VSS Filter logic.

[tobmag]

Lance.

This is just fun for me and Im also learning a lot at the same time.
Ive been thinking the same as welll, an engine will see a much higher "lowest" hz compared to the transmission.
My engine ECU with a 36-1 trigger wheel will see about 450hz at idle

Then adding a tremendous amount of different trigger wheels with different teeth number, tooth width, diameter, gap between sensor and wheel. Different vr sensor etc each item adding a new parameter.

Francly I dont really think that we can build a circuit that will work 100% for all possible variations, but we can get very close

I will test the max9926 circuit first since that is a ready solution and I now have it here on my desk.

Br//Tobmag

[ashford]

the 1124 circuit i use is extemely simple it uses only 6 pins on the 8 pin ic and works well with both my 4r70w(6 hole vr) and 4l80. i can post up a pic of it if necessary

[Bernard Fife]

ashford,

Yes, please post it. It may be possible to designed a small board that gives a number of 'known-good' build options, including the 1124 and 2907.

Oh, I meant to send some condolences to Tobmag for the coming snow! I once lived in Ottawa, and ice racing (20+ cars on a track plowed into a frozen lake) was the only thing that got me through the winter. It's much warmer where I live now (but still Canada, so not exactly tropical!).

Lance.

[ashford]

this is what i used on the 4l80 the 4r70 was the same except the capacitor was a .02uf
http://www.onsemi.com/pub_link/Collater ... 0SHEET.PDF

ncv1124.png (14.17 KiB) Viewed 15898 times

[Bernard Fife]

Great, thanks for that!

[tobmag]

Ashford.

That is a very simple install, unfortunatly that particular circuit is very difficult to find here in Sweden even in Europe...
For sure you can get it from Ebay I guess, DigiKey and others do have them but then you spend USD1 for the circuit and USD100 on freight...

I assume you still need to do some trimming on the resistor at pin 1?
I'm also very afraid of using capacitors on the input circuit (VR input) since they are a source of possible self oscillations(that is what happend with my 555 Schmitt trigger)
As I understand you will also need to trim the capacitor value?

Otherwise its a super simple circuit possible for most home electricians to build.

Can you post any log, would be very interesting to see how your OS signal looks.


BR//Tobmag

[tobmag]

Oh, I meant to send some condolences to Tobmag for the coming snow! I once lived in Ottawa, and ice racing (20+ cars on a track plowed into a frozen lake) was the only thing that got me through the winter. It's much warmer where I live now (but still Canada, so not exactly tropical!).

This is very popular in Sweden as well but most of the racing is on a elegal basis, last winter we had a leathal accident so the police is watching this very closely now...

For the ones that dont have snow and ice this is what we are talking about, in this movie just some amatures out having fun (jump in to about 3,5min for some onboard cameras);
http://www.youtube.com/watch?v=7FU56OpvywQ


BR//Tobmag

[ashford]

Ashford.

That is a very simple install, unfortunatly that particular circuit is very difficult to find here in Sweden even in Europe...
For sure you can get it from Ebay I guess, DigiKey and others do have them but then you spend USD1 for the circuit and USD100 on freight...

I assume you still need to do some trimming on the resistor at pin 1?
I'm also very afraid of using capacitors on the input circuit (VR input) since they are a source of possible self oscillations(that is what happend with my 555 Schmitt trigger)
As I understand you will also need to trim the capacitor value?

Otherwise its a super simple circuit possible for most home electricians to build.

Can you post any log, would be very interesting to see how your OS signal looks.


BR//Tobmag

the capacitor is optional as a low pass filter, i did the calculations for about 150mph. the variable resistor is suposed to be the same as Rsensor +R1 since i didn't have a 12k ohm resistor i used a variable, it also seems to have an affect on hysteresis.

i looked and coul'd not find old before logs but have a few after logs, basically the speed would slowly rise by itself when stopped and jitter all over the place when actual speed was below 30mph.

[Bernard Fife]

DigiKey and others do have them but then you spend USD1 for the circuit and USD100 on freight...

Tobmag,

For those that want them, I can pick up a bunch of NCV1124 ICs (NCV1124DR2GOSCT-ND) and drop these in envelopes for those that want them. The IC is under $3, and in an envelop I expect that shipping would be under $2. So I would probably be able to ship these out for about $5 to those that want to try this.

This are SMD chips, but the pin spacing is 1.27mm, so it's not too bad for soldering.

Before too long I hope to have a small PCB to go along with this, maybe with the chip already soldered on, which should make it really simple.

BTW, the LM2907 ( LM2907N-8/NOPB-ND, http://www.digikey.ca/product-detail/en ... PB-ND/8310) is just $2.15, and I could ship these too, if there was sufficient interest.

Lance.

[tobmag]

Lance.

If you are willing to send a chip over I could test it on my bench/in my car for sure.

Thinking a bit ahead here as you rember I had the exact same issue with the mirtotcu with the max9926.
I assume its using the same surrounding components as the mircosquirt so its possible it should be revised as well.

The LM2907 is much easier to find, I have a handfull laying here.

Br//Tobmag