• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Get free circuit help 24/7

  • 1000+ Circuits
  • Privacy Policy
  • About Us
  • Contact
  • Disclaimer
  • Videos – Circuit Test Results
You are here: Home / Sensors and Detectors / How to Connect a TSOP1738 IR Sensor

How to Connect a TSOP1738 IR Sensor

Last Updated on September 28, 2019 by Swagatam 48 Comments

TSOP17XX series devices are advanced infrared sensors having a specified center frequency of operation which makes their detection extremely reliable and foolproof.

In this post we learn how to connect a TSOP series infrared sensor and use it for a specified IR remote control operations.

TSOP IR Sensor Specifications

A TSOP series of IR sensor ICs may consist many variants which differ marginally from each other, these may be in the form of  TSOP22.., TSOP24.., TSOP48.., TSOP44..

However the most popular and most commonly used is the TSOP1738 IC module which is from the TSOP17XX series.

The other variants from this group are available with the following numbers:

TSOP1733, TSOP1736, TSOP1737, TSOP1740, TSOP1756, TSOP1738CB1, TSOP1738GL1, TSOP1738KA1, TSOP1738KD1, TSOP1738KS1, TSOP1738RF1, TSOP1738SA1, TSOP1738SB1, TSOP1738SE1, TSOP1738SF1, TSOP1738TB1, TSOP1738UU1, TSOP1738WI1, TSOP1738XG1, TSOP1740, TSOP1740CB1, TSOP1740GL1, TSOP1740KA1, TSOP1740KD1, TSOP1740KS1, TSOP1740RF1.

All the above TSOP variants have identical features and characteristics except their center working frequency, which may typically range between 30 kHz to 60 khZ.

How the Connect TSOP1738 sensors

Connecting or wiring a TSOP1738 infrared sensor is actually very easy, once you know how it responds to supply voltage and the IR signals applied across its specified pinouts.

The diagram below shows the a standard TSOP infrared sensor IC, whose pinouts can eb seen marked as (-), (+) and the OUT.

The (+) and the (-) are the supply pins of the IC and are specified to be connected across a 5V typical supply level, to be precise any voltage between 3 and 6V may be aplied here, although 5V works the best, and is recommended since it can be easily tailored using a 5V regulator IC 7805 and allows a wide range of input to be used (between 6V and 24V).

The curved lens which can be seen over the central portion of sensor body is where the infrared signal from a remote control handset is focused for enabling the TSOP to initiate its sensing operations.

Sensor Pinouts

TSOP1738 sensor pinout

NOTE: The pinout polarity is different for the TSOP1838 IR detector, as shown below. So please verify the pinout sequence if you are using a different variant of the IC.

How connect Supply Voltage to TSOP1738

The following image shows how the TSOP1738 IC needs to be wired and connected across a given supply voltage and how its output may be terminated to the relay driver circuit for the intended toggling of the relay according to the sensor's response to the IR signal.

The shown wire connections are for indicative purpose only, these could be in practice connected through PCB tracks.

TSOP1738 connected with 7805 IC

How TSOP1738 Responds to Infrared Signal

Let's learn step wise how a wired TSOP1738 sensor behaves or responds when an IR signal is focused towards its lens.

TSOP1738 sensors without power ON and without input IR

In the above diagram we see that as along as the supply input is not connected to the TSOP circuit, its output stays dormant or inactive, meaning it's neither positive nor negative.

output response of TSOP1738 sensor when power is switched ON

Video Clip

Initially the Output is a +5V (Supply Level)

As soon as the TSOP is applied with a supply voltage (via a 5V regulator), it responds by making its output pin high or at the positive (+5V) level.

This level is maintained, as long as an input infrared signal is not pointed or is focused towards the lens of the TSOP

output response TSOP1738 sensors when powered ON and IR input applied

When an IR Signal is Applied

In the above diagram we can see IR signal frequency being applied and approaching the lens of the TSOP, until it touches the lens of the sensor.

The moment the IR signal reaches the lens of the TSOP, the output of the TSOP begins responding and oscillating in tandem with the focused infrared signal.

