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2 Simple Infrared (IR) Remote Control Circuits

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In this write up we discuss a couple of simple infrared remote control circuits designed for controlling any given electrical appliance through an ordinary or TV remote control unit.

Introduction

Controlling household electrical gadgets or any electrical equipment remotely can be fun. Controlling gadgets like a TV set or a DVD player through a remote may look pretty common to us and we are very used to with the experience, however for controlling many other domestic equipment like a water pump, lights etc we are compelled to walk around for implementing the switching.

The article is inspired by our usual TV remote concept and has been applied for controlling other house hold electrical appliances remotely. The circuit facilitates and helps the user to do the operations without moving an inch from his resting place.

The whole circuit of the proposed IR remote control may be understood by studying the following points:

Referring to the figure, we see that the entire layout consists of just a couple of stages viz: the IR sensor stage and the flip flop stage.



Thanks to the highly versatile, miniature IR sensor TSOP1738 which forms the heart of the circuit and directly coverts the received IR waves from the transmitter unit into the relevant logic pulses for feeding the fllip flop stage.

The sensor basically consists of just three leads viz: the input, the output and the biasing voltage input lead. The involvement of only three leads makes the unit very easy to configure into a practical circuit.

The sensor is specified for operating at 5 volts regulated voltage which makes the inclusion of the 7805 IC stage important. The 5 voltage supply also becomes useful for the flip flop IC 4017 and is appropriately supplied to the relevant stage.

When a IR signal becomes incident over the sensor lens, the inbuilt feature of the unit activates, triggering a sudden drop in its output voltage.

The PNP transistor T1 responds to the negative trigger pulse from the sensor and quickly pulls the positive potential at its emitter to the collector across the resistor R2.

The potential developed across R2 provides a positive logic high to the IC 4017 input pin #14. The IC instantly flips its output and changes it’s polarity.

The transistor T2 accepts the command and switches the relay according to the relevant input provided to its base.

The relay thus switches the connected load across its contacts alternately in response to the subsequent triggers received from the IR transmitter unit.

For the sake of convenience the user may use the existing TV remote control set unit as the transmitter for operating the above explained control circuit.

The referred sensor is well compatible with all normal TV or DVD remote control handset and thus can be appropriately switched through it.

The entire circuit is powered from an ordinary transformer/bridge network and the entire circuit may be housed inside a small plastic box with the relevant wires coming out of the box for the desired connections.

Circuit Diagram

simple infrared remote control circuit

The following parts will be required for making the above explained infra red remote control circuit:

  • R1, R3 = 100 ohms,
  • R2 = 100K,
  • R4 = 4K7,
  • R5 = 10K,
  • C2 = 47uF/25V
  • C1, C4= 22uF/25V,
  • C6 = 4.7uF/25V,
  • C3 = 0.1, CERAMIC,
  • C5 = 1000uF/25V,
  • T1 = BC557B
  • T2 = BC547B,
  • ALL DIODES ARE = 1N4007,
  • IR SENSOR = TSOP1738 image: Vishay
  • IC1 = 4017,
  • IC2 = 7805,
  • TRANSFORMER = 0-12V/500mA,

TSOP1738 pinout Details

Prototype image courtesy: Raj Mukherji

2) Precision Infrared (IR) Remote Circuit

The second IR remote control circuit discussed below uses a unique frequency and detects only the specified IR frequency from the given remote transmitter unit, making the design entirely failproof, accurate and reliable.

Ordinary IR Remote Drawback

Ordinary IR remote control circuits have one big drawback, they easily get disturbed by stray external frequencies, and thus produce spurious toggling of the load.

In one of previous posts I have discussed a simple IR remote control circuit which operates quite well, however the circuit is not completely immune to external electrical disturbance generations such as from appliance switching etc. which results in false operations of the circuit causing lot of annoyance to the user.

The circuit design included here efficiently overcomes this problem without incorporating complex circuit stages or microcontrollers.

Why LM567 is Used

The solution comes easily due to the inclusion of the versatile IC LM567. The IC is a precise tone decoder device which can be configured to detect only a specified band of frequency, known as passband frequency. Frequencies not falling within this range will have no effect on the detection procedures.

Thus the passband frequency of the IC may be set precisely at the frequency generated by the transmitter IR circuit.

Shown below are the Tx (transmitter) and the Rx (receiver) circuits which are set precisely to complement one another.

T1 ad T2 along with R1, R2 and C1 in the first Tx circuit forms a simple oscillator stage which oscillates with a frequency determined by the values of R1 and C1.

The IR LED1 is forced to oscillate at this frequency by T1 which results in the transmission of the required IR waves from LED1

As discussed above, R5 of IC2 in the Rx circuit is adjusted such that its passband frequency precisely matches with that of LED1 transmission output.

