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[Keith]

I have an an idea, probably crazy, that it might be useful to have a push button that delivers a torque pulse on demand, much like a clutch can do when quickly engaged. Sometimes this is useful off road to wheelie over a log or do a flip turn. Twisting the throttle can be too slow to deliver the surge and too slow to go back to a more reasonable position.

I think this would be fairly easy to design with some simple electronics. Of course there is some danger in modifying the throttle signal but still...

So what if there was a button like a kill switch on the left side that gave a burst of power when pressed? Maybe with adjustments for the amount and duration of the pulse using a one shot circuit. And maybe a delay to prevent unwanted multiple pulses from happening. And some careful design to avoid any stray triggering, danger, danger!

Does anyone think this idea would be worth pursuing? I really don't miss the clutch except for this purpose. There are a few ways it could be done. Press to trigger a power pulse, press and hold to coast with pulse on release, press longer for a bigger pulse, combine with throttle twist to vary the pulse power. Who knows what's best, this is uncharted territory, or is it? Lots of crashing during R&D  . Looking for comments...

[Shadow]

Having seen what happens when a person loops an FX... without any mods... don't you want more control than a push-button?

[BrianTRice@gmail.com]

Inherent risks aside...

You could have the button press trigger a fast ramp up of the throttle analog signal to the maximum and then ramp down on release. And definitely debounce it more than a second or so to avoid accidents.

A small board like an Arduino could accomplish this, but it would need just the right analog output and varistor (or other component) to modify in series with the throttle, and it'd need to be powered from the Sevcon.

I don't believe that you can override the torque/current limit, though, even momentarily.

Now, the risks are probably: belt stress and possibly snapping, traction loss, design that makes failure increase torque to maximum rather than fail low, and basic connection failures and environmental damage.

[Keith]

Maybe the loop is because of the too slow response of the throttle twist. A pulse would be off instantly, in theory. And a real clutch will disengage quickly too.

I don't think the desired torque would be more than maximum, but more research is needed. Adding a pulse to the existing throttle signal would make it variable, twist plus pulse, so even a half max pulse might be useful.

The insane wheel spin that occurs after a big throttle twist and traction loss might be reduced by a quickly ended pulse. Maybe even followed by a regen pulse to counter the wheel inertia. So many variables.

[BrianTRice@gmail.com]

Wouldn't changing the value of torque too quickly in either direction directly impact the belt? Some Buell owners would probably know...

[Keith]

Well I wouldn't know, I run a chain.

With an Arduino and a signal from the abs, it might be possible to terminate the pulse whenever wheelspin or some reasonable rolling speed is detected. I was thinking of a simple analog design.

A lever rather than a button could certainly be more like a real clutch, but seeing all the trouble people have with variable regen levers and transducers etc., it might not be worth it.

[Keith]

So the Arduino 101 has a 6 axis accelerometer that could prevent looping out and with BLE you could dial in your settings from a phone. Maybe even get a self driving wheelie mode, just hold the button down! Now how much would you pay?

[Keith]

So here's what the wiring looks like for the 2016 Bitron throttle. Appears to have two separate control outputs. I have not been able to trick it into spinning the motor on a stand, yet. It is not simple like the earlier three wire pot. Measured voltages are 0.5 to 4.5 on brown, 4.5 to 0.5 on brown/red, no twist to full twist. So differential, out of phase, balanced, whatever you want to call it. http://www.freepatentsonline.com/8278912.pdf

[BrianTRice@gmail.com]

Nice! Here's a little writeup on the unofficial manual now:
http://zeromanual.com/index.php/Unofficial_Service_Manual#Bitron_Throttle

I think that arrangement is just a voltage divider, but I could be wrong.

[BrianTRice@gmail.com]

So the Arduino 101 has a 6 axis accelerometer that could prevent looping out and with BLE you could dial in your settings from a phone. Maybe even get a self driving wheelie mode, just hold the button down! Now how much would you pay?

That is attractive: https://www.arduino.cc/en/Main/ArduinoBoard101

A 6-axis accelerometer won't do much for wheel spin-up, but would prevent a wheelie, I suppose.

What would I pay? Well, it's not exactly the feature-set I want, but someone who wanted the performance kick should probably be prepared to pay $200, I'd guess, if it had a solid build quality and were easy to install. If it were just a DIY kit, maybe $100?

This would be relatively warranty-risking kit, for sure, though, so DIY is probably a reasonable angle with available source code to customize.

FWIW, my ideal kit is a way to use a five-button controller for things like a reverse torque mode, an increased regen mode, and a few other bells and whistles that an Arduino could easily manage. But for what I want, it's the wiring to the OBD serial lines and the Sevcon pin inserts that are worth having a kit for.

[MrDude_1]

A proper feeling "clutch lever" would be an amazingly useful mod.
However a button just sounds like you're asking for trouble.  As someone that clutches up literbikes and open class two strokes, I can promise you that even when it seems like everything is happening really fast, it is NOT a slam on/off like a button. Even fast clutchups have a feed and feel to them.

[Keith]

A button may or may not be useful, but it is pretty simple to try. The response will be softened somewhat by the controller and inertia. I'm thinking just push to force the throttle signal to off, then release the button to quickly unleash however much twist you want. Too much? Push it again. And custom regen might be useful to balance against the acceleration. I'll have to try it now that I know how to connect it. The digital line on pin 8 is probably a wire off detection. That would be easiest to switch, but it probably triggers an error response with possibly a slow recovery. So a DPDT switch to interrupt the throttle signal would do it but takes 6 wires to the switch or a relay. And going to 0V and 5V might also trigger an error so more parts to match the untwisted voltages.

Getting an electronic clutch lever would be a major project starting with the electromechanical lever itself which would be very different from the brake regen levers that have been done. Then it would need signal processing to modulate the throttle, probably Arduino level complexity. The torque of the Zero is much less dependent on rpm than an ICE bike, so the behavior would not be the same. Maybe the clutch feel is not necessary, only experimentation will tell.

I'm tempted to play with the 101 Arduino but it would consume a lot of time, maybe during the winter months. Thanks to Brian for the wiki update, I had that in mind when I made the schematic.