The Output Waveform of the Sensor

The output waveform indicates how the output of the IC oscillates between a positive (initial status) and negative (sensing status) across its "OUT" pins in an alternating pattern, as long as the input IR is kept focused towards it.

How to configure the above response from the TSOP1738 sensor for driving a relay stage.

A classic example may be seen in the following diagram taken from the article "remote controlled fish feeder", where we can see the TSOP being used for an IR remote control application and for a toggling action in response to an IR input triggering signal.

Basic Connection Details of TSOP1738 in a Circuit

Simplified Design

Application Schematic for TSOP1738 Relay Operation

working simulation of TSOP1738 in a Circuit

Parts List

R1, R3 = 100 ohms

R4, R2 = 10K

T1 = BC557

T2 = BC547

Relay 12V, 400 ohms

IC = 7805

D1 = 1N4007

Sensor = TSOP17XX

C1, C2 = 22uF/25V

Here we can see that a PNP transistor is being used for toggling the relay, let's learn why exactly a PNP device is required for toggling a TSOP sensor, why an NPN BJT may not be suitable for the same.

Through the above explanation we understood the fact that while the TSOP is in the standby mode or as long as there's no IR signal focused, the output from the device holds a positive potential.

This implies that if an NPN was used in conjunction with this output then this would force the transistor to remain switched ON in the standby mode, and switch it OFF in the presence of an IR signal....

This is technically incorrect because this would keep the relay switched ON all the time and switched OFF only while an IR signal was triggered...this condition is not recommended and therefore we use a PNP transistor which inverts the response from the TSOP sensor and toggle the relay ON only in response to an IR signal, and keeps the relay switched OFF normally while the sensor is in the standby mode (no IR signal).

Here C2 is used to filter the ripples or the pulsating DC output of the TSOP, so that the transistors activate properly and without causing a chattering effect on the relay




Previous: Make this Simple Washing Machine System
Next: Remote Controlled Fish Feeder Circuit – Solenoid Controlled

About Swagatam

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!

You'll also like:

  • 1.  Understanding SG3525 IC Pinouts
  • 2.  Microwave Sensor or a Doppler Sensor Circuit
  • 3.  Buck Boost Circuit Using IC 555
  • 4.  555 LED Flasher Circuits (Blinking, Flashing, Fading Effect)
  • 5.  Non-Contact Cable Tracer Circuit
  • 6.  Opamp Hysteresis – Calculations and Design Considerations

Please Subscribe (Only if you are Genuinely Interested in our Newsletters)


 

Reader Interactions

Comments

    Your Comments are too Valuable! But please see that they are related to the above article, and are not off-topic! Cancel reply

    Your email address will not be published. Required fields are marked *

  1. Search Related Posts for Commenting

  2. T J Bhaduri says

    Dear Sir, I made one Automatic Sanitizer Dispenser with IR( LED based) Proximity Sensor Module ( LM358 based), TIP32C Transistor and DC 6V Submersible pump etc. I want to modify the Project by replacing IR-Receiver LED with TSHOP1738. Because the current model is not suitable in Sun light. Could you please help with a Circuit Diagram with TSOP1738 & Delay function with Relay to minimize the Sanitizer waste. Best regards,

    Reply
    • Swagatam says

      Dear TJ, the TSOP sensor has an extremely high detection range and will detect any object even 5 meters away, so I don’t think this sensor can be applied for sanitizer application.

      Instead you can go for a LM567 based design as explained in the following article:

      4 Simple Proximity Sensor Circuits – Using IC LM358, IC LM567, IC 555

      Reply
      • Tirtha Jyoti Bhaduri says

        Dear Mr.Swagatam,
        Thanks for your Valued comment.I will try and let you know. Regards,

        Reply
  3. vivek srivastava says

    dear sir,
    I built this for a project by adding a relay in output where we wanted to have a NC connection when TSOP receives an IR signal (IR LED) to have a click signal for our fiber laser so that whenever it detects a piece it start to print on it. But this ckt is getting triggered again and again by the LASER while it is printing on the piece because LASER itself is a type of amplified light.
    can you suggest what type of sensor circuit should i use to get a click signal to activate printing by LASER

    Note- our piece to be printed is made of plastic.

