Question with piezos and LED's

[fbchurch2009]

I am trying to get some LED's to light up when I hit my drums. I can light up the LED's just fine with a battery, but when I hook a piezo transducer to my drums and strike them, the LED's barely light up... how can I get the LED's to light up all the way when I hit them? I am thinking it is the sensitivity of the piezo transducer? is there any practical way to get this to work? I am not really knowledgeable so please explain things thoroughly. thanks!

 

[Resqueline]

The piezo transducers have a very high voltage output when you hit them but can only deliver a very small current (= high impedance). They have a capacitance of around 2nF which means they can deliver power to the LED for only a very short time too.
One usually have to connect them to some amplifier (a transistor etc.) before driving something low-impedance like a LED or a speaker.

 

[fbchurch2009]

so all i need is a transistor and I should be good? anything else? This is just for experimenting so I don't really know too much about this....

 

[Resqueline]

You might get away with just one transistor & two resistors.
There is a piezo sound-to-light circuit 3/4ths down this page.
http://www.talkingelectronics.com.au/projects/200TrCcts/200TrCcts.html

 

[HammerSlammer]

You might get away with just one transistor & two resistors.
There is a piezo sound-to-light circuit 3/4ths down this page.
http://www.talkingelectronics.com.au/projects/200TrCcts/200TrCcts.html

The link took me to a page that talked about broadband connections; nothing else.

 

[(*steve*)]

This thread was from about 4 years ago. I think Colin's site has moved/changed since then.

I'll see if I can dig up what was on that page 4 years ago...

 

[(*steve*)]

I couldn't find the exact page, but something similar is here: http://www.talkingelectronics.com/projects/100 IC Circuits/1-100_IC-Ccts.html#2

With a little adaptation that might work for you. And it's simpler than I thought. (The 5 components on the far left are the core of it.) The design also means that no protection is required.

Let's continue this in the other thread...