Reverse Car Parking Sensor Circuit


BySaddam 84

Reverse Car Parking Circuit using IC LM358

This car parking assistant can protect your car from any damage while reverse parking. It indicates the distance of car from any object and raise an alarm when it reaches close to the wall or the object and needs to be stopped. This car parking sensor circuit is quite easy and uses few commonly available components which are listed below.


Required Components

  • IC LM358 - 2
  • 10k Resistor  - 1
  • 1k Resistor - 3
  • 10k POT - 3
  • 150 Ohm Resistor - 1
  • Bread board - 1
  • 9 Volt Battery  - 1
  • Battery Connector - 1
  • LED  - 3
  • Buzzer - 1
  • IR Pair - 1                


LM358: LM358 is a Dual Low Noise Operational Amplifier which has Two Op-Amp in a single chip. This is a general purpose op amp which can be configured in many modes like comparator, summer, integrator, amplifier, differentiator, inverting mode, non- inverting mode and many more.


To design this car parking system circuit, we placed an IR transmitter receiver pair at the rear side of the car. IR transmitter transmits Infrared signal or rays into the environment continuously. When these transmitted IR rays reflect back to IR Receiver after striking on an obstacle, some voltage difference generates across this IR receiver LED. This generated voltage difference depending upon the power of IR rays that are reflected back to the receiver. More powered signal leads to more voltage difference. This voltage difference is used in our project to measure the distance. Here more voltage difference indicates the lesser distance from the object. Here we have shown distance from the obstacle by using three LED’s. Meaning of these LED’s are explained in working of this project.

Block Diagram for Reverse Car Parking Circuit


Circuit Diagram and Explanation

In this car parking circuit we have used an IR pair for detecting obstacle and two LM358 Dual Comparator ICs for comparing voltages. Comparator configured in non-inverting mode and 10 K potentiometer is connected at its inverting terminal for adjusting reference voltage and IR receiver’s Output is directly connected at non-inverting pins of all comparators. One Red LED is connected at output of U1:B IC(LM358), a Yellow LED is connected at output pin of U2:A IC(LM358) and an Green LED is connected at output pin of U2:B IC(LM358) through a 1K resistor. A buzzer is also added at Red LED.

 Car Parking Circuit Diagram



We have shown the reference voltage and relative parameters in the below table. But one can set distance by changing the value of potentiometer.

Obstacle v/s Vehicle

LED status

Reference Voltage


not close



Greater than 15 cm


Green ON

2.0 Volt

About 15 cm

More Close

Yellow ON

4.0 Volt

About 10 cm

More Close

Red ON

6.0 Volt

About 5 cm


Car Damaged


About 0 cm


This system is placed at the rear of the car and sensor’s front side toward the obstacle (wall). Now suppose car is moving back toward the wall or obstacle in the parking slot. If distance between car and obstacle is more than 15 cm then no LED will glow. Now if car moves toward the obstacle and suppose greed light turned ON, it means car is about 15 cm away from the obstacle. Now car is moving more close toward the obstacle and yellow light appears or turned on it means car is about 10 cm away from the obstacle. Now car is moving closer toward the obstacle and red light appears it means car is about 5 cm away from the obstacle and same time buzzer start beeping. Buzzer and red light indicates that the car need to stop now otherwise car may be damaged.



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  • yashraj's picture
    Nov 22, 2015

    we made the exact circuit on the bread board but we are not getting proper sensing through the ir pair we checked the ir pair its not faulty . when we place the power supply all the leds are glowing even if we remove the resistor all the leds are glowing what shall we do to make sure one led glows at a time and we get proper sensing

  • Maddy's picture
    Nov 28, 2015

    The circuit is correct, you need to adjust the values of three potentiometers by rotating the knob, Rotate the knobs until LEDs get turned OFF, now take some object in front of IR pair, LEDs should get turned ON. Now you should set the sensitivity of three LEDs separately by rotating the respective knobs, like Green LED should be most sensitive and Red LED should be least sensitive.

  • Simjin Manohar's picture
    Simjin Manohar
    Dec 09, 2015

    How can we increase the sensing distance to about 75cm

  • Maddy's picture
    Jan 01, 2016

    75cm can be obtained from this circuit, otherwise provide LED the optimal(max) power supply or use convex lens at photodiode or use a powerfull IR LED. Also try using 100k variable resistor to this circuit.

