hall throttle for CA v3.1 aux input?

E-HP · Dec 4, 2019

I've harvested parts from my last thumb throttle purchase, since it wasn't going to work out for me. I used the switch and voltmeter, replacing the parts from my half twist throttle, and threw the rest of the parts in my parts bin. Last night I was researching the aux inputs on my cycle analyst, but thought about the left over parts. Has anyone adapted the magnet and hall sensor from a throttle to used as an analog input for the CA?

My thought is to take the parts and fabricate a compact unit with a short lever that I can use to adjust my PAS power on the fly. It wouldn't have the full 0V-5V range, but I think I can do without the lowest and highest assist levels if I can get it to work. I like the idea of operating it with just my thumb, which should be easier than operating a knob on the potentiometer that I was researching.

I still need to play around with the parts to see how this idea might work.

amberwolf · Dec 4, 2019

YOu can set the voltage switching points to whatever you like (as a percentage of the range) for the aux input, in the menu here:
https://www.ebikes.ca/product-info/cycle-analyst-3.html#ca31-setup-menu
under
SETUP ANALOG AUX INPUT

WHerever it says "potentiometer" it really means a variable voltage source; that's generally a potentiometer with one end wired to 5v, the other to ground, and the wiper to the aux in.

YOu just need to make the mechanical system of your lever with enough friction so vibration won't move it.

YOu'd probably want to use the POT mode rather than the preset or switch mode, and have it directly adjust the current or power limit.

The analog auxiliary input connects via the white 3-pin connector and allows you to use a variable voltage from a potentiometer or a switch/resistor assembly to vary one of the limit settings on the fly while riding.

[ AuxA->Ctrl Type ]
Chooser to select the type of installed analog control.

Pot: A 2k-10k potentiometer. This setting can also be used for DIY circuits that present varying voltages to the AuxPOT input.

2-Pos Sw: A 2 position switch that is configured to present a low and high signal voltage.

3-pos Sw: A 3 position switch that presents 3 different voltage levels to the Aux input. The standard Grin 3-position CA switch uses resistors to provide 1.6V, 2.5V, and 3.3V for switch positions 1, 2, and 3 respectively.

[ AuxA->Function ]
Chooser to select the controlling effect of the Analog Aux control. Choices are identical to those of the Aux Digital function selections but are mutually exclusive so a selection made in one will be excluded from appearing as an available option in the other.

Off: The installed control remains configured but is deactivated. [Default]

Presets: The control selects the current preset. This option is displayed only if a 2-pos or 3-pos switch is installed; the associated preset count is automatically adjusted to match. This mode overrides the console button 'hot swap' capability as well as Prst->PowerOn.

Amps Lim: The Aux control applies a scaling factor to the configured MaxCurrent setting.

Speed Lim: The Aux control applies a scaling factor to the configured MaxSpeed setting.

Power Lim: The Aux control applies a scaling factor to the configured MaxPower setting.

ThrO Lim: The Aux control applies a scaling factor to the configured ThrO-> MaxOut voltage. With most controllers this has the effect of limiting speed by a means that is easier to tune but less precise than true speed limiting.

PAS Level: The Aux control scales the final applied pedal assist level. This is one of the most common uses for the Aux Input devices. If there is a cadence dependent term to the PAS output, the scaling applies to the final output including the RPM component.

[ AuxA->Lo Deadband ]
This option is present only for pots configured for a limiting function (non-Preset).

Specifies the voltage offset above the baseline voltage at which the pot will be considered to be at MINIMUM setting. This setting typically ranges from 0.1V to less than a volt and can be tuned to set the point where the potentiometer crosses 0%

[ AuxA->Med Sw Level ]
This option is present only for 3 position switches configured for a limiting function (non-Preset).

Specifies the percentage of the configured maximum limiting parameter (MaxCurrent, MaxPower, MaxSpeed) for the MEDIUM switch setting for 3 position switches. The HIGH setting is assumed to be 100%.

[ AuxA->Hi Deadband ]
This option is present only for potentiometer devices.

Specifies the voltage offset below 5V at which the pot will be considered to be at MAXIMUM setting. This setting typically ranges from 0V to less than a volt and can be tuned to reduce deadband. A proper setting shows a full rotation value of 99% that decreases shortly after the pot begins to be turned downward.

[ AuxA->Lo Sw Level ]
This setting is preset only for switches configured for a limiting function (non-Preset).

Specifies the percentage of the configured maximum limiting parameter (MaxCurrent, MaxPower, MaxSpeed) for the LOW switch setting for 2 or 3 position switches. The HIGH setting is assumed to be 100%.

E-HP · Dec 4, 2019

Thanks! That even better than I thought. I’m going do some testing tonight to see how the sensor functions so can design a unit that will work the way I want.

