did you ever get the knock sensor to work?

 

Yes,.. Sorry I didn't report before now. It works. Well I think it does. It is showing me a constant 2.50 volts plus or minus 0.10v. I think if I had knock that it would show peaks. Right now, it's pretty constant around 2.5v. It would be really nice if the Zeitronix software had upper and lower alarm limits.

Does anyone know what kind of values I would get with knock?

Later,

 

We can add limits fairly easy. All you need is an A/d converter and some custom software. Program is so that an output comes on below a preset value and above a preset value! Will the unit accept digital inputs?

 

No digital input on the Zeitronix but the user input can be datalogged from it's serial port using the included software. This can be addressed on the software side by writing some kind of digital guage software similar to HKS CAMP.

 

Does anyone know how the knock sensor works? I looked in the service manual and found that at normal operation it rests at 2.5vdc. But, when it detects knock does it go to 0vdc or 5vdc?

 

PM ... PHunk ,He should know . Or you can call J&S safegaurd .

Madelinot , Let us know if you can get this thing hooked up and working with the Zeitronix .

 

It is alerady hooked up and working. I can log the data if you wish to have a look at it... I am just not sure how the data is different if I experience knock.

Later,

 

Have you logged any of it ? Does the 2.5 volts change at all ?

 

The raw signal coming off the knock sensor is audio. Connect it to an amplified speaker, and you will hear your engine running, minus the exhaust note.

The sensor is basically an accelerometer, producing about 20 mv/g. If you look at it with a scope, you'll see maybe 0.5v peak to peak ac signal, with normal engine noise, and at least double that with knock.

The knock event lasts for just a millisecond or so, so you will need at least a peak detector (diode and cap) to sample the signal long enough for the data logger to get a look at it.

The knock freqency varies with cylinder bore diameter and combustion temperature, but it's usually between 5 to 10 kHz. Frequency filters are not the magic bullet everyone thinks they should be, so don't waste your time looking for the perfect bandpass filter.