    Reply
    • Swagatam says

      Hello Vivek, do you want the relay to switch ON permanently when a laser is detected, or want the relay to click just once ON and OFF, in response to the laser detection?

      Reply
      • vivek srivastava says

        THANKS SWAGATAM FOR RESPONDING.
        we are trying to mimic a foot switch action with this sensor setup. so it will be a 1-2 second ON (NC) CLICK SIGNAL and then off (NO).

        Reply
        • Swagatam says

          No problem vivek, in that case if you add a 10uF or a higher value capacitor in series with the BC547 base resistor, that should do the job for you. Additionally add a 100uF parallel to the relay coil also. The negative of the capacitor will go towards the base of the transistor. The capacitor can be at the left side of R4 or right side R4 does not matter.

          Reply
          • Swagatam says

            If this does not work satisfactorily then we may have to go for an IC 555 monostable version

            Reply
      • vivek srivastava says

        AND we are not detecting LASER. we are just placing a plastic piece which needs LASER marking. the sensor setup is detecting the plastic piece and gives signal to LASER and then printing starts.
        next signal will go to LASER when we put next piece.
        Please note that the relay should remain in OFF (NO) condition untill next piece is kept at the same place after removing the previous place. means while removing the first piece, the sensor should not give signal (NC) to the LASER to avoid burn injuries to the person placing the pieces.

        Reply
        • Swagatam says

          Sorry, without seeing the entire drawing set up it can be difficult to understand the mechanism, and to implement the circuit correctly. By the way N/O is the switch ON condition of the relay and the N/C is the switch OFF condition of the relay

          Reply
  4. Jan says

    Good project.
    But a small remark about the IR receiver is a must do for anybody who might to make this design.

    Pins of TSOP1738 are indeed from left to right Gnd-Vcc-Out.
    But There are many other receivers that have the pins switched.
    Pins of TSOP1838 are for example from left to right : Out-Gnd-Vcc
    I believe that the majority of IR receivers is as TSOP1838
    So if you decide to use another receiver keep this in mind before you boil your receiver.

    Jan

    Jan

    Reply
    • Swagatam says

      Thanks Jan for the information, it’s much appreciated!

      Reply
  5. Husi Rusmani says

    Thanks brother … 😀

    Reply
    • Swagatam says

      Thanks!!

      Reply
  6. Nived says

    Hi sir,
    Thank you for helping me!!
    Can i connect 470ohm parallel to r1 to reduce sensitivity.Also is there any way to add preset to adjust the range/sensitivity of tsop .Actually i’m planning to use this for making automatic water tap.I tried with ir proximity sensor but its range is too short.

    Reply
    • Swag says

      Thanks Nived, R1 is a current limiting resistor for the supply input to the sensor, connecting another resistor parallel to R1 will increase current to the sensor and that will result in the device getting more sensitive, so that won’t work.

      Connecting a resistor across base/emitter of the PNP might help to reduce the sensitivity, however there’s no effective way of achieving this. Another way is to increase the value of R3 or replace it with a preset

      Reply
  7. Nived says

    Also yesterday,you replied me to use t2 as bc547.but that comment is removed.waiting for your reply

    Reply
    • Swag says

      Sorry Nived I am facing some problems with my site, therefore there may be some issues for the moment, by the way I have corrected the the BC557 with BC547

      Reply
  8. Nived says

    Hi sir,
    I made the relay based circuit ,but the problem is that the relay keeps on triggering.When i use the remote,triggering stops.when i move the remote away,it again starts triggering

    Reply
    • Swag says

      You mean, the relay stays ON when the remote is not activated? and OFF when the remote is activated…

      Reply
      • Nived says

        Exactly sir,
        Relay keeps on trigering.when the remote is activated,it stops.like that

        Reply
        • Swag says

          Nived, the relay should switch ON only when remote is shown towards the sensor. Connect an LED in series with R4 this will tell you how the circuit is responding.