  • Özge's picture
    Dec 17, 2015

    We set circuit on the breadbord but we can not change volt for each led by potantiometer. How we can operate this circuit

  • sankha dey's picture
    sankha dey
    Dec 20, 2015

    I made it .but it works opposite.

  • Maddy's picture
    Jan 01, 2016

    Change the sensitivity for the LEDs by adjusting Potentiometers, with Green most sensitive. You can check this Circuit for clear understanding of IR sensor working: IR Sensor

  • sankha dey's picture
    sankha dey
    Jan 10, 2016

    I do not understand.

  • KILTON ROY's picture
    Feb 24, 2016

    sir i do not understnd the circuit u have upload and original circuit

  • saddam khan's picture
    saddam khan
    Feb 25, 2016

    what problem are you facing?

  • KILTON ROY's picture
    Mar 10, 2016

    sir kindly tell me specification of recve resistr and what is the fuction of second ic lm358 there u did pin num 3 and 5 short but why? circuit mention correctly plese sir? i need this for my final year projt? so plese hele me sir

  • david's picture
    Feb 26, 2016

    In the circuit there are only 2 ICs shown but in the circiut diagram i can see 3 why is it so. Am i reading the diagram wrong

  • saddam khan's picture
    saddam khan
    Feb 26, 2016

    there is only two IC's are used.
    here we have used LM358 which is dual op-amp IC.
    mean single IC consists two op-amp inbuilt.
    so here is four op-amp but we used three of them.

    for more detial read data sheet of lm358.

  • adi's picture
    Jun 24, 2018

    yes. but in the schematic every single op-amp have its own 8 & 4 pin. so its 3 different ic's??
    (sorry for bad english)

  • Jayant's picture
    Jun 25, 2018

    If you are using LM358 then each IC will have two Op-amp inside it. So totally you will need two op-amp. Or you can use a Quad op-amp package 

  • KILTON ROY's picture
    Feb 26, 2016

    sir there you used 150ohm or 10 k resiston on recver diode and what is the specification of pot have used sir ?

  • Kay Hanes's picture
    Kay Hanes
    Mar 03, 2016

    I have been trying to get this circuit to work and it seems to work opposite, turns off when something is very close and on all the time. I adjusted the pots and it doesn't fix it. Also, the schematic is not correct for using a 150 Ohm resistor in the call out, it shows 2 10K. Can you please help me?

  • Maddy's picture
    Mar 12, 2016

    You must have messed up with the inverting and non inverting ends of op amps, you have connected terminal + connections to - terminal and vice versa. I recommend you to read about LM358, it is a dual opamp IC, in which we have used 2 opamps of one IC and 1 opamp of another IC, means we have used total 3 op amps out of 4 from 2 LM358 ICs. Please go through its datasheet and understand the working of an Op-amp IC.

  • hai's picture
    Mar 08, 2016

    Hi I bought aftermarket car parking sensor device
    I install in front bumper. Too much noisy. I plan to reduce rage from 2 meter distance to 1 meter distance . any help that I can do something on the circuit board

  • Jack's picture
    Mar 12, 2016

    Hi there! In the above circuit we have 1 Tx and 1 Rx sensor. Would be possible implement 2 or even 3 pairs of Rx/Tx?

    Thanks in advance,

  • KILTON ROY's picture
    Mar 13, 2016

    sir can u tell me what is the frequency range transmit from the transmitter via infarred led and voltage value? and also at that time reciver point voltage value is what? sir kindly tell me ? this is my final year project? and also there are non inverting pin also short sir?

  • Jayant's picture
    Mar 28, 2016

    Infrared Frequency range is about 300 GHz - 430 THz, and voltage at the Receiver may vary from 0 to 9v depending upon the closeness of object to the IR pair. Learn more about IR sensor here: IR Sensor Module Circuit

  • francis lepcha's picture
    francis lepcha
    Mar 18, 2016

    i cant see the pot in the circuit

  • Pranav's picture
    Mar 20, 2016

    Sir, thank you for the circuit and the explanation
    I want to know if we could make the same circuit sound when each LED glows

  • Jayant's picture
    Mar 28, 2016

    yes, just connect more buzzers with other two LEDs, like the last one.

  • pankaj's picture
    Apr 06, 2016

    Can we use LM324 in place of two LM358.

