 1458, it is not available. Can anyone please suggest any substitute of LM 1458.

    One thing I want to suggest, If anyone not sure the IR transmitter diode not working, Just view it through your mobile’s camera , you’ll see it glowing in the camera if it’s working. Try it first with your TV Remote.

    Reply
  72. amit

    Hi SHUBAM…

    I also want same feature like what you posted…..
    please i have joined this blog site later…
    if u got information from any sources or if u already made it..then please help ..u can send mail:k.amit.tc@gmail.com…

    Thanks & Regards

    amit

    Reply
  73. amit

    Dear all ,

    Can anybody help me by informing that “is above circuit working or not”…making cost…feasibility and time ( days) to finish…
    please help or send useful information to my mail:k.amit.tc@gmail.com..9008788699…

    Even i want help from administration side too

    I shall be highly obliged for the same…

    Thanks & Regards

    amit

    Reply
  74. Seetharaman

    Hi RCRAGHU sorry it is left out R1 R2 junction should be shown as connected Pin No7.
    You can try Photo resistance (LDR)with RED or white LED for the transmitter. LDR cannot respond to IR rays. it can respond to only human visual spectral band.

    Reply
  75. samo

    ok this project is realy good
    but when an object detected shoold be a period of time before the output of ic2 go low i mean like tamprositor

    Reply
  76. SHUBAM

    As you know that infrared and photo transistors dont show or give any indication .. for that purpose(b/c its cant be seen from humen eyes) i have to put buzzer or any led or any thing , but the think is that i want to run my circuit as the infra red transmitted its rays and photo transistors recieve at the reciever end , actually i want to run my circuit when the connection b/w infrared and photo transistor break( mean some body walk out b/w the connection of ir and photodiode) then buzzer or led give some response .. so that we can called this circuit infra red motion dectector .. plz give me your response soon , i dont have much enohgt time …

    Reply
  77. seetharaman

    You are correct it detects only the change in signal level and not the phase, small quantum of phase detection is very difficult.

    Reply
  78. Electronic engineer

    It detects changes in the strength of the returned signal. Phase detection is much more difficult as the phase chang over a few metres would be very very small. cretin.

    Reply
  79. kt

    hi..i am doing this as my project..bt i think the connection L14F is incorrect…i guess this has to be connected in common collector mode right??
    also pls explain the detailed function of Lm1458 in the receiver side…is this circuit tested??

    Reply
  80. darren

    to ANA and AVI…i think d circuit is working,coz any moving object near the circuit,reflects ir rays and it will pick up by d rcvr side..try to leave the room a moment den observed d output..that is wen der is intrusioun/moving around/near the circuit,led is ON,its OFF wen nothing around..

    Reply
  81. darren

    can i used my old ir receiver from olt stock tv?also can i use lm339 as a voltage comaparator on d receiver stage??pls help me guys…tnx

    Reply
  82. Sam

    Hi.. Can anyone Please tell me the Series of (8-pin, 5-Bit) Infrared ENCODER and DECODER IC which should be easily available from market….
    I need a separate IC for Encoder and Decoder.. I’ve searched a lot but can’t find any…
    Please help me guys…

    Reply
  83. serafin castro

    this is a nice circuit for beginners and hobbyist alike i hope there will be a similar ckt for IR door or garage opener with the IR’s located on the same position,jst like the entrance opener on malls thank you

    Reply
  84. ramya

    I am one of the fans of circuitstoday.The circuits that has been displayed are really helpful for doing projects

    Reply
  85. Tomin

    Great circuit. I’ve been looking for such circuits for doing my collage project and I found some good circuits on Circuits today and CircuitSector…thank you very much

    Reply
  86. seetharaman

    Hi Anjum you please refer to my April 12 th feedback on load resistance for Q1. You can use any IR sensor available in the market for TV remote receiver. I am using that only. a 3 lead device with no marking on it costing around Rs20/-. As an alternate You may connect the emitter of the sensor to ground and take the signal from its colector and load resistane R4. this is what i have used for my IR remote control checker.
    I request ADM to reply AVI’s request.

