Adding a Rotary Dial Speed Control

[6zfshdb]

Nice build! The LED's are a nice touch.

From a purely electrical perspective, there should be no reason why you couldn't use a 2 pole switch and common ground. However, when I tried it during my experiments, the throttle behavior became erratic. I can only guess but it appears there are eddy currents involved which affected the hall effect sensor. Isolating the ground return solved the problem. This may only happen with my particular bike/controller combination though, and a 2 pole switch may work fine on other bikes.

It's true that miniature 3 pole switches can be hard to find but they are only pennies more than a 2 pole. I found these on Amazon:

https://www.amazon.com/gp/product/B07VHC9LYG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

At $2.50 US each, I thought the price reasonable. I only needed 4 to convert my bikes though. If I were building a large quantity, the price would be more of a consideration.

Welcome to the forum and please post more pics of the finished product!

 

[PCeBiker]

Parts list:

1 K ohm potentiometer: https://www.amazon.com/gp/product/B074KGJ7N6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I did a lot of throttle experiments with different throttles and potentiometers and found these 1 k ohm potentiometers,..

The bottom one should be exactly the same as @6zfshdb 's potentiometer except possibly the physical dimensions.

The first potentiometer is sold as a "motor controller potentiometer" and is designed more for industry.
The knob design is easier to operate with the side of my thumb, and the movement has a really smooth heavy feel to it.
I can adjust it without moving the rest of my hand on the grip,..
It's a lot harder to bump it by accident,..

https://a.aliexpress.com/_mNFyhVh

It has screw mounts for the wires so no soldering.
I decided to fill it with dielectric grease, then seal it up with silicone, so it should still work if I find myself in a creek.




BUT, It has the same problem as all the other potentiometers and throttles I've dealt with for my ebikes, in that it has very little movement from no throttle to full throttle.

It was still hard to adjust the speed when it goes from zero to maximum in about ⅛ to ¼ of a a rotation.

But, I found this mult-turn 1k ohm potentiometer,..

https://a.aliexpress.com/_mMALO4T

I never did buy it and try it, but it looks like it might work Perfectly !!??

It's got 3600° of rotation, so the "active throttle movement" should expand from ⅛-¼ rotation to around 1 full rotation for the active throttle range ??

@6zfshdb I will buy one and have it shipped to you if you do the experiment.
I've got too many projects on the go and have to try and get my ebike ready for spring riding.

 

[6zfshdb]

I did a lot of throttle experiments with different throttles and potentiometers and found these 1 k ohm potentiometers,..


View attachment 189631


The bottom one should be exactly the same as @6zfshdb 's potentiometer except possibly the physical dimensions.

The first potentiometer is sold as a "motor controller potentiometer" and is designed more for industry.
The knob design is easier to operate with the side of my thumb, and the movement has a really smooth heavy feel to it.
I can adjust it without moving the rest of my hand on the grip,..
It's a lot harder to bump it by accident,..

View attachment 189632

https://a.aliexpress.com/_mNFyhVh

View attachment 189633View attachment 189634View attachment 189635


It has screw mounts for the wires so no soldering.
I decided to fill it with dielectric grease, then seal it up with silicone, so it should still work if I find myself in a creek.




BUT, It has the same problem as all the other potentiometers and throttles I've dealt with for my ebikes, in that it has very little movement from no throttle to full throttle.

It was still hard to adjust the speed when it goes from zero to maximum in about ⅛ to ¼ of a a rotation.

But, I found this mult-turn 1k ohm potentiometer,..

View attachment 189636View attachment 189637

https://a.aliexpress.com/_mMALO4T

I never did buy it and try it, but it looks might it might work Perfectly !!??

It's got 3600° of rotation, so the "active throttle movement" should expand from ⅛-¼ rotation to around 1 full rotation for the active throttle range ??

@6zfshdb I will buy one and have it shipped to you if you do the experiment.
I've got too many projects on the go and have to try and get my ebike ready for spring riding.

I did a lot of experimenting as well. The trick was to find a miniature pot that would fit in a small case, mountable so the switch & pot could be thumb controlled.

I went through a dozen or more before I found one with no "flat" spots.

 

[PCeBiker]

I did a lot of experimenting as well. The trick was to find a miniature pot that would fit in a small case, mountable so the switch & pot could be thumb controlled.

I connected the potentiometer directly to my throttle in parallel and ended up with two throttle controls.
Which ever throttle was set the highest took control.

If that won't work for your controller, you could mount just the potentiometer where it needs to be and run wires to a box with the circuit and switch mounted elsewhere?

The problem with the multi-turn potentiometer, is that it's not a motor controller potentiometer, so it doesn't have its own built-in case and it's harder to mount.

I'm going to try and find a 1k ohm multi-turn motor controller.