  • Maddy's picture
    Apr 18, 2016

    yes, but check its pin configuration and datasheet.

  • Teddy's picture
    Apr 27, 2016

    Instead of IR pair can ultrasonic sensor be used?
    Which would have better accuracy?

  • David's picture
    May 05, 2016

    Maddy can you upload the maths calculations of how resistance you put at the potenciometers related with the voltage? Thank you

  • vadlamudi sydeswera rao's picture
    vadlamudi sydes...
    May 14, 2016

    dear sir ;

                      i need to change distances  green  is 30cm , yellow   is 15cm and  red is 5cm it's possible .if it's possible please tell me about this,,,

           thank you ;

           v.s rao.



  • Maddy's picture
    May 17, 2016

    @David @vadlamudi: 10k pot is generally used with IR pair, you can use more or less according to the sensitivity range. And distance can be set manually by keep rotating the pot and check the LED at the same time. Also check this circuit to understand the IR Sensor Module Circuit

  • hamza rehman 's picture
    hamza rehman
    May 29, 2016

    Thanxx Bro this ciruit is in working condition but it takes lot of hard work ..

  • Arang Ariawan's picture
    Arang Ariawan
    Jul 02, 2016

    "I have to try,all your instruction but very close not more 15cm.
    Any solution to make more 50cm..thnk's

  • Maddy's picture
    Jul 12, 2016

    This question is already answered above. 50cm can be obtained from this circuit, otherwise provide LED the optimal(max) power supply or use convex lens at photodiode or use a powerfull IR LED. Also try using 100k variable resistor to this circuit.

  • sankha's picture
    Aug 08, 2016

    It works at day light. but at night ,when the light is low it works very badly..
    Sir , please help me..

  • ASHISH A. KUMBHAR's picture
    Aug 13, 2016

    We build the ckt & we got the same results thank you

  • ASHISH A. KUMBHAR's picture
    Aug 22, 2016

    150Ohm register is burning while operating the ckt we got the same results but as time pasing the ckt sensitivity is changing and 150 ohm register is burning please help us
    What modification we have to do?

  • Abhishek's picture
    Aug 22, 2016

    What power supply are you using, please use 9v general purpose battery as mentioned, it should not burn with 9v battery.

  • ASHISH A. KUMBHAR's picture
    Aug 23, 2016

    Yes We used 9v power supply but it is still burning as time passing & ckt sensitivity is changing as time passing for every trial we have to adjust the presets what should we do

  • Abhishek's picture
    Sep 17, 2016

    Replace the 150 ohm resistor with 1k resistor and use some constant power supply like 5v adapter.

  • shanthi's picture
    Sep 07, 2016

    How can this concept be reversely operated as buzzer for long distance indication and no sound for short distance pls reply soon

  • charlie's picture
    Nov 06, 2016

    Maddy ,,
    What is the potentiometer value we want to keep for glowing the LED......

  • Bharath's picture
    Nov 07, 2016

    Sir I have did the project but not on bread board I did the project on general purpose circuit came very well..sir I want u to see the model..

  • shani pratap singh's picture
    shani pratap singh
    Sep 07, 2018

    Would you like to show. I want to see your circuit please

  • Aashiq Mohamed's picture
    Aashiq Mohamed
    Nov 09, 2016

    The buzzer is not working when I simulated it in Proteus. When I connected it in parallel with the LED, it stops working.

  • Abhishek's picture
    Dec 02, 2016

    Proteus Simulation Video is also given above, please check.

  • Themiya Neranjana's picture
    Themiya Neranjana
    Nov 18, 2016

    made it and its working perfectly.

  • Saqib's picture
    May 22, 2017

    We made it but the problem is IR pair is not work.plz help us what should we do?

  • sidra's picture
    Nov 28, 2016

    How we can detect the pole behind the left and right rear lights?
    In which configuration we can use two other IR sensors for detecting the pole described above?
    plz reply me as early as possible

  • sidra's picture
    Nov 29, 2016

    is this circuit valid for 3 IR sensors?

  • jp's picture
    Nov 30, 2016

    All the nights glow during day time, but when at night, it works properly. What should we do? Thanks

  • Mustafa's picture
    Dec 06, 2016

    sir, please can your send me the pcb design of this circuit.