    Reply
  87. Anjum

    SEETHARAMAN:There is the problem in reciever circuit . iam giving 10k potientionmeter to pin 2 of the reciever, but its giving same voltage at pin 7 has . why is so ? plz reply me as soon as possible , my transmiter is ready , but reciever has problem , pin 7 never go low or high its give me same voltage , as coming as from pin 2. plz solve this problem as son as possible . Iam in Hurry

    Reply
  88. seetharaman

    Hi Win you have use additional transistor(2N2219) because the IC cannot drive a relay directly since its maximum drive current is only 10mA.
    as the power supply for the circuit is 12volt, you can go in for a standard relays available in the market 12volt with a coil resistance of 100 to 120 ohms. (you can even connect a 12 volt electronic siren to 2N2219 collector directly, without the need for a relay)

    Reply
  89. win

    thanks seetharaman for your reply! so i need to connect a 2N2219 than connect to e relay? btw how many voltage relay do i need?

    Reply
  90. Anjum

    You are saying that if i interchange pin5 50k pot to pin 6. n in pin 6 work as the pin 5 is working . then when interuption is perform b/e ir reciever n photo transistor , then buzzer start its response .

    Reply
  91. seetharaman

    Hi Anjum you can use 9 volt battery for the transmitter without any modification, use only alkaline for longer life. Regarding your requirement, IR ray generated by the transmitter falls on IR sensor L14F, when the signal breaks the voltage at pin6 of IC2a will go positive and IC pin no7 will go low hence the relay will get de-enrgised. you can use normally closed contact of the reay for the purpose. if you want the relay to come on during ray interruption inter change IC2a pin 5 & 6. That will reverse the operation. Hope I am clear.

    Reply
  92. Anjum

    SEETHARAMAN: As you know that infrared and photo transistors dont show or give any indication .. for that purpose(b/c its cant be seen from humen eyes) i have to put buzzer or any led or any thing , but the think is that i want to run my circuit as the infra red transmitted its rays and photo transistors recieve at the reciever end , actually i want to run my circuit when the connection b/w infrared and photo transistor break( mean some body walk out b/w the connection of ir and photodiode) then buzzer or led give some response .. so that we can called this circuit infra red motion dectector .. plz give me your response soon , i dont have much enohgt time …

    Reply
  93. seetharaman

    Hi Anjum You need not connect +12volt to pin no7. you connect the base of 2N2219 to pin7 of the IC (if you feel a resistance is a must use a 100ohms between base and pin7 of the IC). and emitter to 0 volt. collector to relay and relay to +12 volt. whenever the in put signal is available to the receiver out put at pin7 of IC will go high (an active element in side the IC between Pin8 and Pin7 will conduct to give an output at pin7)that will make the trasistor to conduct and relay will come on.

    Reply
  94. Anjum

    SEETHARAMAN, Hi thanks for that, and i also want to use this 2N2219 buffer transistor with relay ,

    i also have to give +12 volt supply to pin 7, which give power to buffer n relay ?

    but when iam giving =12v to pin 8 n -12 volt to pin 4,

    Is this necessary to give power to buffer n relay separately ?

    Reply
  95. seetharaman

    Hi Anjum 100K pot is for gain of the receiver. 50K pot is for threshold setting (once the input -ve voltage to pin 6 exceeds the -ve voltge value set at pin5 by pot 50K) the out put at pin7 will go high.
    Hi Win you can use a buffer transistor say 2N2219 (as the IC output cannot drive a relay directly), connect a relay to its collector and +12volt supply rail. Do not forget the freewheeling diode for the relay.

    Reply
  96. Anjum

    Hi iam also working for this cct as my project , but i dont understand that how 50k n 100k potentiometer work , why we r using it ? i dont understand , somebody help me ?

    Reply
  97. avi

    L14G phototransistor will work in the circuit? L14F1/L14F2which will work?
    L14F is available in kolkata?
    plz give me information.

    Reply
  98. seetharaman

    Hi I have not yet tried this circuit, there is no load resistance for Q1. R4 should get shfted to emitter and collector should get connected to +12volt, i dont see any other problem.

    Reply
  99. avi

    I’m doing this for my final project. My due date is very near and I have a problem with the receiver circuit. The LED lights up as soon as the power supply is on. I couldn’t find the phototransistor L14F but I was told another one would work the same.is there any wrong with receiver circuit?

    plz help. urgent.

