# TPS vs Hall-effect throttle



## lowcrawler (Jun 27, 2011)

Differences? Which is better? If possible, I like to get first-party products - so given a soliton controller, I lean to a soliton pot-pox.

However, Hall-effect throttles also appear to work and by many accounts are 'better'.

It all seems the same to me... so what are the practical differences? Are there any in real life use, or is it all a theoretical argument?


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## piotrsko (Dec 9, 2007)

The sol throttle IS a hall sensor. They are better because they should fail in "off" mode ( due to lack of signal change) whereas a pot box is primarily a variable resistor which can fail anywhere, from off to full on. Pots also tend to get physically dirty and then have noise issues which leads to bizarre affectations when driving. All the major manufacturers use Hall sensors.


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## Tesseract (Sep 27, 2008)

The TPS we use for our throttle assembly is actually a potentiometer. It's the same one as used by the OEMs, though, and they overwhelmingly prefer them to Hall effect for the usual reasons (good enough reliability; much lower cost).

It is true that the Hall effect sensor is fail safe in that a loss of either power or ground should result in 0V output. On the other hand, Hall effect sensors work by producing a voltage proportional to an external magnetic field, and guess what there is plenty of in an EV? External magnetic fields. They are so strong at 1000A that the 2/0 motor cables on our dyno push apart a good 12-18". It never fails to amaze people the first time they see that. No one expects big cables like that to move on their own 

At any rate, Hall effect sensors can be shielded from external magnetic fields, but it just makes the whole assembly more expensive and, well, the pot in a proper automotive-grade TPS (not the kind used in some golf cart controller's "pot box") will generally have an electrical life of 10 million+ rotations.


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## tomofreno (Mar 3, 2009)

I had a PB6 potbox and after about 1 year it became "jumpy" or erratic, as a number of people have reported. For example, when I pushed the pedal slightly it might jump from 40A to 180A, the car would jump forward, then it would settle down to 60A or so where it should have gone. I found it was worst in very hot weather. I replaced it with a Hall throttle last summer from here (scroll down to see it on the lower right):
http://shop.transatlanticelectricconversions.com/main.sc
It is in the same packaging as a PB6 so it bolted right in with the same bolts. I've had no problems since. It sits in the same aluminum box as my shunt and main contactor, on the opposite side of a metal divider.


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## GizmoEV (Nov 28, 2009)

That is a great find tomofreno. Such a simple idea. It looks like it will work with any controller expecting a PB-6 or equivalent.


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## Tesseract (Sep 27, 2008)

That is an interesting find, tomofreno, and very reasonably priced, too... maybe we can stop making throttle assemblies, then. 

If you have mounted the "PB-6" in the same box as your shunt and contactors then it likely is shielded - ie, it has a closed flux path around the magnet and sensor. 

However, it can't be used with controllers that require a 0-5k variable resistance (ie - the Curtis 1221, 1231, etc.) because it does put out a 0-5V signal. I suppose you could use the Hall effect sensor to control a digital pot chip if you really needed the variable resistance type of behavior, but that would make the potbox higher tech than the controller...


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## tomofreno (Mar 3, 2009)

> It looks like it will work with any controller expecting a PB-6 or equivalent.


 It bolts in to the same mounting holes as a PB-6, but the controller must be able to operate off a 0 - 5V input rather than a variable resistance. My controller can be programmed to work with about 4 different throttle types. I had to change the throttle type parameter in the software to throttle type 2 and wire the throttle output to different inputs on the controller.


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## brainzel (Jun 15, 2009)

tomofreno said:


> I had a PB6 potbox and after about 1 year it became "jumpy" or erratic, as a number of people have reported. For example, when I pushed the pedal slightly it might jump from 40A to 180A, the car would jump forward, then it would settle down to 60A or so where it should have gone. I found it was worst in very hot weather. [...]


Damn! I got exactly this feeling at the pedal and see these jumps at my ampmeter the last few days :-(

I was wondering and had no idea where to look, because the potbox is just a few month old ... maybe half a year.



Tesseract said:


> [...]However, it can't be used with controllers that require a 0-5k variable resistance (ie - the Curtis 1221, 1231, etc.) because it does put out a 0-5V signal. [...]