Circuit Operation

When the Tx IR waves are allowed to fall over Q3 which is an IR photo transistor, a subsequent order of varying positive pulses is applied to pin#3 of  IC, which is basically configured as a comparator.

The above function generates an amplified output at pin#6 of IC1 which in turn gets induced across the input or the sensing pin out of IC2.

IC2 instantly latches on to the accepted passband frequency, and toggles its output at pin#8 to a low logic level, triggering the connected relay, and the preceding load across the relay contacts.

However the load would stay energized only as long as  Tx stays switched ON, and would switch OFF the the moment S1 released.

In order to make the output load latch and toggle alternately, a flip flop circuit will need to be employed at pin#8 of IC2.

Parts List

  • R1 22K 1/4W Resistor
  • R2 1 Meg 1/4W Resistor
  • R3 1K 1/4W Resistor
  • R4, R5 100K 1/4W Resistor
  • R6 50K Pot
  • C1, C2 0.01uF 16V Ceramic Disk Capacitor
  • C3 100pF 16V Ceramic Disk Capacitor
  • C4 0.047uF 16V Ceramic Disk Capacitor
  • C5 0.1uF 16V Ceramic Disk Capacitor
  • C6 3.3uF 16V Electrolytic Capacitor
  • C7 1.5uF 16V Electrolytic Capacitor
  • Q1 2N2222 NPN Silicon or Transistor 2N3904
  • Q2 2N2907 PNP Silicon Transistor
  • Q3 NPN Phototransistor
  • D1 1N914 Silicon Diode
  • IC1 LM308 Op Amp
  • ICIC2 LM567 Tone Decoder
  • LED1 Infa-Red LED
  • RELAY 6 Volt Relay
  • S1 SPST Push Button Switch
  • B1 3 Volt Battery Two 1.5V batteries in series
  • MISC Board, Sockets For ICs, Knob For R6,
  • Battery Holder
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About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!



123 thoughts on “2 Simple Infrared (IR) Remote Control Circuits”

  1. Howdy, Friend! Interested to Learn Circuit Designing? Let's Start Discussing below!

  2. Hi Swagatam,

    I have successfully built this circuit and it is working perfect. thanks for that. I have an issue like others will have. the TSOP1738 is picking up any remote key pressed which is making not acceptable for any home appliances because In same room I use my TV, AC and many other remote controlled devices and this is picking up signals from any remote with any key press. Can you please suggest some additional circuit for it to only pickup the signals from specific key from remote. I am also good to make a transmitter for this too.

    • hello siddarth, your relay voltage must match the available supply voltage value, or you can use a supply source in accordance with your relay specs….but both must be approximately equal.

      however 5V can be used for operating a 6V relay, therefore you can use the 5V from the 7805 for supplying the relay also

  14. good day sir
    i have assembled the circuit. instead of relay i used a led from pin no 2
    i found the light is flickering continuously, when i press the remote i can see the light flikering more so i am concluding that the circuit detecting ir signals .but how to make it stable so that i wll be able to connect the relay
    i have did all the modifactions u mentioned in the above comments
    still its not getting stable
    thanking you
    john
    john

    • Good day John,

      did you try increasing the value of C6? increase it to 100uF and see the response. if still it's flickering then definitely there's some other fault in your circuit or may be the IC 4017 itself is faulty.

  20. Thank you sir your reply was helpful, what if i want to use both the 5v and mains supply? When there is power outrage and i might want to use the 5v battery so how do i go about it. And pls sir specify the kind of tv remote that would suit it.

    • for that you just have to connect the positive of the 5V battery with the output of the 7805 IC through a 1N4007 diode, cathode will connect with the 7805 output and the anode with the batt positive….the negative of the batt will connect with the negative line of the circuit

      all and any TV remote should work with this circuit

  22. Pls instead of using the rectificaton section can't i just use a 5v dc battery? And how do i connect it to the load?

    • you can use a battery, but battery will get discharged at some of time, that's why a mains operated power is recommended.

      the relay contacts and the load wires which are shown connected with the mains will need to be connected with the 5V supply

  24. Is there anybody who can provide a picture of their prototype ?

    The ones presented in this article are not quite what regular hobbyists would expect.

    Seriously, I do understand that this was created by someone with minimal experience, nevertheless any projects with parts floating in the air like that, should be advised that this is not a good practice.

    For the sake of everyone, a "cleaner" prototype would be appreciated.

    • Akula, I would suggest that you first learn the basics of electronics and regarding all the electronic components before building any circuit idea, otherwise you may find it extremely difficult and might not succeed.