Sent from my iPhone using Tapatalk

amberwolf · Dec 4, 2019

NOw, that said, If you set up the cadence PAS correctly for your stuff, you don't really need levels for the assist, because it's not just on/off like generic setups are--it's proportional, just like the throttle, because it's controlling how much throttle the controller actually gets.

You can still use them if you want, but it's not really necessary, unless you have a huge amount of power and a very light bike and rider (maybe not even then depending on how you set it up).

For the trike, I have it more or less like I want it, other than having to use throttle to start from a stop because it's too heavy for me to stand the pain of starting up just pedalling.

I'm using just Cadence PAS, with it set for 10% throttle upon initial cadence detection, then 1.25% throttle for each RPM once detected. (the numbers might not be quite what I'm using now, but they're the last ones I made notes of; I keep tweaking it all the time to try to perfect it).

So you setup the initial throttle for a boost that won't cause you any problems, but is enough power to do what you want at minimum cadence. Then setup the percentage of throttle per RPM to let you get the max throttle you need at the max RPM you will spin at, (or 100% throttle at the fastest RPM you *can* spin at, if you like).

E-HP · Dec 4, 2019

amberwolf said:
NOw, that said, If you set up the cadence PAS correctly for your stuff, you don't really need levels for the assist, because it's not just on/off like generic setups are--it's proportional, just like the throttle, because it's controlling how much throttle the controller actually gets.

I'm going to be doing the same thing with the cadence setup. I was thinking, but not sure it would work this way, to use the aux input to lower the overall power when I need to extend my range to get back home (or turn it up when I'm feeling lazy). Reading the manual, it looks like the aux input would ratchet up or down the power, including the % adjustment of the cadence setup. Would that work, in order to increase my contribution when necessary?

amberwolf · Dec 4, 2019

Aux in will only control one parameter at a time. You have to change it in setup for which one it affects.

There's a number of limiters you could use the aux input to control that would help extend range.

Power limiting is probably the best one to try first, but you can experiment with any of them.

I would try it all with the pot you have first, to see which one does what you want best, and then come up with your hardware to replace the pot once you know the kind of input range you need.

If you wanted (and have the designer skillz) you could even make it automatic, with a high resistance voltage divider from the CA's power input to ground, to "scale" the battery voltage to a lower voltage. Then input that to an Op-amp circuit that scales the small range of change in battery voltage as it discharges to be within the 0-5v aux input range, but as close to the min and max of that as possible. Then use the aux input to limit current or power, or even throttle max percentage. As the battery discharges, the limiting gets more severe. If the op-amp circuit is setup as nonlinear, it can even make it limit *much* harder at lower SoC than full charge.

E-HP · Dec 4, 2019

amberwolf said:
If you wanted (and have the designer skillz) you could even make it automatic, with a high resistance voltage divider from the CA's power input to ground, to "scale" the battery voltage to a lower voltage.

OK, now you're talking. Maybe another application of the automatic feature would be to introduce a rotary motion or level sensor of some kind, that mounts in a direction to detect when the bike is climbing, descending, or on flat ground. It could adjust the overall PAS power based on that input. The PAS is the whole reason I got the CA for, so I can see what kind of things you can leverage from its features. :bigthumb:

First hit looks like there may be some sort of sensors out there. I think they'd work correctly under braking as well, adding more power when accelerating, and letting off when deaccelerating (need to think about that some more). There might need to be some kind of delay or normalizing circuit so it doesn't act twitchy. Maybe something fluid based.
https://www.arrow.com/en/products/640es103a06naay/honeywell?gclid=EAIaIQobChMIgo7s1s2d5gIVKSCtBh0bEgUkEAQYBSABEgIz9_D_BwE

I imagine it might perform like the combination of a cadence and torque sensor, or have the benefits of each, if designed correctly.

EDIT: If the Potentiometer setting is only looking for voltage, then the input doesn't necessarily need to be analog. So, a set of say, 5 liquid level sensors could be used with a reservoir of some sort, using sensors like these:
https://www.amazon.com/EPTTECH-Optical-Infrared-Sensibility-Controller/dp/B075R6SSHJ/ref=pd_sbs_328_t_0/136-3864138-8481938?_encoding=UTF8&pd_rd_i=B075R6SSHJ&pd_rd_r=412742b6-4990-491b-a30f-797d18425066&pd_rd_w=MNlgz&pd_rd_wg=ZnuKC&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=TGGWXPGDG8WV93MG1S3W&psc=1&refRID=TGGWXPGDG8WV93MG1S3W

amberwolf · Dec 4, 2019

You don't want something that automatically applies more power because of acceleration itself, or it will just ramp up to full power and stay there until you shut it down (assuming you have a way to do that).

Same thing for auto-deceleration, it'll just grind to a stop and hold there.

All you would really want is something that gives you more boost when you need it, and doesnt' do anything at all when you don't.

There are a lot of automated limiting / boosting things you can do using the CA3 with external sensors, and a fair bit of creativity and working out settings in it.

