Piezo transducer complication

[John Murdock]

I am using a piezo transducer and I would like to make it somewhat more sensitive somehow or any other way of fixing this:

Problem: Piezo works when I tap it with my finger however it does not do anything when it is tapped by a metallic object which is hitting it with less cross sectional area however with the same force. in application the piezo is meant to be hit by a metallic object and not my finger, any ideas?

Is there something I'm missing ?

Thanks for your help, any ideas are welcome!

 

[cowboybob]

...tapped by a metallic object which is hitting it with less cross sectional area ...

My emphasis.
How does the piezo react when tapped with a larger cross sectional area metallic object?

 

[John Murdock]

My emphasis.
How does the piezo react when tapped with a larger cross sectional area metallic object?

Nothing. cross sectional area in regards to the metal doesn't seem to be a factor.

 

[cowboybob]

OK.
Some additional info would be nice, i.e.,

-Piezo specs
-How is piezo mounted
-Peizo output level when tapped with your finger
-Peizo output detection method
-What is the metallic object.

Anything else that helps describe your circuit.

 

[alec_t]

Perhaps the piezo output is being short-circuited via the metal and your body? You could test this hypothesis by providing an insulation layer between metal and body.

 

[John Murdock]

It works when the anode and cathod wires e of the piezo are in a certain position so I guess I have to keep it in that position..

 

[cowboybob]

JM, I'd be interested in seeing a picture of what you described in the post above.

Just curious...

 

[John Murdock]

JM, I'd be interested in seeing a picture of what you described in the post above.

Just curious...

At home now will post a pic when I get my hands on it early morrow.

 

[Externet]

Is the amplifying/sensing circuit input impedance of the proper MΩ magnitude ?

 

[John Murdock]

Is the amplifying/sensing circuit input impedance of the proper MΩ magnitude ?

Truth be told I have no idea what that is. (still a noob)

 

[large_ghostman]

Is it a round sensor with a white patch on one side and two wires on the side of the white bit? If so turn it over

Sorry that was rubbish description! is it like this kind of sensor?

If so they work better if you turn them over to the plain metal side and bang that

 

[John Murdock]

Yep that's it.
Isn't it the piezo material which is tapped that makes it work and the brass around it is for conduction ?
so technically you need to tap the piezo material rather than the metal?

 

[large_ghostman]

I found the white bit gets damaged, mine have seemed to work better if i tap the back (the bronze bit).