I went through a dozen or more before I found one with no "flat" spots.

I found that I couldn't eliminate the flat spots because I would get a throttle fault at start up.

The controller needs to see ~0.8V from the throttle at start-up or you'll get a throttle fault or even worse, your bike will power up.

And if the signal voltage ever goes above ~4.0V you should also get a throttle fault.

The problem is that the active voltage range accepted by the controller to go from zero throttle to full throttle is preprogrammed into the controller and is usually around 1.5V - 3V or so to help with safety and help with ignoring erroneous inputs.

So I had to leave the dead spots in to not piss off my controller.

Another problem is that if the ground wire falls off or disconnects, a hal sensor throttle goes to maximum throttle (4.1V on my e-bike) instead of 5 volts that would trigger a throttle fault.

I managed to chose two resistors that allowed the potentiometer throttle to fault properly when the ground was disconnected, but there was no way to eliminate the dead spots in the rotation unless I adjusted the values of the resistors after startup, and that was getting way too complicated.

With a multi-turn potentiometer, all I figure I'd have to do is wind up the potentiometer about 5-6 times to get to the active area, then have a full rotation of movement of that active area.

And with the proper choice of the two resistors, the +5V that the controller was designed to recognize to shut off the motor, would be restored for safer riding, if your ground wire falls off.

 

[6zfshdb]

Your controller operates differently than mine. I suppose they all have their individual quirks.

Yes, I could mount the pot separately, but I wanted a switch within thumbs reach as well. It made sense to put them in the same case.

 

[PCeBiker]

Your controller operates differently than mine. I suppose they all have their individual quirks.

Yeah, who knows what kind of programming is going on, but all the aftermarket controllers I've seen have the "speed set" (throttle input) printed on the box, so it's pretty much a standard parameter,..

The brake input needs to either be open or closed (low or high, +5 or 0V) when the brake is applied.

Yes, I could mount the pot separately, but I wanted a switch within thumbs reach as well. It made sense to put them in the same case.

I'm not knocking your design or your decision on how to implement it.
I bought all the parts to build my own version of your design.

I found that with my controller, I could use the +5V supplied by the controller to power two throttles at once, so I didn't need a circuit board or batteries and just the switches if I chose to use one.

I got all carried away and did my best to waterproof the motor controller dial and soldered the wires directly to the potentiometer, but I didn't like how the cable could be pulled out of the housing, so I put a stick through the opening in the housing and tied a knot around it with the cable before I sealed it up with silicone,..

I surfed through Endless Sphere as well looking for circuit diagrams of throttles and such.

I contemplated installing a torque sensor on my handlebars to squeeze with my hand to get a throttle input for my controller ?

Then I ordered a bunch of reflectors to score the handlebar clamps from them, but they came without the clamp.

I got half my money back (5 bucks) but I still didn't have any plastic handlebar clamps with the proper clamp angle and had to make it work.

Then I bought more bells and whistles to score the clamps.
This is a fancy brass bell with an aluminum bar clamp,..

It was almost ten bucks, but if it doesn't work as a throttle mount, I can use it upside down as a Fancy Ashtray.

I bought all kinds of clamps and throttles in my quest for the ultimate throttle,..

It was WAY Back when I first joined this forum that I stumbled upon your circuit and knew that that is what I wanted !!

It allows you to bypass all the logarithmic AI programming crap that studies the rider to decide how to operate the ebike.

You simply set your speed at whatever you desire and pedal along with as much or as little effort as you desire.

The only bad thing about continously variable "PAS mode speed" is that you can choose to get no exercise at all.

That's what I did.
I have put almost 10,000 km on my two e-bikes with less than 100 km on the cranks.

 

[6zfshdb]

Yeah, who knows what kind of programming is going on, but all the aftermarket controllers I've seen have the "speed set" (throttle input) printed on the box, so it's pretty much a standard parameter,..

View attachment 189657

The brake input needs to either be open or closed (low or high, +5 or 0V) when the brake is applied.



I'm not knocking your design or your decision on how to implement it.
I bought all the parts to build my own version of your design.



















I bought all kinds of clamps and throttles in my quest for the ultimate throttle,..

View attachment 189663

I've had good luck with the Matchmaker clamps. Rock solid with right & left versions:

Amazon.com

Pricey, yes but bulletproof.

 

[PCeBiker]

I keep getting stuck with the whole .COM vs .CA thing.

It comes to $65 CAD plus tax, shipping and possibly duty.

And I'd have to wait up to half a year for it to arrive.

I'm sure I can find it somewhere else with at least faster shipping, but first I have to figure out how to switch my Amazon back to .CA instead of .COM

I'll try surfing through the SRAM store on Amazon once I can get Amazon to deport me back to Canada .