    Reply
  100. avi

    Is there any wrong in receiver circut?
    when i am applying power supply then led turn on.
    L14G phototransistor will work in the circuit?
    is L14F available?
    plz help……as soon as possible.urgent.

    Reply
  101. sampath

    “”””TO ANA””””””-i think the problem is when u power on the circuit it create signal in pin7.because this circuit work is based on two conditions,it’s like a OR GATE,when ic2a get a relevant frequency it’s works and prevent the signals to ic2b,if ic2a didn’t get the correct signal ic2b get a signal and amplifier it.so when u power on mean the the ic2a get relevant condition,i think if u focus the ir beam to photo transister it works properly.bye

    Reply
  102. JOSEPH

    GOOD AFTERNOON
    THANKS FOR THIS GREAT CIRCUIT, ITS BEEN REALLY HELPFUL. I JUST HAVE A FEW QUESTIONS. IS IT A MUST I USE THE LM1458? IS IT COMPULSORY I USE A PHOTO TRANSISTOR, CUZ, I BOUGHT AN IR DIODE AND RECEIVER. HOW IMPORTANT IS THE INDUCTOR? PLEASE CAN U GIVE ME A FORMULA SO I CAN MAKE IT MYSELF, I CAN’T FIND IT ANYWHERE. AND I NEED TO KNOW THE OUTPUT VOLTAGE, IS IT HIGH ENOUGH FOR A MOTOR?
    THANKS FOR YOUR ATTENTION!!

    Reply
  103. ana

    hi Admin,
    i’m doing this for my project (just like the others)… my problem is that once i turn the power on (i did the schematic you gave for a dual power supply circuit) the LED lights up immediately… what might be the problem… please help… my project is due a week from now… THANKS… in advance…

    Reply
  104. tracie

    Do I have to construct that separate circuit for the power supply? I have DC power supply source at +12V and -12V, I am just not sure of how to connect it to the circuit. My due date for project is really near. The transmitter circuit is working but the receiver side does not. when I on the power supply and start to tune R5 and R7 to ring, it will keep ringing regardless of whether IR is emitted to the diode or not.

    This is my first time constructing a circuit and I do have alot of things which I have not learnt to construct in college. Please enlighten me on this.
    Thankyou so much.

    Reply
  105. tracie

    Hi Admin,
    I’m doing this for my project and my due date is near. I’m facing a problem fixing the power supply. This is my first time facing a -ve voltage supply. Please enlighten me on how to connect it as my current way – by bringing two 12V supplies to parallel does not seem to work. Would I need a voltage regulator for this circuit?

    Reply
  106. srikanth

    what is the range of the transmitter? please can u tell me the formula for sensitivity ? if it possible to increase the range ? it can be applicable for hot body objects which emits IR rays ?

    Reply
  107. sagar

    help! circuit is not working properly? and base of NPN is open (not conneted any circuit pin )and does it works or not??? i’ve made all connetctions, and i’ve used LED instad of buzzer , LED are countyneously glowing. what i’m suppose to do now tomorrow is my presention day on 22 feb 2010.

    Reply
  108. tracshia

    Hi Admin,
    I’m doing this for my final project and have been trying to work it since weeks ago. My due date is very near and I have a problem with the receiver circuit. The LED lights up as soon as the power supply is on. I couldn’t find the phototransistor L14F but I was told another one would work the same. Please help me on this.

    I hope it’s okay to contact you via email. Or if not, I will be looking forward to your reply here. Thankyou so much!

    Reply
  109. twits4twats

    ADMIN

    Keep up the tutorials – I think you have a very good approach.

    Any way the website can be updated so that I can receive email for response to postings?

    Reply
  110. twits4twats

    can we use transistors in place of IC2 to drive a 8 ohm, 1W speaker??

    Carrion

    Presumming by your question, you wish to scare off creatures of some sort once they have activated the sensor. I would still use the op amp to drive the amplifier after all, that is what the op amp was designed for.
    Submit some details of what you want to achieve.

    Reply
  111. twits4twats

    can i connect camera in the output pin 7?? im doing my project in my local university with the same title as above. and my suggestion is to connect camera and the picture wuill send to the mobile phone.. anyone got any suggestion on how to do it?

