TOD controller - knob, wheel, or buttons?

[AREA 51]

When you said knob, I figured it was the same as a fixed position rotary switch. As far as the torque splits I'd like to see the following percentages to the front : 0%---15%---50%. Anything in between and you're just slipping the clutches in the tod, right? The 15 & 50 are factory figures and should be safe for the tod, although I'm curious about the tod clutch slippage at 15%.

I'll most likely buy one whatever the splits end up being.

Thanks

[LiquidVX]

I wish for buttons. But it seems I am out numbered.

[mbeach]

I wish for buttons. But it seems I am out numbered.

Buttons aren't a far jump from a knob. The knob just integrates all of the buttons into one fixture.

The TOD's e-clutch slips itself. It's kinda hard to explain without going full nerd. Each "cycle" or period lasts for 20 milliseconds. If the E-clutch were operating at a 50% duty cycle, the clutch would be engaged for 10 milliseconds, then disengaged for 10 milliseconds, then engaged, etc...

Since this is a coil, it takes a millisecond or so to really "load up" when current is applied. To operate at 100% duty cycle would burn out this coil over time. There would be no "rest period". In 4hi, the coil is working at @90% duty cycle, this is the same as 18 milliseconds on, 2 milliseconds off, 18 on, etc...
Even at idle, there is a brief surge of current every 20 milliseconds. So, in "2wd," there is a little bit of e-clutch engagement.

My first circuit went wild with the higher duty cycle. After 24 hours or so (this will never really happen in real life), the frequency shot up in relationship to the duty cycle. In short, at higher duty cycles, the 20 millisecond period went up to almost 10 milliseconds. This means that the clutch was being pulsed 2 times as fast as it was designed to be. This is bad. I'm bench testing another design that I found on the web. It'll probably work because a.) it's simpler, and b.) I didn't design it (I'm a mechanical engineer, I shouldn't be fooling around with electricity).

I have no intention of building these things "ready to install." Frankly, my time has a cost, and if I were to spend 2 hours putting it all together, we would suddenly crack the $$ barrier. Figure in the components (still less than $10-15) and shipping and it becomes unreasonable.

I'd like to provide the schematics, as well as a PCB (printed circuit board) layout. I could even burn the PCBs here if there's enough interest. Each person would be responsible for finding the components (if it can't be bought at Radio Shack, I'm not using it), and assembling the controller. There will be some soldering involved. I'll be able to provide some nice pictures of the finished board so component assembly will go smoothly.
This should be no more complicated than those electronic kits that you can buy for your kids (like the DIY lie-detector or the DIY burglar alarm).
The real difficult parts were getting the data together and determining what duty cycle corresponds to what torque split. Now that that's done, it's just a matter of putting all of the pieces together.

[LiquidVX]

Thats awesome. Sign me up.

[sature]

thanks for putting so much time into this!!! you are awesome!!!

[BigDave]

Hi,
Great work ! I'll be in for 1 of what ever you come up with. I'd go for using the vacant switches giving the options of the existing auto, 15/85, 30/70, 50/50. Nice and simple.

I tried my JDM out in the snow a couple of weeks ago and can testify to the understeer. Overall, if I had the choice, I'd go for an ordinary old 4WD and a big toe on the brake where necessary.

Cheers........

[crager34]

This is going to be a sweet MOD. I want in when it's complete.

[Knigh7s]

Hey Mbeach,

Just wondering how this project is coming along? I could really use one with my manual hubs from Spazz.

Peer Pressure, Peer Pressure, Peer Pressure

Just kidding. Hehe

[Knigh7s]

^ Wut he said ^ ooh wait that was me?

[circmand]

But with a cover like in an attack plane to prevent accidental changing