If you use just the Aux input, you can really only do one of them at a time, because it only has one aux input and that can only be used to modulate one thing at a time.

But actually it has a number of inputs:
--Analog input for throttle in (THin)
--Ebrake in (on/off only)
--Temperature sensor input (which doesnt' actually have to be a temperature sensor...it's an analog input you could use to sense anything within the voltage range...but it only gets read by the part of the CA monitoring temperatures, so it will only be able to modulate things that can be affected by that).
--torque sensor analog input (analog)
--cadence sensor pulse input (on/off)
--cadense sensor direction input (on/off)
--current-measuring shunt input (analog)
They all have dedicated purposes, but if you get creative with your thinking, and don't need them for their actual purpose, you can use them for other inputs as long as you can work out a way to make the input you want to use modulate something it's capable of modulating.

You just kinda have to know what the CA can actually do, and kinda how it does it, which is covered in the CA3 info page previously linked, and Teklektik's UUG (linked on taht page), and the CA3 beta thread (linked on that page). Just takes a fair bit of time to read, and for me even longer to understand what's going on. Even now, years after starting to use one, I'm just now beginning to understand how some of the interactions between settings work and can be used to do stuff I need it to do. (and to be certain that it *cant'* do some of it).

A torque sensor on the cranks would in theory let you get more boost on hills vs flats, or against high headwinds, etc., because you'd be pedalling harder, but I havent' been able to get mine to work like that (TDCM; also have a THUN but not on the trike); the CA doesn't appear to use the torque sensor in a way that applies to what I need, because I *only* need the torque to work at startup before I can spin the cranks, after that cadence does what I want for the most part.

It probably would do it for a "normal" bike under those conditions, so for you it'd probably work. If you are interested in trying it, I could loan you the THUN BB out of the old CrazyBike2 frame, so you can see if the idea works (it only senses the left crank, IIRC, TDCM does both). If not, just send it back to me. (if you'd pay shipping both ways, which should be cheap enough USPS flatrate PM....if you find you like it you could buy it from me cheap).

amberwolf · Dec 4, 2019

E-HP said:
EDIT: If the Potentiometer setting is only looking for voltage, then the input doesn't necessarily need to be analog. So, a set of say, 5 liquid level sensors could be used with a reservoir of some sort, using sensors like these:

The Presets mode works using up to three voltage levels, using a voltage divider on a three position switch. So you can use any voltage that's within the input range of the port, whether that's a continous sweeping range, or a stepped voltage, or several discrete voltages.

It can even be used for two different kinds of input at once, using the DigiAux feature, to have that be increment/decrement buttons, while still using the analog range of the same input (to a large degree) for something else. See the CA3 info page on how that works.

E-HP · Dec 4, 2019

amberwolf said:
The Presets mode works using up to three voltage levels, using a voltage divider on a three position switch. So you can use any voltage that's within the input range of the port, whether that's a continous sweeping range, or a stepped voltage, or several discrete voltages.

It can even be used for two different kinds of input at once, using the DigiAux feature, to have that be increment/decrement buttons, while still using the analog range of the same input (to a large degree) for something else. See the CA3 info page on how that works.

But the potentiometer setting has more levels, right? This position sensing stuff is pretty interesting. I think I'll go with my hall sensor thing, and experiment with different position sensors to see what they're capable of. Also, the controller has a 3 position switch as well, so a lot of things to test out.

On a side note, do you think, using current technology, but probably programming (or maybe it already exists), and for the ultra-lazy....cruise control with auto-regen, so even if you are on a steep descent, the bike will just apply variable regen automatically to keep you at your cruising speed?

amberwolf · Dec 4, 2019

E-HP said:
But the potentiometer setting has more levels, right?

Yes, but it only affects a single parameter, whichever you've set it to of the available ones.

Presets can affect multiple parameters (not all of them, unfortunately) at the same time, making them also useful for certain things the other can't be.

So...depending on exactly what you want it to do, preset mode could be more useful even though it hasn't got nearly the "dynamic range" that the potentiometer mode does. Probably not what you would want to use for your purpose...but it could be (and you might be able to use the digiaux mode along with preset mode to get the other functionality you're after--I don't know if they can be used at the same time but you can check that if it's interesting).

On a side note, do you think, using current technology, but probably programming (or maybe it already exists), and for the ultra-lazy....cruise control with auto-regen, so even if you are on a steep descent, the bike will just apply variable regen automatically to keep you at your cruising speed?

I *think* that's already available in the CA3, I forget which firmware it started in. I know that if you have a speed limit set, it can be set to use regen to help limit to that speed; I would expect that autocruise would do the same thing (but they might not be interconnected).

Easy to test, though. Setup the limit-speed-with-regen thing, then use autocruise at a low speed, then go down a hill that would speed you up beyond that, and see what happens.

hall throttle for CA v3.1 aux input?

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