Double damn! ;-)

So if no replacement part is out there, what could I do (Curtis 1231C)?
Tear apart and clean it or replace the resistor/poti part?


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## frodus (Apr 12, 2008)

here's a replacement:
http://www.tecknowledgey.com/catalog/product_info.php?cPath=54_55&products_id=464

It's a 40 degree pot, so it's not a standard 90 or 360 degree pot. 

Either do that, or get a soliton throttle. There are others out there though. You could use a throttle body off another vehicle and just use that assembly if you wanted. Has the cable interface and the pot all on the body of the throttle.


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## lowcrawler (Jun 27, 2011)

So let me get this right -- a Hall-Effect is 'better' if your controller can handle it AND you sheild that actual TPS (by putting it in a metal box)?


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## cruisin (Jun 3, 2009)

You can do away with all the wire cables, springs, etc and use one of these which I have had excellent results with. It is a 3 wire and has a 2 wire NO switch as well. Also used 2 of them as I needed a pot to work off the brake pedal for Brake regen. The NO switch on the Brake pot then operates the brake lights.


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## lowcrawler (Jun 27, 2011)

So the Hall-Effect TPS's are generally located AT the pedal and just transmit the variable voltage to the controller via a standard (shielded) cable. 

Given that, what needs to be sheilded -- the cable, or the actual 'sensor' at the pedal.

Great photos, cruisin.


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## cruisin (Jun 3, 2009)

lowcrawler said:


> So the Hall-Effect TPS's are generally located AT the pedal and just transmit the variable voltage to the controller. (yes, I see netgain makes one mean for cable-connection)
> 
> Given that, what needs to be sheilded -- the cable, or the actual 'sensor' at the pedal.
> 
> Great photos, cruisin.


The ones I use are not Hall Effect as I prefer the pot type. No need to shield and you just run 2 or 3 wire to the controller. Pedal is full adjustable for comfort.


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## Qer (May 7, 2008)

lowcrawler said:


> So let me get this right -- a Hall-Effect is 'better' if your controller can handle it AND you sheild that actual TPS (by putting it in a metal box)?


No. A high quality throttle is better than a low quality one, the same as with controllers, chargers etc. You get what you pay for.

I have a background from music and radio broadcast and in those areas Alps potentiometers have an almost mythical reputation (at least in Europe), but they've earned it too. They can run for decades without service and if you even do proper maintenance every now and then they're virtually impossible to wear out. There's nothing magical over them, they're just very good potentiometers. Their pro quality sliders for mixer boards can also easily cost ten times more than the cheap stuff. Or more...

As I said, you get what you pay for. Personally I'd choose a high quality potentiometer over an el cheapo hall-effect 10 times out of 10. And the opposite, of course...


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## brainzel (Jun 15, 2009)

So, which one is the "high quality potentiometer" 0-5K, which would probably last a long time and where could I get one?


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## Tesseract (Sep 27, 2008)

brainzel said:


> So, which one is the "high quality potentiometer" 0-5K, which would probably last a long time and where could I get one?


Are you asking about the actual pot, or a complete throttle assembly?

The usual trick for a Curtis PB-6 replacement without buying that weird, yet crappy, pot is to get a quality standard pot of a higher value than 5k such that when you only use a fraction of it's rotation you end up with ~5k max. The usual recommendation is to buy a 25k pot but I can't quite see how that works if only 40 degrees of rotation is truly used as most standard pots have 300 to 330 degrees of active element. At any rate, it might be worth searching through the available parts of 25k to 50k in value. Qer says that Farnell is a popular supplier in the EU so maybe start plowing through the datasheets of what is available from them?


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## brainzel (Jun 15, 2009)

Whole thing or only the potentiometer would be both ok.
The main thing is a good usability and durability.

Thank you for the Farnell hint, I'll look through there product catalog and try to find a good potentiometer.


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## palmer_md (Jul 22, 2011)

http://www.evworks.com.au/index.php?product=CTL-ZEVA-DPA

How about this?


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## brainzel (Jun 15, 2009)

Tesseract said:


> [...] The usual recommendation is to buy a 25k pot but I can't quite see how that works if only 40 degrees of rotation is truly used as most standard pots have 300 to 330 degrees of active element. At any rate, it might be worth searching through the available parts of 25k to 50k in value. [...]


