Originally posted by bnoon:
How far along are you on cracking things with TwEECer anyway? Gotta tell you, I hated writing my own code to expand some resolution on one of my maps... I'd hate to be the one trying to crack things...


I can program just about everything that "should" be "played" with.

I can program several things that really "should not" be "played" with.

I have a few things I can change (easily that is) but that I still don't have any "real" information on as of yet.

I can program all the transmission functions. Too bad I don't have a slushbox. Well NOT really too bad I guess...

I had not looked more into it for a while until my IMRC died a month or so ago. They I had no choice but to get off my duff or spend $100+ on something I wasn't using anyway. It was a hard choice...


I have the rpm converter circuit designed and laid out.
Matter of fact that's my plans for tonight to start soldering everything together and testing the circuits.

As I normally do I think I over engineered it but then again it's built in such a way that there will never be any input voltage deviation, beyond minimum ripple, & incredible output resolution. (It has a built in voltage doubler and regulator so input voltage is fixed and above the minimum needed for the opamps to stay accurate. )

The higher the rpm (Hz input) the more accurate the circuit.
For instance it has a +/- 30 rpm deviation at 4000 rpm.
At 8000 rpm it's only +/- 12 rpm. (4.86v on a 5v capped scale)

I used that as the top of the scale to maximize resolution per Hz. (That formula was the easy one - the V ripple verses C2 was a freakin' PITA! )


For reference the LM-1 unit is quite accurate itself and has minimum deviation of + or - 50 rpm. (100rpm total) However their's gets worse the higher the rpm. (for instance their minimum deviation at 8k rpm is +/- 80rpm)
They trade off less resolution and response time for self learning rpm scaling (very cool from a business standpoint!!! Love to see that circuit) and a higher rpm scale.
In the grand scheme even that minimum 160rpm total deviation is not much really. Though I don't think they factored in voltage ripple. That looks like just the deviation of their chip and circuit.

Also my version cost about $30 total and I can build 2 cables plus enough IC's and misc stuff left over to build 3 rpm switches of any kind.
($60-80 for an MSD switch - What mark up! )


I do feel like I've had a years worth of EE classes compiled into 1 month though...

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.