http://arduino.cc/en/Tutorial/Knock
but with a speaker. im not using it for a knock sensor tho. i just want to play around with the tech. maybe measure some vibrations.
OR
like this
http://arduino.cc/en/Tutorial/tone
but with a speaker. im not using it for a knock sensor tho. i just want to play around with the tech. maybe measure some vibrations.
OR
like this
http://arduino.cc/en/Tutorial/tone