I disassembled a "PB-6 lookalike poti" from fourthgen this weekend.
The pot was OK, I replaced it because of the mechanical assembly which lost bolts and screws by vibration.

The pot is 20K ohms, restricted to 5K (4,7K) by the angle of the mechanic.



palmer_md said:


> http://www.evworks.com.au/index.php?product=CTL-ZEVA-DPA
> How about this?


Thank you Palmer, just a few hours to late so I placed an order just befor for a hopefully better quality 5K pot.


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## EscapeVelocity (Nov 12, 2010)

Has anyone used a Kelly Controller hall effect pedal? I use their grip throttles on my motorcycle and they've worked reliably over 3000+ miles.

http://kellycontroller.com/kelly-kp-series-5v-throttle-pedal-p-133.html


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## Ace_bridger (Nov 22, 2011)

Potentiometers are somewhat out dated now. I know the EV market still use them but really the street and race automotive world use Hall Effect now.

The fact that a Hall Effect sensor is contactless means expected life is much better than that expected from a contacting potentiometer, by several orders of magnitude.

***While I'm here, can we please distinguish between potentiometers and variable resistors. A potentiometer is a 3 wire device which is supplied with a voltage and gives out a variable voltage dependent on position. A variable resistor is a 2 wire device which shows a varying resistance dependent on position.***

If you're not using Hall Effect yet then you probably will be in the future should you up grade.

Hall Effect sensors might need shielding from strong external magnetic fields and this should be done using a material with high permeability such as a radiometal or mumetal. There's no point just making a cover out of any old metal as you need it to be high permeability such that the magnetic field flows through it rather than passes through it. A material with high permeability means that it has low reluctance and magnetic fields can pass along or through the material. The best analogy I can think of is it being like the flow of water, the water will take the path of least resistance.

Potentiometers have lower expected life and can suffer from noisey outputs should you get any build-up of crap as the resistive track wears.

The Formula One world moved over to Hall Effect a few years ago after using pots widely.

My advice,

1) go Hall Effect and ideally buy a controller which accepts a 0-5V input
2) if your controller doesn't accept 0-5V the use a Hall Effect TPS and a conversion board as previously shown
3) site the Hall Effect TPS away from wires carrying high current and way from the motor
4) if your Hall Effect behaves eratically then, and only then, shield the Hall Effect TPS.


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## Duncan (Dec 8, 2008)

_I know the EV market still use them but really the street and race automotive world use Hall Effect now.

_Are you sure? - all of the automotive TPS sensors I have seen are resistive - and they last for ever

A well designed "pot" will last for many millions of cycles_ -_ and you don't need the shielding and the worry about wires


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## DJBecker (Nov 3, 2010)

Ace_bridger said:


> Potentiometers are somewhat out dated now. I know the EV market still use them but really the street and race automotive world use Hall Effect now.


The production automotive world still widely uses potentiometer TPSes.

There is a trend toward using hall effect throttles, but it's quite gradual. 
The switch often happens when the control system changes to throttle-by-wire, putting the TPS inside the passenger compartment rather than on the throttle body. 

Hall effect pedal sensors aren't necessarily more reliable, just slightly more diagnosable. Before throttle-by-wire, the system had a mechanical fail-safe with the throttle plate. The TPS is usually mounted on the far side of the throttle plate shaft so that it detects the position past most mechanical failure points. Sensor failure didn't introduce any new risk. When changing to throttle-by-wire, it's important to add at least one *new* failure detection mechanism to substitute for the far greater consequences of an erroneous reading.

As far as real-world reliability, it appears that the well-publicized Toyota hall effector pedal problems are far more numerous and troublesome than traditional potentiometer TPSes.


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## Ziggythewiz (May 16, 2010)

Ace_bridger said:


> ***While I'm here, can we please distinguish between potentiometers and variable resistors. A potentiometer is a 3 wire device which is supplied with a voltage and gives out a variable voltage dependent on position. A variable resistor is a 2 wire device which shows a varying resistance dependent on position.***


Are you sure about that? I think if you run voltage through a variable resistor you'll get a varied output out.


