Hello and thank you.
I have an analog output accelerometer board from ST micro (511-STEVAL-MKI014V1) that I would like to trigger an adjustable momentary audio alarm if the output reaches a desired level. Could anyone offer suggestions to a person with little electronic experience?

 

I think the most important question is what kind of alarm did you have in mind? There are buzzers that will beep if you put a current through it, which you could probably drive with the output of a comparator. The comparator could have an adjustable threshold.

If you want to have a more complicated alarm, it will probably take a more complicated circuit to drive it.

 

Agreed. If you have only a speaker, or piezo, you will need to trigger a frequency generator. A simple 555 circuit will handle this task.

If the alarm speaker is "bigger" than a hobby-sized speaker, you will also require amplification.

 

Agreed. If you have only a speaker, or piezo, you will need to trigger a frequency generator. A simple 555 circuit will handle this task.

If the alarm speaker is "bigger" than a hobby-sized speaker, you will also require amplification.

Thank you that is exactly what I want a small piezo with 555. Can you send me any links to what you might have in mind? Again many thanks!

 

Here is a simple thread to follow in our Projects Forum:
http://forum.allaboutcircuits.com/showthread.php?t=26651

 

Thank you retched...any suggestions on how I control the trigger level from the accelerometer, in other words how do I enable that piezo circuit to buzz at 4g's or 2.5 g's? I believe earlier there was some talk of a comparator...