  28. Hi sir i am an 9 class student i want to do a project which is to control lights with remote so plzz explain me the above in easy and in regular language so i can do it very ease plzzz sir

    • Akula, I have explained all the details in the article already, if you have specific questions you may ask them, I'll try to answer.

    • connect the relay coil with the transistor and positive….relay pole contact can be seen connected with the load, and either the N/O or the N/C contact may be selected and connected with one of the mains input, as indicated.

  32. Sir in the pic the ic2 is connected with a green wire.. Confused abt that and where does the green and blue wire leads to??

    • probably those are terminated out through a headphone jack for allowing the 5V to be accessible through the jack for some external DC circuit.

  34. Thnk u sir …sir where to put the leds….nd what to do with the earthing connection. ..should i leave the earthing or we have to earth them..

    • Aryan, you can put the LED in series with R4. The earth symbol represents the negative supply line of the circuit, make sure you connect all the marked points together with the negative supply line of the circuit

    • connect a red LED in series with the transistor base and first confirm whether or not this LED is responding ON/OFF with remote control button press…if not then there could be something severely wrong in the connections.

    • check voltage across T1 base and emitter by keeping the black prod of meter at base, and red prod at emitter, and simultaneously by pressing the remote handset button, it should change from 0 to 0.6V….if not check the same across the sensor output pin and supply pin….confirm this first

  42. Enter your comment… thank you for your Quick response ,its kinda working but there is still s problem its changes the state of the load just three times and would stop to work but when i unplug and replug its still repeat same three time and pause.pls help me. its urgent
    ojodarlinton@gmail.com

  44. its responding very slow. when i plug it the load comes on and when i press the remote button its goes off but when trying to put it on again it wouldn't until Upton 2mins before its responds.pls what should i do?

  46. In your circuit dia. the negative leg of C2 is connected to Vout of the IRS. Since C2 is a polarized cap., should it not be connected to ground instead?

  52. Hi, Can I use it to operate more than one relay at the same time by using other outputs in IC4017. Do I need to change the current rating of the transformer. Pls advise.

    • If you are interested to operate other relays in sequence one after the other by using the other outputs of the IC, then you can still continue to go with the same circuit because each relay would be operated individually and never together so there wouldn't be any increase in the current consumption during those operations

  54. Hello sir….
    I hv another question…

    In previous comments.. You said about TRANSFORMER that it stepdown 220v to 12v.

    If i put directly 12v adaptor… Then it work or not???

  56. Hello sir….
    You have a timer curcuit for mobile charger or etc..
    If i set the timing for 3 hour then after 3 hour curcuit stop the charging…. Or until curcuit will consume 3 hour electricity then it stop charging… Plz suggeste me this type of curcuit..

    Because overloading the battery will decrease life of battery.. So plz

    • Hello Saurabh, all cell phones have in-built sophisticated over charge cut off circuit so there's nothing to worry, the battery will never get overcharged even it's kept connected to the charger forever.

  60. Hello sir…
    1. What is the use of TRANSFORMER in this curcuit.

    2. Is this work on any T.V and setop box remote?? And which button is responsible for sending signals to receiver curcuit..

    • Hello saurabh,

      transformer is for stepping down the mains 220V to 12V.

      yes any standard IR remote handset should work with the circuit.

    • point and press the Tx at the sensor and see if it produces any changes in potential at the "out" pin, if it doesn't would mean the sensor is faulty.

  64. dear sir,
    it does not show 0v on DMM when ever i press button it shows 2.9v constant sir . I use the sensor which is used in our tv it don't have any number but i connect its terminals as TSOP1738 irs sir

    • disconnect the output of the sensor from R3 and then check, if still it continues to be the same you can assume the sensor to be faulty or wrongly connected.

      If it works correctly would indicate a wrongly connected T1 or a faulty T1

  66. dear sir,
    2.9v at sensor "out" terminal and 1v at the "Vs'' .It does not show 5v initially sir please tell what is the problem

    • please check the response with a IR transmitter, as explained in the pervious comment.

      you can connect an LED in series with R3 for getting indications regarding the switching.

      cathode of LED will go to R3, and anode to base of the transistor

    • point and press a TV remote control at the sensor, and check the voltage response at the output of the sensor..it must become zero or almost zero…. if not your sensor may be faulty or not connected correctly.

  72. dear sir,
    i connect the irs as shown in diagram but it is not working.sir please tell me the voltage or current across the components and is their any problem if relay inputs are change. how i check the relay whether it is working or not

    • Dear Ani,

      first make sure the sensor pinouts are connected correctly.
      Next, confirm the voltage across it's (+) and GND pins, should be 5V as per the circuit.