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## frodus (Apr 12, 2008)

A variable resistor is basically the resistor and a wiper. Just those 2 pins. It may be part of something that essentially acts as a voltage divider, but just by itself it's not.

A pot is a 3 wire device that is essentially a variable voltage divider. You put +V and Com the two outer pins, and the wiper goes to the signal input of the device. It varies between +V and 0V. It could also be used as a variable resistor by eliminating 1 of the pins and just using the remaining pin + wiper.


It's all semantics anyway, not many "variable resistors" out there are being used for a throttle..... I think he was just being a little picky with terms.


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## Ace_bridger (Nov 22, 2011)

frodus said:


> ..... I think he was just being a little picky with terms.


OK, I might be wrong about production cars being Hall Effect, sorry that was an assumption on my part.

But Frodus, I am not just being picky about terminology, they are different beasts. A pot will give a variable resistance if you connect between ground and wiper or Vs and wiper but they are not designed to operate like that and you can expect to get noisey outputs and will not get the long life of which has been quoted here.

I design inductive and potentiometric sensors for primary flight controls, secondary flight controls and fuel controls of aircraft. Before that I designed rotary and linear potentiometric sensors for Formula One, World Rally Car, British Touring Car, etc. I'm NOT saying 'oooo, look at me, I'm great' just that I have some experience with these things and know what's inside and how they are designed.

Motorsport turned away from pots a few years ago due to reliability issues. Perhaps due to the extreme environment and perhaps they only need them to work for short periods but in an EV application I would expect my Hall Effect to last forever, essentially.

I'm having an F1 hall effect on my car as I have a few on my desk.


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## Ace_bridger (Nov 22, 2011)

Ziggythewiz said:


> Are you sure about that? I think if you run voltage through a variable resistor you'll get a varied output out.


You could put a voltage across a variable resistor but it only has two wires so you'd have no way of tapping off a voltage.

A variable resistor has relatively high contact resistance, in contrast to a pot. A pot has low contact resistance as the potentiometric track is quite soft and wears quickly with high contact resistance. This is why I wouldn't recommend using a pot as a variable resistor and why people experience noisey signals when they do. Different beasts.


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## frodus (Apr 12, 2008)

I still think you're being picky about terminology. Some controllers have only the option to a pot as 2 wire, not 3.

People get it, you build HE sensors. Go have a beer and relax.


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## Ace_bridger (Nov 22, 2011)

frodus said:


> I still think you're being picky about terminology. Some controllers have only the option to a pot as 2 wire, not 3.
> 
> People get it, you build HE sensors. Go have a beer and relax.


OK, I've had a beer and I am always relaxed! 

I'm not being picky, they are different animals.

Potentiometer: i.e. variable potential i.e. variable voltage

Variable resistor: variable resistance

It's not complicated, the technically minded folk on here will appreciate the difference. 

...and I don't build HE sensors...I design Linear Variable Differential Transformers (LVDTs)...the stuff that keeps the travelling public airbourne. I'd try and explain LVDTs but I think I'd be wasting my time!! 

You keep using pots as variable resistors. While you're wondering why you have a noisey output, erratic performance and short life please think of me and I'll have my hands on my hips with my head rocked back laughing !! 

I've been a forum goat long enough on this and I'm bored of banging heads so I'm off to work on my F1 style 'throttle'. Enjoy your pot, man!!


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## frodus (Apr 12, 2008)

I'll be using my HE throttle, thank you very much..... wasn't ever arguing that there isn't a difference. I completely agree they're two completely different things. What I don't agree with is your tone.....

People get it. You're smart. You know the difference.... Congrats!!!..... I'm an EE, I totally know the difference and have explained this time and time again to people.... the issue is your holier-than-thou attitude.... and condescending attitude. You know it's completely possible to explain to people without being a complete prick, right?

You go ahead and rock your head back and put your hands on your hips, but you won't be laughing at me..... I'll be laughing at you and your funny dance.


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## GizmoEV (Nov 28, 2009)

I read somewhere that Hall Effect devices can be affected by extreme cold. I don't recall what happened but maybe it was that the output voltage range changed or something.

