Need Help Amplifying Voltage/Signal

[LiquidOrb24]

Hello,

I have been plagued for the last couple of days on how I would be able to amplify the voltage from an Piezoelectric buzzer or an electric drum pad so that when it is struck an array of LED's will light up.

I tried op-amps (but not sure If I had it set up right), transistors, and an audio amplifier but neither seem to work...I feel as if I built and rebuilt every circuit you can build to do this.

I don't know if I'm missing something with these circuits of just am building the wrong kind

Please if anyone can help me with a schematic that will take the input signal voltage with a peak between 200mV to 1.7V and amplify it to a voltage that would be able to drive an array of 4 LED's (Shown Below) I would be extremely grateful.

Or if not just a direction as to what IC I can use such as an op-amp or audio amp that would do the thing I want.

 

[ericgibbs]

ho lo24,
Post a sketch of how you how you have the PZ device connected to the
amp. Also any data you may have PZ.

Like to help, but as 'Johnny 5' says, 'need input'

Regards
EricG

 

[LiquidOrb24]

Heres the only circuit schematic that seemed to work for me to where when I hit the drum pad the lights do light up. However it seems like there is a simpler circuit out there that would do the same...

I took this one (Pic1 which is what I'm trying to go for) from audioguru's sound intensity indicator circuit but It seems to only work when I take it from the output of the first stage where the gain is about 101. I would like to take it from the second stage so I can put a filter on it and turn it into a square wave but whenever I try to do that after the first stage it messes up the rest of the circuit and the lights don't work anymore.

Some simpler ones I built but don't work are shown after the circuit below (where the electret microphone will be replaced with the drum pad.

Please if anyone knows how I can simplify the circuit so that there is one stage of an op-amp I would greatly value your help.

 

[audioguru]

My previous circuits respond to long music notes. It would light an LED only very briefly when a drum pad is hit and the LED won't be seen.

Here is another circuit that lights an LED but it has a capacitor to stretch the pulse long enough for you to see it. It would show a drum beat very well. Replace the pot with a biased electret microphone and add a capacitor between pin 1 and pin 8 to boost the gain if you want.

A piezo transducer might need its polarity turned around to work better. Remove the volume control pot when a piezo transducer is used.
A lighter has a piezo that is hit with a small hammer and it makes a few thousand volts. I hope your transducer doesn't break the input of the LM386.

 

[LiquidOrb24]

Wow thank you Audioguru...Once again you saved my ass. I haven't built it yet but I plan on doing that later today. Thanks again and I hope it works.

 

[sstimuluss]

hey i'm not sure what you're using the electric pads for, but i've been messing around with a custom midi interface a bit, and to trigger midi notes, i've just been lazy and hacked into a small old midi keyboard (evolution mk-125)...
but i'm assuming you could do it with any midi keyboard.. if you find the switch terminals under the keys, and connect those to a 4016 bilateral switch, you can then trigger the notes with pretty much any circuit..
so if you replace/put in line with that LED in audioguru's circuit with a 4n25 optoisolator, and then use that to close the switch on the 4016, you could trigger midi notes with your drum pads..
this is just the basic idea though, probably need to filter out glitch notes...if you're interested let me know