  • Aletrina's picture
    Jan 20, 2017

    Hello, does someone know about how long does the battery will last? Or can I power this circuit from my car battery?

  • CC's picture
    Feb 20, 2017

    Hi, we made the exact circuit, and once the power supply is connected all the LED's are glowing, then by rotating each potentiometer knob all LEDs turned off. What to do next? how to set the sensitivity of each LEDs?

    em expecting your reply soon, thank you! ^_^

  • Em-m's picture
    Mar 11, 2017

    Hello, we also made the exact circuit, but everytime we're connecting the power supply, the leds just keep on glowing. We tried turning the knobs of the trimmers but the glowing leds are still turned on. Please helppp. Thank you!

  • prabha's picture
    Mar 17, 2017

    connection are correct but LED is not glowing. what should we do now?

  • subramanya's picture
    Mar 21, 2017

    how to connect the pots to the opamp?i am confused regarding the connections of pin 8 and pin 4

  • usman's picture
    May 12, 2017

    Can you please send me a clear picture off ur breadboard thanks

  • Navaneeth M's picture
    Navaneeth M
    May 14, 2017

    Can we use SM3388 as the reciever??

  • Amir's picture
    May 30, 2017

    Hello sir, I have made the circuit as per the diagram. But all the LEDs are glowing together at 5 cm. The LEDs are not glowing at 10 and 15 cm. What should I do?

  • abcd's picture
    Aug 11, 2017

    worked flawlessly thanks

  • joel's picture
    Oct 17, 2017

    would u pleas send me images of ur circuit

  • joel's picture
    Oct 15, 2017

    sir y u put 3 ics in the circuit and on the breadboard only two?

  • AISHA's picture
    Oct 17, 2017

    Take a close look at the name of IC in circuit diagram. They are U1A and U2A and U2B.

    This means that there are only two IC U1 and U2. Since LM358 is a dual package op-amp it has both U2A and U2B inside it. Similarly U1 also has A and B, but we have left U1B to be free

  • Hassan's picture
    Dec 03, 2017

    I've made the same circuit on proteas as well as on bread board but both of them aren't working.

  • HR Rufus's picture
    HR Rufus
    Dec 10, 2017

    Can I know how many people have made this and succeed? Because I am having a problem because the LED keeps turned on even though I already change the sensitivity on the pot. Can someone help me with this?

  • Aswinth Raj's picture
    Aswinth Raj
    Dec 11, 2017

    The circuit seems to be fair. So everyone should get it working as the author has demonstrated. If you facing any trouble its most likely with your connections. Use a multimeter to debug your circuit

  • tom 's picture
    Feb 05, 2018

    what does the D5 do because i am lost on how the it can have the negative is connected to the positive

  • Saqib Sami's picture
    Saqib Sami
    May 08, 2018

    I made this project as my 5th semester project. The circuit was working good.
    Thanks Sir .

  • DRUMZ's picture
    Jun 05, 2018

    @saqib Sami when i simulate this on proteus immediately i press play it =immediately displays a one instead of zero
    what could be causing this ?

  • Samriddh's picture
    Oct 14, 2019

    Bro. Can you please send me your mail id cause I want help in hardware part. Actually all 3 led are glowing when the circuit is on. What did you do to make it right!?

  • Samriddh's picture
    Oct 14, 2019

    Bro. Can you please send me your mail id cause I want help in hardware part. Actually all 3 led are glowing when the circuit is on. What did you do to make it right!?

  • Samriddh's picture
    Oct 14, 2019

    Bro. Can you please send me your mail id cause I want help in hardware part. Actually all 3 led are glowing when the circuit is on. What did you do to make it right!?

  • Samriddh's picture
    Oct 14, 2019

    Bro. Can you please send me your mail id cause I want help in hardware part. Actually all 3 led are glowing when the circuit is on. What did you do to make it right!?

  • Abuzar's picture
    Jun 10, 2018

    Any one of u have any idea about pcb of reverse car parking sensor plzzz guide me

  • Muhammad abuzar's picture
    Muhammad abuzar
    Jul 09, 2018

    hey guys what did you think its a correct circuit??? its not a correct circuit. he has used 2 ic's on bread board.while there are 3 ic's on proteus schematic format.

  • Samriddh's picture
    Oct 12, 2019

    Hey! I am unable to make the circuit in Multisim. Can anyone send me the design either on Multisim or proteus for simulation??

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