I just use a 9V battery. Amp module is in one side and battery in the other. So I have no vehicle connections at all - just run the mic under the bonnet and go. Keeps it nice and portable because as you have probably found out - once you know how to tune everybody wants you to do their car!!
PL
Knock Detection systems
Moderator: Matt
Thanks for the reply! So I am going to build up a solution with earphones. I think your arguments are substantive. I will look around if I can get a little headphone-amplifier here in germany that works like yours (as I am sure that this will be much easier than finding an old cassette player with all ports that @Legionnaire one has 
).
By one thing I am afraid: To learn how knock really sounds I must force the engine to knock (at least a little bit).
Do you have a part number of a knock sensor that works well with a SR20DET?
).By one thing I am afraid: To learn how knock really sounds I must force the engine to knock (at least a little bit).
Do you have a part number of a knock sensor that works well with a SR20DET?
Another thing I was considering is using the "in ear" type "ear phones". Some of these seal into your ears really well - blocking out all external noise. Like these:
http://store.shure.com/store/shure/en_U ... .105432000
The only downside is that you can't build the electronics into them and it'd be a pain fitting/removing them all the time if you wanted to talk to other people etc. while tuning. Just a thought....
If you're afraid of making your engine knock then try it on an NA engine first. Just dial in lots of IGN timing and go driving. Take it easy though. Once you're familiar with the sound you'll pick it quite easily.
Or you can dial in lots of timing in the boost transition area of an SR20DET - this avoids making it detonate at full boost. 30 to 35 degrees at 3000 - 3500 rpm should do it. It's easy to hear at this point cos the engine isn't making a lot of mechanical noise. Tread lightly though - you don't wanna break your precious SR!
PL
http://store.shure.com/store/shure/en_U ... .105432000
The only downside is that you can't build the electronics into them and it'd be a pain fitting/removing them all the time if you wanted to talk to other people etc. while tuning. Just a thought....
If you're afraid of making your engine knock then try it on an NA engine first. Just dial in lots of IGN timing and go driving. Take it easy though. Once you're familiar with the sound you'll pick it quite easily.
Or you can dial in lots of timing in the boost transition area of an SR20DET - this avoids making it detonate at full boost. 30 to 35 degrees at 3000 - 3500 rpm should do it. It's easy to hear at this point cos the engine isn't making a lot of mechanical noise. Tread lightly though - you don't wanna break your precious SR!
PL
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Legionnaire
- Posts: 125
- Joined: Fri Oct 03, 2008 5:45 am
- Location: Moscow, CFD, Russia
When I decided to make up a knock detector like this, I started to look for an amplifier, just like PL suggested. I then used a player purely because I found one in my garage and because it has an entirely suitable amplifier and a nice bonus on a form of all necessary sockets built into it so it looks tidy when complete. I'm 100% certain that your local electronics shop has plenty of different amplifiers in DIY section. Those usually cost about 5-10 euro. You then can buy (or make yourself) a suitable body and mount all the sockets you want in there. I just shared my version of KDK. A similar electronic one has been described on autospeed website.
If you do not like the whole idea of using electronic components ('cuase for example I myself am not really into all these soldering affairs, so I asked my friend to help me with it), you may be better off with det cans. I dont have first hand experience with them but those who do report that it works very well. To illustrate the point, here are some quotes.
From PL:
A step by step guide can be foun here (pic intensive):
http://forums.neons.org/viewtopic.php?t ... hlight=det
If you do not like the whole idea of using electronic components ('cuase for example I myself am not really into all these soldering affairs, so I asked my friend to help me with it), you may be better off with det cans. I dont have first hand experience with them but those who do report that it works very well. To illustrate the point, here are some quotes.
From PL:
from a guy from another board:I've found that I can hear knock very easily at low to mid rpm when doing road tuning even without any form of det cans as long as the car is quiet inside. At high RPM you're much better off with det cans though.
And lots of positive feedback from honda folks.A rather bizzarre and very cheap method is to run some relativly solid plastic tubing onto the engine ( like onto the end of a stud) and the other end goes into the cabin / outside the test cell and is attached to a large open ended tin can with a pipe soldered to the bottom to fix to the other end of the pipe. The pipe is drilled through to give a hole into the pipe from the can base You can then hear det usually as a sharp crackling noise.
We used this at Cosworth a couple of times would you believe
Matt
A step by step guide can be foun here (pic intensive):
http://forums.neons.org/viewtopic.php?t ... hlight=det
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skylinegtrhr
- Posts: 301
- Joined: Sat Jun 21, 2008 1:50 am
- Location: Croatia
- Contact:
Yep. I've got that very unit. Somewhere.
Downsides were that the little cheap headphones don't keep external noise out and using the "clip the mic to the engine" technique results in hearing a lot of mechanical noise.
