When the carīs signal light blink, the clicking sound of its mechanical controller can be heard.
This click serves as an acoustic feedback for the driver to know whether the signalling system is working or not.
In electronic systems, however, the blinking of the carīs signal light is electronically controlled and therefore no clicking sound is produced.
This absence of acoustic feedback makes the driver wonder whether
his signal lights were really blinking. To solve this problem, the circuit here was designed. It provides a "clicking" sound in synchronization with the blinking of the signal lights.
Instead of producing a rough click, however, it produces a pleasant tone everytime the signal light blinks. The tone's volume can be varied by using a different value for R3
(minimum = 68 ohms). You can also change the toneīs frequency by changing the value of C1. The switch S in the circuit is actually the built-in signal switch in the car.
Parts Placement Layout
Electronic Circuits volume 1.0 - Circuit Nr. 95
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
Click on the image to view the book.