Musical car reverse horn circuit

admin November 10, 2011 15 Comments

Description.

Here is a simple circuit that will produce a musical horn when ever your car is in reverse gear.The circuit uses two ICs for the operation, voltage regulator 7805(IC1) and musical tone generator UM66(IC2). The IC1 reduces the car battery voltage to 5V. The diodes D1 & D2 in combination  produces an additional  drop of 1.4 V to give a 3.6 V supply for the UM66. The supply voltage of UM 66 should not  be more than 4V. When ever the car is in reverse gear ,the reverse gear switch of the car gets activated and the circuit gets connected to the car battery. The UM66 starts playing the music tone. The transistor T1 amplifies the output of UM66 to drive the loudspeaker.

Circuit diagram with Parts list.

musical-car-reverse_-horn-circuit

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Notes.

  • Assemble the circuit on  a good quality PCB or common board.
  • Place the circuit on a waterproof place in the dashboard.
  • The switch S1 is the reverse gear switch of the car.
  • Before attempting the circuit,have  a good idea about the electrical wiring of your car.A wrong connection may damage your car’s electricals.
  • The transistor Q1 is not very specific.Any medium power NPN  audio transistor will do the job.You could easily find one from your electronics junk box.
Comments
  • seetharaman
    November 4, 2011

    Hi Patil the sound is loud enough. if you want still higher use use a darling-ton transistor like TIP122 for Q1.

  • kiran patil
    November 3, 2011

    hi!!!!!!!!
    does it have a loud sound.please tell me fast.

  • Patrick vaz
    June 26, 2011

    Hi Seetharaman,

    Thanks, The sound is awesome!!

  • Seetharaman
    June 20, 2011

    Hi Patrick IC1 & IC2 Pins are indicated correctly.
    please refer pins to datasheet
    http://electroschematics.com/6357/um66-datasheet/

  • Patrick vaz
    June 19, 2011

    Hi Seetharaman,

    Just a small doubt, should the pins 1 & 3 to be interchanged, so that pin 1 is grounded and pin 3 goes to the base of the transistor via resistor R2.

    its a very good circuit, suitable as revers alarm(with music)in car, i made the circuit using ic556 but the sound is very annoying.

    Pls Clarify,

    thanks

  • Seetharaman
    October 6, 2010

    Hi Prdeep you cannot program UM66 instead there afre programable ic with “mic-in” use one of those ics and enjoy fun. you can try one of this or so many varients available in indian market (used in manthra chanting box)
    http://www.eetasia.com/ARTICLES/2003APR/A/2003APR04_MSD_MPR_EMS_AN.PDF?SOURCES=DOWNLOAD
    http://www.electronics123.com/s.nl/it.A/id.499/.f?category=2

  • pradeep
    October 5, 2010

    How can i load my personal music in to the IC and in which format it should be loaded.

  • khan salman
    April 14, 2010

    any idea what is the value of R1?

  • pitong
    February 12, 2010

    any idea what is the value of R1?

    • admin
      February 15, 2010

      R1 is 100 ohms .

      Now it is there in the circuit diagram

  • December 15, 2009

    I WANT THE NOTES ABOUT THE CAR REVERSE HORN BECAUSE I HAVE TO SUBIT THE PROJECT IN MY COLLEGUE SO I PLESASE REQUEST YOU SEND ME SOME NOTE ABOUT THIS ON MY E MAIL ADDERS
    ISHAN SHARMA14@YAHOO.IN

  • mike
    June 16, 2009

    Hi just wondering what program you drew the circuit on thanks mike

    • admin
      June 16, 2009

      PCB123

  • November 21, 2008

    Need the PCB layout

  • November 21, 2008

    Thanks for the ccts. Need the PCB layouts.

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