    Jana

    Pin 7 is not for an output of IC1.It is for the timing of the 555.
    The fun in electronics is that you can achieve almost anything with a simple circuit.
    Yes you can attach a camera to this circuit however more details would be required of what you are trying to achieve so the circuit can be modified.
    Submit details!!!

    Reply
  112. twits4twats

    Hi Twits4Twats
    The reason I wanted to make the circuit was for a holiday in Kenya the idea being to leave it set up to fire a camera at night for any small nocturnal creatures that may have been passing. As it was the grounds were so well manicured that only the odd rat or squirrel would have come past i’m sure. Got loads of other wildlife though !!!!!!!!!!!!
    I’ve just noticed that pin 7 is not marked on IC1 in the diagram but a connection appears to be going to nothing. I assume they are one and the same
    Cheers

    jeffers

    Hi Jeffers

    Sorry dude for not responding sooner! I just don’t have time (wife and 2 kids…lol).
    Pin 7 – I just look at the schematic and naturally assume the pin locations. You are 100% absolutley correct. Pin 7 isn’t labled and should be the one that isn’t labled. ***ADMIN- PLEASE NOTE***. IC1 forms an Astable 555 timer circuit and pin 7 is typically the one you identified.
    You are correct about the Infra Red sensitivity. At best you are talking a few inches. This circuit is meant for close proximity however if you could upgrade the transmitting LED you could have a very good movement detector. If you Google around a bit I have seen versions for around 50m.

    Reply
  113. jana

    can i connect camera in the output pin 7?? im doing my project in my local university with the same title as above. and my suggestion is to connect camera and the picture wuill send to the mobile phone.. anyone got any suggestion on how to do it?

    Reply
  114. Jeffers

    Hi Twits4Twats
    The reason I wanted to make the circuit was for a holiday in Kenya the idea being to leave it set up to fire a camera at night for any small nocturnal creatures that may have been passing. As it was the grounds were so well manicured that only the odd rat or squirrel would have come past i’m sure. Got loads of other wildlife though !!!!!!!!!!!!
    I’ve just noticed that pin 7 is not marked on IC1 in the diagram but a connection appears to be going to nothing. I assume they are one and the same
    Cheers

    jeffers

    Reply
  115. Hassan Noman

    Thanks for this great circuit!

    @admin

    Can u kindly give me the circuit’s computer simulation file. actually I am making this circuit as my 4th semster OP AMP project.

    I need ur help.

    Thanks.

    Reply
  116. Ahpyinserrr

    Hi every masters,

    I’m just little boy,i would like make many rays of IR beams something like safety curtain its about 16 or 32 rays .So how can i parallel of all that IR rays..? OR Am i need to make of 16 circuit for 16 IR rays …?
    And i wanna know the distance between transmitter and receiver . Actually i want the distance is almost about 3 to 5 meter, can be possible to using this circuit..?

    Please explain to me as soon as possible …., THANKS TO ALL OF MASTERS. ;-)

    Reply
  117. Andrew Kent

    I am doing a project at my local college and was hoping to get the components list of this circuit. Also if possible what would be the best method of linking it to another circuit?

    Reply
  118. resty

    what will be the orientation or placement of the ir diode and photo transistor?
    do i need to place it face to face with each other.
    how will the ir diode work when somebody pass by on the ir diode?

    Reply
  119. twits4twats

    Thanks Twits4Twats
    To recap then if I put a buzzer or LED across ground and pin7 on IC2b. Set R1 and R5 to mid range and then adjust R7 at some point the buzzer should start to buzz if something moves in front of it. also if it have a split supply 12-0–12 then I need a voltage drop of 24 volts total ie a 24 V battery supply split from 12V+ to 12V –

