TOD discussion

[mbeach]

Having the correct plug (we only need one of the two) would make life much easier, and it would look nicer.

As far as I can tell, we only need to cut/intercept 1 wire. The pink TOD to solenoid wire. We will want to 'tap in to' 4 more wires, each for the 3 display segments and one for the AUTO display.

That's 4 taps and one cut. Not too bad, even for a novice. We just have to make sure that everyone uses high-quality taps (if there really is such a thing). Vibration is the enemy of the wire tap (scotch-loc, et al.).

As for the 68% duty cycle for 4wd.
This is a bare minimum number, and at high speed may not be high enough.
The purpose here is not to replace the TOD's logic, we are just trying to modify its outputs. There really is no such thing as overkill as long as we provide a nice 50Hz pulsed signal to the e-clutch.
I say 87-88% duty cycle would work for just about everyone, regardless of battery juice available.

The biggest surprise for me was the presence of voltage at the pink wire when in '2wd'.

[VehiGAZ]

I think you're right - a decent margin above 68% will probably do the trick nicely - and if it's not enough to maintain full 4WD-Hi at 60 mph, well, you probably don't really need 4WD in that case anyway.

So, uh, are you going to throw a circuit together, mbeach? And post required parts and directions? Pretty please? Winter's coming here in Connecticut... :-)

[mbeach]

I'll try to work on this today. I have a lot of parts available to me that may not be readily accessable for most people.
Today I found a really nice trimmer that would make a cool knob. Very tactile with nice feedback. It felt like a BMW iDrive unit. It could be easily replaced with a 2k ohm potentiometer from Radio Shack though.
I'm trying to make it as simple as possible for everyone to build/commission to build.

Reality is, all we did here was to confirm the work that the Terracan guys did. I never was able to look at the links, but from Bob's first post, it sounds like we have just done our own version of the same thing.
I can't take any credit for this, but I assure you that a VX ready solution will be on the way asap.
I'd still like to share my spreadsheet, but I think that we can get started without it.

[mbeach]

It appears that there is a mass-produced PWM controller that will suit our needs. All we need now is a pot, a knob, and the ability to ground the indicator lights at will. This can be done through the same pot(entiometer) that selects the 4wd mode.

It's getting easier and cheaper by the day.

[Maugan_VX]

mbeach, if this works, and its simple enough for me to pull off in an afternoon's worth of work....


I'll fly out to Alaska and kiss you.

[mbeach]

Ha, I'll pass on the man-love -but thanks anyways.

Actually, when I stated looking back through old posts, it hit me that we (the board) were on to a solution a long time ago.
Especially in this post by SGT. Batguano:
"It may be a Pulse Width Modulated signal, like the speed signal, which is why no one has come up with a soultion to the top speed limiter of our ecu.

I may be wrong, but I've been under the impression that you can use a dc motor controller on a pwm circuit. So, I'm wondering if one could replace the rheostat or variable resistor on the dc controller board with a 4-position switch and four fixed value resistors."

And that's exactly what I've come around to. I found a DC motor/fan/lamp PWM controller that will work nicely, and only cost between $40 and $50.
That unit, a switch to activate MANUAL mode, and a rotary switch (no longer a potentiometer -long story) to select the modes and we are looking at a $75 mod, depending on how fancy you want to make it look.

I'm ordering a PWM controller from Critical Velocity today for testing.