          The sensor output iis supposed to go low when IR is present from remote, and will remain high in the absence of IR (no signal). BC557 will switch ON only when the sensor is low.

          Reply
          • Nived says

            Hi sir,
            Now it’s working perfectly.
            I have one doubt,i used to see a diode connected across relay in most of the circuits.what is its purpose?
            .will the circuit operates perfectly without that diode??

            Reply
            • Swag says

              That’s great Nived!
              The diode is called the freewheeling diode or the flyback diode. It makes sure that whenever the transistor switches OFF the relay, the back EMF or the reverse current surge generated by the relay coil is short circuited and eliminated through this diode. Not including this diode will force this current through the transistor and quickly damage the transistor.

            • Nived says

              Ok sir thank you,
              Is there any way to reduce the sensitivity of tsop

            • Swag says

              yes, you can try adding a 220 ohms or a 470 ohm resistor across base emitter of BC557 or R1.

            • Nived says

              Also can i use 1N4148 diode across relay

            • Swag says

              For small relays like a 400 ohm relay 1N4148 will do, no problems.

  9. JAYANATH says

    dear sir
    i want to make IR beam barker alarm circuit.
    it means IR beam continuously fall on the TSOP and the relay to be on, if some one cut the IR beam
    request instructions for circuit
    thanks

    Reply
    • Swag says

      Jayanth,

      you can try the following concept:
      https://www.homemade-circuits.com/remote-controlled-fish-feeder-circuit/

      for the transmitter you can use an IC 555 based astable set at 38kHz frequency, and connect any photodiode across its pin#3 and ground, then focus the beam on the TSOP sensor…make sure to add a 470 ohm resistor in series wit this LED

      Reply
      • JAYANATH says

        sir i have gone through above fish feeder circuit. but,, in my concept ir beam continuously fall on the tsop and i want to switched the relay when ir beam disturbed. i already made 38khz circuit also. any alteration to fish feeder mechanism circuit?

        Reply
        • Swag says

          Jayanth, you can keep the 38kHz beam continuously focused on the TSOP, no alteration would be required since it is exactly as per your requirement.

          Reply
          • JAYANATH says

            yes sir but relay is always in contact. and relay will be disconnect i\only when ir beam is interrupted. that will effect to the relay coil during long time operation. so want to relay to be contact only when ir beam is interrupted sir. request instructions

            Reply
            • Swag says

              Jayanth, for this you can do the following modifications:

              remove the relay from the existing position and replace the points with a 10K resistor.
              take another BC547 transistor, connect its base with the existing BC547 collector, emitter with the ground line, and now connect the relay across this new BC547’s collector and the positive line.

              Make sure to add the 1N4007 with the relay coil.
              this will invert the switching condition as desired by you.

            • JAYANATH says

              ok sir i will do and reply you

            • JAYANATH says

              sir i have made it . it is working perfectly with abans tv remote. but it is too sensitive. i have to fully block the IR led by finger , to cut the beam. how to decrease the sensitivity of TSOP ?

            • Swag says

              Hi Jayanth, try enclosing the TSOP inside an opaque pipe, such that the transmitter beam is able to hit the sensor only when it is aligned with the mouth opening of the pipe. In this way you might be able to achieve the desired results.

            • JAYANATH says

              dear sir
              circuit is working fine. thanks sir. And also i want to latch the output. i mean when some one breaks IR beam the relay to be in contact till power off.

            • Swag says

              That’s great jayanth,

              to latch you can connect a diode between the base of the middle BC547 and the collector of the relay driver BC547. Cathode will go to the collector.
              Also connect a 1K resistor across the base and ground of the middle BC547 transistor.

              But remember, with this arrangement the circuit will be latched initially when power is switched ON. You must have switch in series with this diode so that you can keep the diode disconnected initially and switch it ON only once the IR beams is correctly focused on the TSOP.

            • JAYANATH says

              ok sir thank you i will do that

  10. Daniel says

    Where is the parts list ?

    Reply
    • Swag says

      updated now!