I know on my rig I had the variable regen voltage settings just inside what my HE throttle put out and had to narrow the range at the bottom end because when the temperature got cold regen wouldn't quit when I let off the throttle trigger. I had to manually cancel regen mode until I made the controller setting change.

In any case, I take blanket statements as automatically suspect. There will typically be special cases where the statement doesn't apply.


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## cruisin (Jun 3, 2009)

Ace_bridger said:


> OK, I've had a beer and I am always relaxed!
> 
> I'm not being picky, they are different animals.
> 
> ...


I think what Travis is saying is that the persion buying a pot for his controller has been limited to the pot that the controller was designed for. When the controller supports both kinds as you have mentioned, most will buy what they can get the cheapest because they dont see the advantage of one over the other for a short term. They may avoid the Field Effect because of the potential noise problem. Others say just buy a cheap Curtis knock off pot because theirs have been in use for years without a problem. My 2 cents.


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## EVfun (Mar 14, 2010)

I miss the non-contact inductive throttle used on the old DC Power Systems controllers. That said, my buggy has been sporting the same Curtis PB-10 0-5000 ohm 2 wire "pot box" for the last 12 years.


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## Ace_bridger (Nov 22, 2011)

frodus said:


> I'll be using my HE throttle, thank you very much..... wasn't ever arguing that there isn't a difference. I completely agree they're two completely different things. What I don't agree with is your tone.....
> 
> People get it. You're smart. You know the difference.... Congrats!!!..... I'm an EE, I totally know the difference and have explained this time and time again to people.... the issue is your holier-than-thou attitude.... and condescending attitude. You know it's completely possible to explain to people without being a complete prick, right?
> 
> You go ahead and rock your head back and put your hands on your hips, but you won't be laughing at me..... I'll be laughing at you and your funny dance.


I appear to have upset you. I appreciate that as a Senior Guy you have a level of knowledge which is respected here. I'm sorry you feel the need to verbally abuse me because I know more about one aspect of what we discuss here. I'll be reporting your post to the administrators once I can figure out how! 

Having anonymity on-line often makes people very agressive. People say things that they wouldn't normally. I'm sure you wouldn't speak to me, or anyone else, like that face-to-face.


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## GizmoEV (Nov 28, 2009)

Ace_bridger said:


> Having anonymity on-line often makes people very agressive. People say things that they wouldn't normally. I'm sure you wouldn't speak to me, or anyone else, like that face-to-face.


That is true. You definitely prove your point. Travis has posted his whole name. You, on the other hand, have not that I have found.

The tone of your original post to this thread basically said that any one who doesn't use a HE device for throttle is a stupid idiot, you know as the god of all HE and potentiometer knowledge

Could it be that you wouldn't have said it the way you posted it if you were talking with Travis or any one else face to face? I can guarantee that what I type is exactly what I would be saying to you if we were face to face. Your original post could have been much shorter and accomplished getting the information across in a more helpful manner if you had simply asked why people continued to use pots, either 2 or 3 of the wires, when HE devices were superior.


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## Woodsmith (Jun 5, 2008)

Please stop with the name calling, negative attitudes and negative assumptions about each other.
Many members here have their own opinions, some learned some not. Many also have real world experience, some extensive, some limited.

A discussion should be just that, a discussion. If you can not speak nicely to the whole world, as that is the extents of the readership, then please refrain from speaking badly, of each other or of each other's knowledge or experience.
If you disagree with another member's opinion then say that you disagree and then explain why. If you feel terms used are not accurate then accept that it may be a 'common use' term or a difference caused by nations seperated by a common language.

Also please consider that sometimes what you intended to say when you post may not come across in the same tone to another reader and offence or misunderstanding may be caused.
I doubt very much that there is any member here who knows everything and sometimes a litte humility, tact and understanding of each other's views can go a long way.

Lets keep this a friendly, and family friendly, forum. 

Please also take a moment to read the prohibited content.

Thank you
Admin


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## Ace_bridger (Nov 22, 2011)

I didn't quite realise how sensitive people are on here.

I didn't mean to cause offence so apologies if I did. I like an intellectual discussion with like minded people, that's all.


