Using 0-5k throttle as hall effect?

[bbsux]

Is there a way, by adding a resistor or something, to use a 0-5k ohm throttle on a controller that uses a hall effect throttle?

Last night on my way home my cheap thumb throttle went out and I had to "jump" my controller so it was "100%" so I could get home. I have several of these 0-5k throttles and am wondering if I could use one of them...

Thanks...

 

[fechter]

Yes, you can use a resistor throttle.

The trick is to add a fixed resistor in series with both the ground and 5v legs of the throttle (connect the wiper straight to the controller). The fixed resistors will be somewhere between 1.2k and 2k, you may need to experiment a bit to get the right range.

I'd suggest 1.5k, that should be pretty close.

If the resistor is too low (or you don't use any resistors), the throttle will do nothing until you advance it quite a ways, then all the adjustment will be in a narrow range in the middle, making it hard to use. If the resistor is too high, the motor could run without touching the throttle (CAUTION: test with wheel off ground), and/or you might not reach full speed at full throttle.

 

[bbsux]

Yes, you can use a resistor throttle.

The trick is to add a fixed resistor in series with both the ground and 5v legs of the throttle (connect the wiper straight to the controller). The fixed resistors will be somewhere between 1.2k and 2k, you may need to experiment a bit to get the right range.

I'd suggest 1.5k, that should be pretty close.

If the resistor is too low (or you don't use any resistors), the throttle will do nothing until you advance it quite a ways, then all the adjustment will be in a narrow range in the middle, making it hard to use. If the resistor is too high, the motor could run without touching the throttle (CAUTION: test with wheel off ground), and/or you might not reach full speed at full throttle.

Thanks, Fetcher.

Just so I can get my head around it, is the attached gif correct?
Oh and what watt size? 1/4? 1/8? Not much current...
Radioshack has a five pack of 1.5K ohm 1/2W 5% Carbon Film Resistors for the crazy price of $0.99.

 

[bbsux]

How about this?
I'm thinking I'll get a 1k resistor and tie it to a 1K-Ohm 15-Turn PC-Mount Cermet Potentiometer/Trimmer.

It'll cost 8 bucks for 2 sets but will be adjustable and the trimmer won't easily vibrate around to a different setting...

I can use a ohm meter to set the level if I have to... then I'll know what I need for later if I need to get all resistors...

 

[fechter]

Drawing is correct.

If you use a trimmer, you could use a 2k (or even 5k) and not need a fixed resistor on the ground side.
I'd just use a 1.5k fixed on the 5v side. The high side is not as critical.

Once connected, adjust the trimmer until the motor starts to creep, then back off a turn or or so to make sure the motor will stop.

 

[Link]

There is almost no current going through these, so the regular 1/4W resistors will work. I like the trimpot idea better, though.

Not to hijack the thread, but what IS the difference between a resistive and hall throttle signal wise?

The only thing I could think of is that the hall sensor needs a higher voltage to operate than the signal needs, so using a voltage dividing pot as a throttle would cause the range on it to be off. :?

 

[fechter]

Right about the resistor wattage. Very little current flows, so even 1/8w is more than enough.

Assuming a fixed 5v throttle supply, resistor throttle output (wiper voltage) will range from 0 to 5v as the throttle is advanced.

A hall effect throttle output will range from about 1v to 4v as the throttle is advanced.

 

[fitek]

Was there a process to use a hall effect throttle with a controller that wants a 5k pot? Those Magura throttles are pretty expensive...

 

[Link]

Yeah, I remember something like that. It was pretty simple. You just used the throttle to drive a voltage regulator, or something like that.

 

[fitek]

FYI I tried two 1.5k fixed resistors on a Magura and the resulting range was very small. I also tried 1.5 and 1.8 and that was a good deal better but not good enough. Will try higher values later.