Hi, total noob here so be gentle. I have a project to power LEDs via Arduino to react to a sound input using s sound sensor. Fortunately most of the information I'm looking for already exists. Me question is about the sensor itself.
If I use a KY-037 Sound Detection Sensor with the integrated piezo microphone, can I simply remove the microphone, split the signal from a piezo instrument pickup (simple piezo pickup) and thus make the sound input signal based on the pickup and not a microphone that would pick up ambient noise?
I also have the option of a post preamp signal.
This may be spoken to elsewhere, I'm still looking. If you can point me to something of this nature or speak to this yourself, I would much appreciate.
Please explain what you are trying to accomplish. The sentence you gave us needs to be "fleshed out" with some details about input constraints, what the microphone will be attached to, what kind of signal it should detect, what kind of reaction is desired and so on. It will be more productive than trying to explain how to modify a sensor module, because it is probably not the best way to do it.
I don't have the schematic but the input impedance of the preamp is probably too low for a piezo pickup (or a regular guitar pickup). The low impedance will "kill" the signal.
Before you do anything too complicated make build the little audio input circuit at the bottom of this post. Except use 1M or 10M resistors (and you can use a lower value capacitor). Then run the Analog Read Serial Example to see if you're getting usable readings. If not, it should give give you enough signal to get an idea of how much gain you need. (You can take the delay out of the Analog Read Serial Example to better "catch" the peaks.
I found a piezo preamp schematic. It "looks reasonable" to me. The Arduino input still has to be biased. You can use the circuit above or build the bias into the preamp. That preamp is biased at half the supply voltage, and then the bias is removed with C4, so if you run it at 5V at leave out C4 and the output pot it should be good. But, you'll probably want a "rail-to-rail" op-amp to have the full 0-5V swing available.
The gain is determined by the ratio of R5 & R3. That's standard op-amp theory so you can do some research if you need to adjust the gain.