Car Horn Circuit Description:

This car horn circuit reproduces the sound of contemporary vehicle horns. It had been mainly created for models and toys but, applying a high output energy audio amplifier IC, it could be implemented as well in further complicated projects.
Circuit operation

To receive a realistic automobile horn sound, two different tones mixed collectively are essential and the interval they’ll type ought to be a so known as minor third (in musical terms). This can be implemented by two 7555 CMos Timer ICs wired as astable multivibrators and generating a square wave of about 440Hz and 523Hz respectively. These frequencies ought to be quite precise, so the uncommon values necessary for your timing resistors are obtained by wiring two common worth resistors in series.

The square wave frequencies produced by IC1 (440Hz) and IC2 (523Hz) are mixed via R5 and R6 and shaped by C3, C4 and R7 in order to obtain a far more realistic tone. The resulting composite audio signal is ultimately sent for the audio power amplifier IC3 which, in turn, drives the loudspeaker. R7 needs to be adjusted to acquire a satisfactory output level.

Car Horn Circuit Notes:

• The loudspeaker may be of any form and diameter. Certainly it need to withstand a energy of at the least 1 Watt if the TDA7052 Audio power amplifier IC is chosen.
• The TDA7052 IC was used since it permits a minimum parts count and very excellent functionality. Wanting to make use of a distinct audio power amplifier IC, you are able to pick the much less effective but straightforward to find LM386 (see the Cuckoo-song Generator project).
• In any case, try a great sized device, as a way to receive finest outcomes.
• Needing a a lot more effective amplifier chip, it is possible to use the TDA2003 10W Car Radio Audio Amplifier IC or the TDA1516BQ 24W BTL Vehicle Radio Power Amplifier IC .

Source: RedCircuits