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## frodus (Apr 12, 2008)

Ace, I felt you had a negative tone and I mentioned there are other ways to address people. I would totally tell you the same thing in person. I appologize if I offended you. Lets both take more time to re-read our post before we hit send.


That being said, let me mention a few things:

- Sometimes people are limited so they cannot use a hall effect easily. Example is alltrax, which can use a HE, but you need an isolated DC-DC for the HE because the throttle input references B- and the Alltrax has no accessable 5V supply.
- It can be hard to find an off the shelf solution from a reputable vendor that can take a cable actuated input and mount in the vehicle easily.
- Sometimes the cost of a hall effect sensor makes it too expensive for their budget
- Sometimes when people say variable resistor, they mean Pot. 
- When people can, I've seen them use 3-wire throttle or hall effect.
- I've heard very few builds have issues with 2 or 3 wire pots.
- I've heard of more problems with HE from international vendors, ebay, etc.... than I have with Pot's.
- In the lab we might find a 2/3 wire pot to be noisy, but I think this hasn't been a real issue with the controllers that we use. They're not overly sensitive and It's very possible there's some filtering inside the controller to limit this.

Hall effect are good when they can easily be integrated into a controller. When it can't, then a 2 wire throttle should be just fine, but obviously it's not preferred. 

The three wire would work just fine on my motorcycle, but I found a nice drop-in replacement for my Curtis PB-6 with 90degree rotation, 0-5V output and it's fairly inexpensive. I like that it's of higher quality, sealed and from reputable vendors.


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## Ace_bridger (Nov 22, 2011)

Thanks for the apology Travis. I genuinely didn't mean to cause anybody any offence and have reread my initial post, all of them actually, and I don't see it as offensive so I put it down to cultural differences and, as Woodsmith says, being seperated by a common language!! I lived and worked in the US so I know how these things can happen.

Even if my post was taken as being somewhat hollier than though I don't think it was appropriate to be abusive or to use foul language, as admin have commented, so many thanks for the apology.

I've just bought a throttle body with a resistive TPS with the intention of changing it out for Hall but if it works fine I bet I'll be tempted to use it!! 

Adam


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## coulombKid (Jan 10, 2009)

frodus said:


> A variable resistor is basically the resistor and a wiper. Just those 2 pins. It may be part of something that essentially acts as a voltage divider, but just by itself it's not.
> 
> A pot is a 3 wire device that is essentially a variable voltage divider. You put +V and Com the two outer pins, and the wiper goes to the signal input of the device. It varies between +V and 0V. It could also be used as a variable resistor by eliminating 1 of the pins and just using the remaining pin + wiper.
> 
> ...


So if I have a 2-wire variable resistor fed a fixed voltage to ground my controller gets is control signal from an A/D converter sensing current? (4-20 ma?)...... and if I have a three wire device I'm measuring voltage out 0-5 volts DC and sensing voltage through an A/D converter to scale to throttle angle/percentage?


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## frodus (Apr 12, 2008)

Coulomb Kid,

How do you feed both a voltage and ground to a resistor at the same time.... as well as have a signal come off it? That would be 3 wire.

And the second question isn't in the form of a question.... 

What type of throttle you can use depends fully on the controller you're using.


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## Guest (Feb 16, 2012)

If you happen to be one that needs a pot then just get a good one like this. I have had excellent results and very smooth operation out of my controller vs the PB-6 style Pot. My Synkro can use a pot or HE but my Kelly can only use a POT. So the quality one is the only way to go. The cheap PB-6 is for golf carts not cars.


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## DJBecker (Nov 3, 2010)

coulombKid said:


> So if I have a 2-wire variable resistor fed a fixed voltage to ground my controller gets is control signal from an A/D converter sensing current? (4-20 ma?)...... and if I have a three wire device I'm measuring voltage out 0-5 volts DC and sensing voltage through an A/D converter to scale to throttle angle/percentage?


You've worded that awkwardly, and it would be easy to misinterpret.

Usually communicating using current mode is preferred. It has better immunity to electrical noise.

But in this case, a variable resistor works best set up as a potentiometer in pure voltage mode (three wires), rather than as a rheostat changing the resistance and therefore current (two wires).

