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Display buzzer Answered

I am not good at designing electronics. Could someone point me in the direction of a suitable circuit to do this... I have a device with a backlight on an led display, the backlight is normally on but can be switched off sometimes the backlight flashes to alert the user. on for 1 sec, off for 1 sec approx. I want to add a circuit to it without changing the existing circuitry when the backlight comes on I want a buzzer to sound for 1/2 sec if the backlight is on then nothing happens, nor should it buzz when the light goes off. So: 1. switch on device, backlight comes on, Buzz 2. backlight is on for length of time but no buzzing 3. backlight starts flashing 4. goes off, No buzz 5. goes on, Buzz 6. repeat from 4 until the backlight stays on this circuit and buzzer is going to have to be very compact to fit in the device. I might substitute a phone vibrate for the buzzer. Any suggestions ?


Packaging is going to be quite difficult but I will think about that when I have an idea of what components are involved.

Are there any buzzers that actully do buzz rather than just sounding the signal sent to them ?  ie. ones that don't need to be driven by a 555 or similar. I thought a digital watch type beeper might work.

The buzzer is the easy part provided I can find one small and loud enough. For me the tricky part is designing the circuit that will detect the rising voltage on the backlight and then sounding the buzzer for the pre-set time. A 555 timer can do things like this, the circuit may require more than one. There is probably a more elegant solution.

Can you post a picture of the area around the display. and you probably also want to buy a piezo buzz unit in order to accomplish this.