Over in this thread:
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=30641
it was announced that the NuVinci N171 developers' kit, which I have wished to have for years, was going for cheap ($150+shipping!). I still have no budget for it, but a fellow ES member, GlennM, offered (unasked!) to get one for me to help my projects along, and hopefully to expand the ES knowledgebase as I figure out ways to use it that might be a bit different from how others do things. :lol:
So the order was placed last week, and today mine arrived, and passed incoming inspection:
View attachment 4
and appears to have all the parts (I only glanced thru the list vs what's there):
View attachment 3
That shifter motor looks almost exactly like one I saw in a Japanese car in a junkyard, used for a window rollup motor. I think it's even the same company, but it's been a couple years so I'm not sure.
It *is* heavy, feels about the same as a Fusin gearmotor, and is roughly the same size (but narrower).
There's been some good discussion in the above linked thread about ways to use these, but until I had it here I woudln't be sure how it all could integrate in...I kinda need to hold and see things in person to really grasp what I might do with them.
Holding it in my hands, I can visualize how I will probably use it: Output from the NV to the rear wheel on the *left* side, via sprockets on the brake rotor mounts.
Input to the NV via one of two methods:
--Dual freewheels on the right side, if I can figure out a way to do it (possibly using a BB cup, modified, to extend the threading, if there's space)
--Single FW from the jackshaft Thud made me for CrazyBike2's original drivetrain, and pedals and motor will be combined via dual freewheels on the JS's left side, output on it's right.
I'd already planned essentially the last one when pondering using the SA 3speed IGH as a jackshaft at the pivot point of the rear swingframe, or near it, so the only real difference is the huge weight and size difference.
I may decide not to use any freewheel on the motor side of things, and only put one on the pedal input to the NV, to prevent backdriving them, since this bike really would suck to pedal anyway, most likely, given it's projected weight. :lol:
The electric-powered autoshifter setup can be controlled either by analog input 0-5V, or shift maps using up to 64 shift points, which will shift up or down automatically as specified by the user-programmable maps when wheel speed reaches one of those points.
You can even put a switch on the handlebars to switch between two maps on the fly.
But you can't switch between manual and automatic on the fly--you have to reprogram the shifter via USB from a PC to do that.
Seems like a feature anyone might want to test out, so it's odd that this isn't a core function. Oh, well. I'm used to that kind of thing.
I could in theory build an analog autoshifter mapper (with op-amps, and comparators and/or transistors) that would read wheel speed and shift at certain points (preset with pots rather than code), and still allow for manual override control of shifting. It would still use the normal autoshifter from the devkit, but in pure analog manual mode. Probably wouldn't even be that much work to design and build, but it's not something I have time for yet.
Another idea I had was to use the output to the shifter motor itself to disengage the traction motor's throttle momentarily, so that shifting can quickly happen without much load on the shifter motor. It'd be something like this:
If I decide to totally forgo the electronic autoshifting, I can also theoretically build a manual cable-operated shifter. It still works by turning the square rod, so as long as I can work out a manual control system that turns it, like a dual-cable (pull/pull) reel, with a 4:1 ratio or more at one end or the other, then it should be possible.
)
