Single-Speed Momentary Pushbutton Throttle?

Joined
Mar 8, 2016
Messages
29
Location
Valparaiso, IN, USA
Hello everyone,

I'm finishing up my 2nd ebike conversion, and want to do the throttle differently this time. I use a Cycle Analyst with cruise control feature, and I almost always just set the throttle to full for 2 seconds until cruise kicks in, and then let it go. I don't really need to use the throttle at any other setting - I just ride unassisted in any other situation.

Considering that the grip I have that is made to match the throttle isn't good for longer rides (my commute is nearly an hour each way), I'm going to use a more comfortable grip - think Ergon. The grips that came with the bike are actually similar to their GP1, so I want to try these first. And I'd rather not cut the grip. Something like this:

http://em3ev.com/store/index.php?route=product/product&path=41_57&product_id=144

would be ideal if it had just a momentary on/off button. Something small enough that I can just slide it on next to the full-length grip, taking up little space on the bar. Has anyone seen such a control anywhere? Or know if it's possible to modify the above one in such a manner (without damaging it)?

Thank you.
 
Ya - a horn button is perfect (search eBay).
Hook it from 'throttle +5V' to 'thottle signal'. Since you have a CA3 you can fiddle the ThrO->UpRate if necessary to keep things civil when you hit the button.

hornButton.png
You can always swap the rocker out on the switch in your link with a momentary rocker (these are pretty standard off-the-shelf parts) but it's not worth the trouble and expense. Just don't use a toggle like that directly to lock your throttle on. A horn button is much easier...

If you are always pedaling anyway, another thing you might consider is a PAS Wheel (since the CA3 supports it) and a CA 3-position switch to change presets. That way you would get configurable power (PAS->PASWatts) whenever you pedal and could switch it off by switching to a preset with no PAS (PAS->PASMode = PASOff) and/or no throttle (ThrI->CntrlMode = Off(0V)). See the Guide.
 
If you connect +5v to ground you will likely need a new controller. The +5v needs to be the signal seen on the sense wire. IIRC full throttle is about 4.5V so the full 5v will be fine.
 
Ya - what he said (well - new CA, not controller...) ^^^

pbtnThrottle.png

With this scheme the actual input voltage swing will be 0.00-4.99V which the CA will internally clamp to ThrI->MinUnput and ThrI->MaxInput, so the default or any other settings within the 0-5V operating range will work fine.

The input fault detection can be deactivated by setting it to any voltage equal to or less than ThrI->MaxInput. I might recommend 0.0V as a value that is strange enough to remind you that the feature has been intentionally disabled.

So, in short, reconfigure the Throttle In fault voltage setting to 0.00V to disable it and just leave your original ThrI Min/Max in place.
For instance:
  • ThrI->MinInput = 1.00
    ThrI->MaxInput = 4.00
    ThrI->FaultVolt = 0.00 (any value 0.00V to ThrI->MaxInput will disable the feature)
EDIT: updated with explanation and more reliable means to disable FaultVolt
 
I know I'm late here, but thanks, everyone! That horn button is exactly what I'm looking for. I was wondering whether it was momentary or toggle-type, but I think either would work just fine with my CA, since it locks in the setting after a set (programmable) amount of time.
 
Well, I've got the button, and I was able to get it to work. My only concern is that I can't set the throttle fault voltage higher than 4.99 V, and with the button pressed I get a 4.98 V input. Which means whenever I use the button I;m only .01 V away from faulting - way too close for my comfort.

Anyone know a way around this? Yeah, I could add a resistor to drop the voltage, but if there's a way to prevent faulting in software that would be preferred.
 
Your point is well taken.
The posted means to deactivate the input fault detection was not very good - sorry about that.

I've edited the post above with a proper method to disable the feature for this throttle setup.

  • FWIW: There was some mention above of using a normal switch for this instead of a momentary button. Very bad plan. Using the CA V3 cruise control as the OP describes is a nice solution that releases automatically on ebrake pull. Different amounts of fixed assist can be managed using an AuxInput pot or three position switch to dial in the current limiting. The beta 3.1 firmware also allows you to use up/down buttons to dial the AuxInput limit value if you like buttons instead of a pot.
 
No need to apologize! I certainly appreciate the help. After my last post, I decided to solder a resistor in series with the button. The throttle input impedance (between input and ground) on the CA was 110k-ohm, so I added a 5k-ohm resistor. This dropped the voltage input to 4.74 (as seen on the CA). I set the fault voltage halfway between that and 4.99, and this configuration has been working fine. In the process I cut away almost all of the excess throttle cable, and simply soldered the wiring and resistor together, then covered it all with heatshrink tubing.

The only problem I had was that the horn button was initially in the way of the front derailleur shifter, but I was able to adjust their positions. Ideally I'd have a 1X mechanical setup - I like the simplicity, including having just the throttle on the left side, and the rear derailleur shifter on the other side. But I'm just going to use the triple for now - it lets me experiment with what size of chainring would be ideal for a possible eventual conversion to 1X. So far, I normally use the large chainring - the middle is just a little too small. But I'm not yet sure the gearing on the large ring would be low enough should I need to pedal home without throttle.

The components are on the lower end, so they may not last very long.
 
Kevin Crawford said:
I know I'm late here, but thanks, everyone! That horn button is exactly what I'm looking for. I was wondering whether it was momentary or toggle-type, but I think either would work just fine with my CA, since it locks in the setting after a set (programmable) amount of time.

There's two versions of that button: One latches on and off, the other is momentary. The latching ones are sold as light switches am]nd the momentaty ones are sold as horn buttons.
 
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