Using Potentiometer inline with Hall effect throttle

[dcastillo]

My logic says this should work fine, but has anyone tried it? Want to create a simple way to adjust the max power on my sons gokart. not only for him depending on where we are riding, but incase other little kids want to ride it I can slow it down.
thoughts?
Danny

 

[itsid]

none tbh...

resistors are strange at least mathematically..
You put a known voltage in and all you can calc at the output is current..
you put known current in and all you'll get is a voltage calculation.

So yeah... sure it's always both.
but is the current high enough to get a reasonable voltage reading at all?
IDK tbh...
I have no idea what kind of current the pedal is powered with.. so I have no idea what kind of voltage the signal line would show per Ohm of resistance.

See.. strange

Bu it's easy to test.. find a know resistor and link it to the signal line (disconnected from the controller)
power on the controller and step on the pedal...
read the voltage and amperage with a multimeter and see what you'd need as POT-values
and if such potentiometer is at all avalable
(it'd be hard to find one that's only 0-2Ohms for example)
a much bigger one (say a common 0-10k Ohms) might not be precise enough to dial in a solid voltage signal.

Again.. I cannot tell; I have no idea.
but give it a try and see what you'll get and if it's worth it.

'sid

PS your controller is programmable, right?
Why not set up two or three powermodes and upload them when your kid's going to drive
(that way you're also assured no kid could mess with the poti setting )

[EDIT]
a hall effect throttle... why not just install a mechanical throttle stop?!
much easier IYAM... just a bolt to stop the pedal from being fully depressed and all you'll get is a -say 3V- signal and the motor is running @ 60% of it's max power at best.
a bolt and a locknut... *shrugs*

 

[Iron John]

We don't know what is inside those black boxes, so who knows? But it does not seem difficult or cause irreparable damage to try.

 

[dcastillo]

Thanx sid, maybe its the EE in me wanting to add a circuit when a bolt and nut would do

That carts controller isnt programmable
And on that note, my other kelly controller, which is programmable, doesnt allow me to set different setups/modes and toggle them with an IO line. I figured it would or at least should be able to. Doesnt seem very hard from a software point of view and would be a nice feature to have.
I may experiment with the Pot and let you know the out come, if it works it woudl be faster and better then a mechanical dead stop thats not as easy to adjust on the fly. My usage would be, set it low for the first 1/2 mile till we exit the subdivison and get to the open field, then turn it up while out there and then dial it back down on the drive home.... thats why I would like to go with the easily adjustable pot.
Nut and bolt will make a nice fall back plan

I quick search says most (at least the ones I looked up) hall effect transistors can output 8-10mA. The 1KOhm Pot shoudl draw just under 5mA and the controller I would assume has a fairly high impedance ADC on it (maybe) which shouldnt draw any current... I shoudl know by the end of the week
Ill verify the voltage swing from the throttle without the POT and then with the POT and see if I can get the same max voltage level.
-Danny

 

[dcastillo]

Just a quick update/closing on this incase anyone wants to do it on their cart...
It worked perfectly

I how have a knob on my sons gokart I can turn to go from full speed all the way to off (no throttle response)

This is great, especially once I put a bigger motor on. Means I can easily let other, less experienced, kids ride it and instantly tune it down for them. Also allows me to over power the cart with a big motor, but only enable that full power power when out in an open area, not while driving thru the neighborhood.

I highly recommend the modification to anyone in my similar situation.
(now on to adding the jackshaft and brakes)
thanx
Danny

 

[Functional Artist]

Kool concept.

Could we get some pics of your setup?

 

[dcastillo]

ugh, already bolted the setup back together...

not sure how much pics would help in this situation, but will take some next time. Maybe I should take my dads advice and actually draw up a schematic of the setup. It could be of use to someone else, especially considering all the switches, buttons, gauges and now dials I have on the thing

here is the pot I used
https://www.amazon.com/gp/product/B0002KRE1G/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

 

[dcastillo]

Heres the instrument "cluster"
dial was added to the very top

If I had time on my next cart for my 7yr old daughter, I was going to try and incorporate some type of an arduino/rasp-pi and LCD screen for her but that might be a bit optimistic

-Danny