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More  Beepers & Buzzers Circuits

Check Engine Beeper - June 30, 2006
designed by David A. Johnson, P.E.

 

When driving down a busy road, you may not notice a “check engine” indicator light that suddenly turns on within the car’s instrument panel.  You could drive for many miles before noticing the light.  To provide an audible indication of trouble, the hobby circuit below could be added.

When connected to a typical automotive check engine indicator light on the instrument panel, this circuit will sound a loud beeper, when the light turns on.  the hobby circuit counts on the fact that most check engine signals swing from chassis ground potential to +12v.  When the signal is at 12v it turns on, the n-channel FET which activates the beeper. 

Click on Drawing Below to view PDF version of Schematic

Circuit Check Engine Beeper Circuit designed by Dave Johnson, P.E. (June 30, 2006)

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