The reason for this is that vibration can change the wiper pressure, and thus the contact resistance. The resulting noise will be proportional to the current flowing through the contact.

If you are using the variable resistor in pure potentiometer mode, with trivial net current, the effect will be minor. If it's a "loaded" potentiometer e.g. with a high-value resistor pulling to ground, the effect will increase. With a lower value load resistor and higher current, you can end up with the noise of a rheostat without the advantage of only two wires.

This point is often missed. It somehow "feels" safer to have a load resistor that strongly pulls the throttle input low if there is a wire break. But it can lead to more noise that needs to be filtered, resulting in a less safe system.

That said, you can avoid learning about many potential reliability and longevity problems by simply using an automotive TPS. Bosch has spent decades getting it right, including picking the right track compound hardness vs wiper pressure for a high-vibration environment. A variable resistor that's legendary for surviving beer spilled on the mixer board might work OK, but you shouldn't count on it.


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## coulombKid (Jan 10, 2009)

frodus said:


> Coulomb Kid,
> 
> How do you feed both a voltage and ground to a resistor at the same time.... as well as have a signal come off it? That would be 3 wire.
> 
> ...


If the controller was designed to sense 4-20 ma then the two-wire would have 5 volts into one wire and the wiper connected to ground. The third wire would be floating. High resistance-low current signal, Low resistance high current signal. Don't laugh, this system has been implemented before.


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## frodus (Apr 12, 2008)

coulombKid said:


> If the controller was designed to sense 4-20 ma then the two-wire would have 5 volts into one wire and the wiper connected to ground. The third wire would be floating. High resistance-low current signal, Low resistance high current signal. Don't laugh, this system has been implemented before.


I totally understand, your wording made it very difficult to understand.

"if the controller was designed to sense 4-20 mA"

That's the big "IF".... I don't know of any EV controllers that take a 4-20mA signal.

I haven't seen any Purely variable resistor situations. Usually there's a 4-20mA sender that has filtering inside. When I have seen a 4-20mA sender that is used to input a variable resistance and output 4-20mA, it's a 3-wire throttle and the sender itself has electronics inside.

Why not just use the throttle sensor that your controller is designed to use?


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## Richard Wood (Jun 27, 2008)

I've just read this thread and remain a little mystified about the usage difference between a Hall Effect and a regular Automotive 3-wire TPS as found in my car (I realise there are other differences). Do they both have the same wires with a fixed voltage, ground and variable voltage (that linearly reflects the pedal push or cable pull)?

I'm moving a question I have about TPS over here from another thread:

I have BMW 318ti E36. It has a 3-wire 4Kohm TPS connected to the ECU delivering a 0.6v (closed) - 5v (open) signal and I want to also be translating that signal simultaneously to a Kelly controller's input. That controller only has two wire input for each end of a "0-5K Potentiometer"

What do I need to do, including in terms of wiring that in (with the TPS - ECU connection remaining live)? 

Do I need one of these: http://www.evworks.com.au/zeva-digital-pot-adapter-use-hall-effect-throttles 
It is referred to as being for Hall Effect but the description then says it is for converting voltage to resistance, which seems to be what I need.

Should I just connect the TPS mechanically to a 2-wire EV pot box, ie with them on the same axle?

Cheers
Richard


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## gunnarhs (Apr 24, 2012)

Richard Wood said:


> I've just read this thread and remain a little mystified about the usage difference between a Hall Effect and a regular Automotive 3-wire TPS as found in my car (I realise there are other differences). Do they both have the same wires with a fixed voltage, ground and variable voltage (that linearly reflects the pedal push or cable pull)?
> 
> I'm moving a question I have about TPS over here from another thread:
> 
> ...