Be easy to upgrade though - by insulating the mic from the engine (as I described previously) and adding a set of quality headphones - or even "in ear" sealed earphones like the Shure type.
PL
Downsides were that the little cheap headphones don't keep external noise out and using the "clip the mic to the engine" technique results in hearing a lot of mechanical noise.
Be easy to upgrade though - by insulating the mic from the engine (as I described previously) and adding a set of quality headphones - or even "in ear" sealed earphones like the Shure type.
PL
So today I have built a rudimentary solution based on the informations from @legionnaire:
- A friend of me has give me an original Nissan Knocksensor with a connection plug.
- Another friend has give me a Sony TCM-59V cassette player with mic input (the world is small...
).
- a 3,5mm jack extension cord from my cellar.
- a pair of Earphones (I have already a few for testing purposes).
I soldered the knock sensor to the extension cord and simply plug it into the mic input from the cassette player. No modifikations where made on the cassette player.
My first results:
If I press "rec" on the cassette player (with parallel bridging the rec-lock on the cassette player) I hear sounds from the knock-sensor. The test with the water pipe in the bathroom runs fine! I can hear the water streaming but there were a lot noise floor from the cassette player in the background.
So I looked around if I can connect the knock-sensor to the laptop.
I found a program that be up to the mark: Audacity is an open source project with the ability to record sounds with parallel playing it. So with Audacity I am able to record the sound from the knock-sensor and hear it parallel on the headphones.
One more benefit with Audacity: Audacity plays the mono-signal from the knock-sensor on the left and the right earpeaces (I hope this is the right term...) from the earphones. When I am using the cassette player I can only hear the noise from the knock-sensor on the left side from the earphones.
The noise floor with connection to the laptop is much less than with the cassette-player.
There you can download Audacity if you want to test it too:
http://audacity.sourceforge.net/?lang=en
I used the version 1.3.6 (Beta).
Now I have to test it directly on the car itself.
- A friend of me has give me an original Nissan Knocksensor with a connection plug.
- Another friend has give me a Sony TCM-59V cassette player with mic input (the world is small...
).- a 3,5mm jack extension cord from my cellar.
- a pair of Earphones (I have already a few for testing purposes).
I soldered the knock sensor to the extension cord and simply plug it into the mic input from the cassette player. No modifikations where made on the cassette player.
My first results:
If I press "rec" on the cassette player (with parallel bridging the rec-lock on the cassette player) I hear sounds from the knock-sensor. The test with the water pipe in the bathroom runs fine! I can hear the water streaming but there were a lot noise floor from the cassette player in the background.
So I looked around if I can connect the knock-sensor to the laptop.
I found a program that be up to the mark: Audacity is an open source project with the ability to record sounds with parallel playing it. So with Audacity I am able to record the sound from the knock-sensor and hear it parallel on the headphones.
One more benefit with Audacity: Audacity plays the mono-signal from the knock-sensor on the left and the right earpeaces (I hope this is the right term...) from the earphones. When I am using the cassette player I can only hear the noise from the knock-sensor on the left side from the earphones.
The noise floor with connection to the laptop is much less than with the cassette-player.
There you can download Audacity if you want to test it too:
http://audacity.sourceforge.net/?lang=en
I used the version 1.3.6 (Beta).
Now I have to test it directly on the car itself.
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The results are better than we had? 
Are the headset amplifier too insensitive?
But for first time we had good results
I'm also involved in the knock-detection interested, but maybe we can use the stock knock-detection for the RB26DETT. I think the knock-detection system are certainly better.
There are no nasty noises from the poor engine, crap chain-timing and rocker-valve
Are the headset amplifier too insensitive?
But for first time we had good results
I'm also involved in the knock-detection interested, but maybe we can use the stock knock-detection for the RB26DETT. I think the knock-detection system are certainly better.
There are no nasty noises from the poor engine, crap chain-timing and rocker-valve
Yes the results with the cassette player (and with the notebook and Audacity too) are quite better (and louder) than the first experiments with the mic-preamp solution plugged into the pc. I think the mic-preamp circuit is build for another type of microphone than the knock-sensor.Fuzzy wrote:The results are better than we had?
Are the headset amplifier too insensitive?
Now I must search if I can apply a filter or equalizer during the recording in realtime for the right frequencies where knock is mostly.
Nissan S14a (SR20DET) :-)
Just an update:
The solution works pretty good. The most difficult thing is to find a good place for the knock sensor without having too much noise from the head. For my test drive I bolt the sensor onto the intake.
Sample Sound: Engine_Sound_S14a_SR20DET_Test1.zip
The solution works pretty good. The most difficult thing is to find a good place for the knock sensor without having too much noise from the head. For my test drive I bolt the sensor onto the intake.
Sample Sound: Engine_Sound_S14a_SR20DET_Test1.zip