    Hi Jeffers

    Sorry for not responding sooner. I haven’t built this circuit so please don’t quote me for accuracy but I can’t see why it won’t work.
    To answer your first question. Lets get this straight – ground is zero volts and not the -12Volts that IC2b uses. So if you were to conect a 12V buzzer from pin 7 of IC2b to pin 1 of IC1 or pin 3 of IC2a, then you should get some noise at some stage like you say. A point to note though, if you don’t get sound at all and you have observed the voltages correctly,is your buzzer self driving or does it need to be driven. Piezo buzzers work on an oscillating frequency. This means that the polarity of their voltage supply needs to be reversed at a certain frequency to get sound from it. If it is self driven, then it has a small circuit built in to do this polarity reversal. If it is not self driven, you have to then provide it with a circuit to do this polarity revesal.
    If you were to use an LED instead of a buzzer, as long as you connected it to the same points as above, you will be allright. You would have to add a 1K resistor in series with the LED though or it will burn out. General rule of thumb is 1K for 12V.
    Your second question. Yes, you could use a 24V supply to generate your +12V and -12V. See the link below.
    http://www.headwize.com/projects/cmoy2_prj.htm
    The supply can be anything. A battery or a PSU.
    As a matter of interest, why do you want to build this circuit?

    Reply
  120. david kibathi

    infra red transmitter is ok,but receiver output is giving me a constant voltage of +12v,whats the problem?

    Reply
  121. Jeffers

    Thanks Twits4Twats
    To recap then if I put a buzzer or LED across ground and pin7 on IC2b. Set R1 and R5 to mid range and then adjust R7 at some point the buzzer should start to buzz if something moves in front of it. also if it have a split supply 12-0–12 then I need a voltage drop of 24 volts total ie a 24 V battery supply split from 12V+ to 12V –

    Cheers

    Jeff

    Reply
  122. twits4twats

    Jeffers says:
    June 18th, 2009 at 7:49 am

    Thanks Twits4Twats

    Now understand that I need a split supply 12v+-0-12v- to the reciever. Are the 50K pots R1 and R7 used to match the pulses of the IR emitter and the photo transistor

    In laymans terms, R1 (in conjunction with C1) sets the RC time constant on the 555 which in turn sets the 555 pin 3 output to how long it switches the Infra Red LED on for. In this circuit it is calculated to be 5KHz. Simply put, you can use R1 to alter the frequency of the IR LED.
    R7 is used to set the value of the non inverting input (pin 5)of IC2b. Simply put, when pin 6 of IC2b then mathes pin 5, the output of pin 7 will go high.
    To answer your question, allthough not entirely correct, R7 is used to match the pulses of the emiiter and receiver.

    Reply
  123. twits4twats

    Steve says:
    June 24th, 2009 at 11:28 pm

    Excuse the newby question but what is the difference between -12v and ground.

    If you appreciate that ground is zero volts and +12V is therfore 12v higher than ground. -12V is then 12V lower than ground. Bascally, for some op amps to work a split rail supply is required (+12V and -12V).This can sometimes be bypassed by using an op amp that works off a single supply rail.
    Allthough the circuit above requires a single rail supply for the 555, it does require a split rail supply for the op amp.
    Try to google split rail supplies.

    Reply
  124. Jeffers

    Thanks Twits4Twats

    Now understand that I need a split supply 12v+-0-12v- to the reciever. Are the 50K pots R1 and R7 used to match the pulses of the IR emitter and the photo transistor

    Reply
  125. twits4twats

    To Jeffers
    By connecting pin4 to ground, the opamp will still work but not correctly.

    R5 is to do with negative feedback for the op amp. It adjusts the amount of gain for the op amp.
    Looking at the datasheets, I would say that yes the LM393N and the LM1458 are compatible, pin for pin.

    Reply
  126. Jeffers

    Oops

    In previous question I meant what does the 50k pot (R7) do.

    Does pin 4 on IC2b go to -ve pole of battery

    Reply
  127. Jeffers

    I Assume pin 4 on IC2b is to ground. what does the 50K pot (R5) do. I assume a LM393N will the same job as LM1458

    Reply
  128. Rashid

    Please some boby help me to find a circuit that change the voice/Sound pitch like girl to boy, like young man talking in old man sound pitch.
    can some body help me to find that

    Reply
  129. abhishek

    Where do you give the power supply to the transmitter ?
    how will the diode work without giving any power supply ?

    Reply
    • admin Post author

      oops! mistake from my part
      you can supply 9 to 12V to the transmitter circuit .
      i have corrected the circuit diagram

      Reply
  130. Robert

    I set up the circuit but for some reason the light I placed at the output (pin 7) stays on all the times. Do you have any suggestions of why this might be?

    Reply

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