      Reply
      • JOÃO says

        REALLY ENJOYED! YOU EXPLAIN VERY WELL, CONGRATULATIONS! I WOULD LIKE TO KNOW THE DIFFERENCES THERE ARE OR NOT OF THESE TSOP, IN RELATION TO TSOP 1838,
        BECAUSE I HAVE SOME OF THIS KIND…

        Reply
        • Swagatam says

          Glad you liked them! They all have similar characteristics and features except the central operating frequency which may range from 30 kHz to 60 kHz.

          Reply
  11. Santhosh Pamparthi says

    Hi
    I am planing to do some simple project with tsop sensor interfacing to 8051 controller. Here we are using like TV remote, for each button in remote, am planing to do some task, how can i read the each button of remote values to write program

    Reply
    • Swagatam says

      Hi, if it's possible I'll try to post the details it in this website soon…

      Reply
  12. Achesit Christian says

    PLEASE HOW CAN I KNOW WHEN THE TSOP DEVICE IS BAD. ARE THERE DIFFERENT WAYS OF CONNECTING OTHER TSOPS APART FROM THE METHOD YOU HAVE PRESENTED

    Reply
    • Swagatam says

      there's only one way of connecting these ICs as illustrated in the above diagrams. check the output voltage in response to a IR beam input…

      Reply


  13. COMMENT BOX IS MOVED AT THE TOP


Primary Sidebar

Electronic Projects Categories

  • 3-Phase Power (15)
  • 324 IC Circuits (19)
  • 4017 IC Circuits (51)
  • 4060 IC Circuits (25)
  • 555 IC Circuits (92)
  • 741 IC Circuits (18)
  • Amplifiers (49)
  • Arduino Engineering Projects (82)
  • Audio Projects (83)
  • Battery Chargers (75)
  • Car and Motorcycle (87)
  • Datasheets (44)
  • Decorative Lighting (Diwali, Christmas) (31)
  • DIY LED Projects (81)
  • Electronic Components (96)
  • Electronic Devices and Circuit Theory (34)
  • Electronics Tutorial (99)
  • Fish Aquarium (5)
  • Free Energy (34)
  • Games (2)
  • GSM Projects (9)
  • Health Related (17)
  • Heater Controllers (23)
  • Home Electrical Circuits (98)
  • Incubator Related (6)
  • Industrial Electronics (25)
  • Infrared (IR) (39)
  • Inverter Circuits (94)
  • Laser Projects (10)
  • LM317/LM338 (21)
  • LM3915 IC (24)
  • Meters and Testers (52)
  • Mini Projects (152)
  • Motor Controller (64)
  • MPPT (7)
  • Oscillator Circuits (12)
  • PIR (Passive Infrared) (8)
  • Power Electronics (32)
  • Power Supply Circuits (64)
  • Radio Circuits (9)
  • Remote Control (46)
  • Security and Alarm (55)
  • Sensors and Detectors (115)
  • SG3525 IC (4)
  • Simple Circuits (72)
  • SMPS (30)
  • Solar Controllers (60)
  • Timer and Delay Relay (51)
  • TL494 IC (5)
  • Transformerless Power Supply (8)
  • Transmitter Circuits (36)
  • Ultrasonic Projects (12)
  • Water Level Controller (45)

Follow Homemade Circuits

Facebook
Twitter
YouTube
Instagram
My Facebook-Page
Quora

Feeds

Post RSS
Comment RSS

Circuit Calculators

  • AWG to Millimeter Converter
  • Battery Back up Time Calculator
  • Capacitance Reactance Calculator
  • IC 555 Astable Calculator
  • IC 555 Monostable Calculator
  • Inductance Calculator
  • LC Resonance Calculator
  • LM317, LM338, LM396 Calculator
  • Ohm’s Law Calculator
  • Phase Angle Phase Shift Calculator
  • Power Factor (PF) Calculator
  • Reactance Calculator
  • Small Signal Transistor(BJT) and Diode Quick Datasheet
  • Transistor Astable Calculator
  • Transistor base Resistor Calculator
  • Voltage Divider Calculator
  • Wire Current Calculator
  • Zener Diode Calculator

© 2021 · Swagatam Innovations

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.Ok