I've been considering this just for peace of mind. Has anyone else built one? So far what I've seen it's mostly been the 4-cylinder/forced indution types that've done it. It appears it can be as simple as connecting a pair of headphones and it will be easier to hear (should you want to go that route). Another way (I may try this one) is simply to attach an amplifier to the sensor and hook up a speaker.
I don't know if I'm inclined enough yet to go this route, but I may build an audio level meter with a potentiometer to trim the actual input level.
Knock sensors are actually tuned to a specific frequency range. I found a formula to figure this.
Detonation frequency = 900 / 3.14 * cylinder radius (in meters)
So for a 350 (4" bore), 900 / 3.14 * 0.0508m = 5642Hz. You would need to build a bandpass filter for this (I think 5000-6000Hz should be sufficient).
I don't know if I'm inclined enough yet to go this route, but I may build an audio level meter with a potentiometer to trim the actual input level.
Knock sensors are actually tuned to a specific frequency range. I found a formula to figure this.
Detonation frequency = 900 / 3.14 * cylinder radius (in meters)
So for a 350 (4" bore), 900 / 3.14 * 0.0508m = 5642Hz. You would need to build a bandpass filter for this (I think 5000-6000Hz should be sufficient).