      Once you have confirmed the above take a DMM set at DC voltage range and connect its red prod to the "OUT" terminal of the sensor and black to the negative line of the circuit. Initially it should show 5V, but should respond with a zero volt or a lower voltage than 5V whenever the external IR remote is activated on it.
      Please first confirm the above.

  74. dear sir
    i connect circuit as shown in diagram but it will not working. sir ir sensor have a 2 terminals but in diagram it have 3 terminals. so i can not connect the irs to gnd and where i connect the remaining pins of ic 4017 please tell me sir

    • dear ani,

      you must use the one that's referred in the diagram.

      see the prototype images for getting the idea of the sensor type and appearance

  76. Hii sir is there any possibilities of using a transformerless circuit for this circuits power supply? I know its critical but I want to makes rhings more compact in a box thank you. 😀

  78. Sir, in the remote control circuit the feed is only 230Vac.What will be the relay rating?In this circuit there is no need of any external DC supply.Please help.

  80. Sir, in the design you have used a relay.What kind of relay is it?And what is the source of supply?

    • It's 12V, 400 ohms, SPDT, you can see it in the image below. the square orange colored block is the relay

  82. hi Swagatam ,
    i want to make "remote controlled switch board" through which i can operate 4-5 appliances bye remote control. so please suggest me circuit diagram with detail.

  84. Sir ,
    can i have circuit diagram for 'REMOTE CONTROLLED SWITCH BOARD' . through this i can operate 2 lights , 1 fan, 1 AC, 1 TV.

  86. Hi Swagatam,
    As Parthi Ban quoted the requirement of many loads, is it possible to use uC for the same? But for that we need to diagnose which button on Remote was pressed, can we detect that? (using the circuit you provided or any other).
    What's the difference between IR and RF wireless communications? (w.r.t. the current purpose).
    I definitely want to use uC, please suggest which one should i choose. say for controlling a minimum of 6 loads.
    Can you help in uC also?

    Anyways great job Dude !!

    • Hi Rahul,

      Thanks!
      A uC may not be needed for controlling more loads, it can be done by using separate receivers for each load and with a transmitter handset having individual buttons, just as we have in TV remotes.

      I would be addressing one such design soon in my blog.

  88. Sir, can you please suggest a circuit for the below mentioned purpose.
    "Current must flow in one direction and the amount must be controlled by a regulator (like in ceiling fans). And on moving the regulator in another direction the current must flow in another direction."

  94. hi sir…i am girish. i didn't get the phototransistor TSOP 1738, but in my area TSOP1838 is available .can i use that here…but i didn't get the pin configuration on internet…so can you help me???

  100. i have made this circuit. everything is well i tested, but tsop. the output still high even i press remote to it…. everytime i power it on. the relay active (connected to pin 2 of 4017). what wronge sir…please help..!

    • connect a 10k resistor between pin4 and pin15 and connect a 0.22uf or any close value cap across pin15 and positive…see if it helps.

    • i found the problem sir..when i test the circuit without tsop1738. it works well. so, i try to replace tsop1738 with tsop1138. it works well even under day light or cfl lamp. i use it to control the 220v 1500w chickent washing machine and work with only a cheap cell phone charger as power supply..it is very useful sir…thank much.

  114. ok Sir no problem if it's beyond your reach… then sir give me a detail explanation of IR remote control working so that I can explain it in my presentation…the questions that may be asked from this topic, brief me about them in document type link. thanks

    • I have already explained it elaborately in the above article, if you have specific questions you may ask them, I'll try to clarify them.

  116. Thank you so much Sir for your prompt reply 🙂 Sir,actually controlling light/fan/ac is somewhat easy but closing/opening doors, windows and curtains is not so easy, it will require motors and some complications will be involved for achieving this furthermore we have to include temperature/humidity and light sensors also. So i am confused how will I achieve all of this. Please guide me how should I start up. I have to implement my project using Micro Pro C, MP lab, Proteus. And our project involves 3 main parts: 1)Communicate IR sensors with micro controllers. 2)Communicate wirelessly micro controllers with other micro controllers. 3)Communicate wirelessly motors with micro controllers.
    Hopefully waiting for your help Sir.

    • You are welcome, I wish I could help you with all those stages, however the mentioned stages appear quite complex and are not within my easy reach, so I am sorry I won't be able to go beyond the IR remote control stage explanation.

  118. Hello Sir, we have to make this IR remote control for receiving part in our final year project. Our fyp is "Room automation system for disabled persons" in which we have to control electronic equipments like light, fan,AC and non electronic equipments like door, curtain etc…. we have to open/close these mentioned equipments…. so can this remote control circuit given by you can be useful in our project??? please guide me and if any modifications needed, do tell about them. and can u give the code that is burnt in the controller ic in above circuit? waiting for your prompt reply anxiously… thanks. 🙂

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