Hi Richard , 
It seems that your throttle gives a voltage output, that is the only thing you need. Sometimes it needs amplification or adjustment.
I strongly recommend testing the throttle by pressing the pedal and measure the voltage coming from the signal source BEFORE connecting to controller. 
Often the throttle needs a active power supply to produce the signal voltage (which means the third wire is the Power source 5V or 12V instead of 0V ground)
What kind of Kelly-controller do you have?
I have only used newer versions of throttles which can be directly connected to Kelly controller J2 (se my pin-config here below):
2-wire versions are connected to Pin 5 and 3 
3-wire : Signal 0-5V Pin 5 and 3
If third wire is ground then connect to Pin 2 (0V Power supply ground)
If third wire is Active signal 5V then connect to Pin 7 (5V Power supply) 
If third wire is Active signal 12V then connect to Pin 1 (12V Power supply)

You can match the exact voltage of your output throttle signal to the Kelly controller in the Kelly-config-Software (for example 0,6 - 4,5V)

Here are the pin definitions of my Kelly:

J2 Pin Definition 
1- PWR: Controller power supply (input) 
2- RTN: Signal return, or power supply ground 
3- RTN: Signal return 
4- 12V high-level brake and motor temperature input. Demand use KTY83-122 Silicon temperature sensors. 
5- Throttle analog input, 0-5V 
6- Brake analog input, 0-5V 
7- 5V: 5V supply output. <40mA 
8- Micro_SW: Throttle switch input 
9- Reversing switch input 
10- Brake switch input 
11- Reserved 
12- Reserved 
13- Reserved 
14- RTN: Signal return


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## Richard Wood (Jun 27, 2008)

Thanks Gunnarhs

The Kelly controller is a KDH14800D:
http://kellycontroller.com/mot/downloads/KellyKDHDUserManual.pdf
See page 8. It doesn’t have this J2 plug you mention. 

My electronically knowledgeable brother advises me that using the adaptor board I linked to above should work, just connecting the input signal and ground to the TPS, not the 5V wire ( I guess since there is already a 5V supply from the ECU).

So I’ll likely place an order for the adaptor and see how that goes.

Cheers
Richard


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## gunnarhs (Apr 24, 2012)

Ok it seems that your Kelly has a different pin-layout than mine KDC and KDH for SepEx. And the input seems to be a pot. In that case your adapter would be necessary


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## jubin (Oct 25, 2017)

*Hall effect throttle body connection details*

Dear all

I am planning to install throttle body to my engine. I am a having a hall effect throttle body. I am not sure about its electrical connections. Potentiometer type throttle bodies have 3 connectors. This too from Mikunni has three connectors. I am not sure how to use it. Can anyone help me in this regard thanks in advance?


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## goingbush (Jun 20, 2017)

Iv'e done approx 4000km on my EV LandRover conversion, The Curtis PB-6 Pot starting to get really sketchy . Deadband size is increasing & im getting less of the pedal arc translating to go juice , Not slippng linkage as I first thought.










So I ordered a Honda CRX pedal (eBay) because it looked a good match for the Landrover pedal style (just going on aesthetics) 










Not knowing if its resistive or Hall type










I measured the pins hoping for 5k value but Turns out its a Hall Effect type, I disassembled it to take a peek










Heres the U magnet that sweeps the PCB in an arc as the pedal moves










Throwing caution at the wind I noted some diodes in there so took the best guess at the polarity & came up trumps. Its got 2 sensors outputting a diferent voltage range, Pinout as follows










Hook pins 4-5-6 up as Type 1 Throttle on Curtis 1239E & BAM , make sure you use the Curtis red-white 5V feed , not 12V (or BOOM) 

I made a Plinth from Delrin to mount the pedal 










Woo Hoo , works Fantastic , much better than the PB6 EVER was .


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## MattsAwesomeStuff (Aug 10, 2017)

Neato.

I presume this means that there is not both a hall-effect and a variable resistor in there with the corresponding pins (there aren't actually 2 sensors), but, instead, some circuitry to translate the HES into ~0-5v?

I ordered an unknown type of throttle for my motorbike (actually, several different styles), and they're all HES, where my controller only has pins for 0-5v. I know there are conversion kits you can get but they're silly expensive.

Would this mean that from a junkyard I could grab an average pedal and maybe repurpose the brains in it to do the converting for me? Would anyone say this is a common thing to find on a pedal?


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## goingbush (Jun 20, 2017)

I have a higher resolution image of that Sensor , The chip is a 90277F 

googling that brings up "Dual Programmable Linear Hall Effect Sensor."

It is infact a dual sensor and has two independant HEF sensors 

as far as I know all Hall Effect throttle pedals have a similar 5v input and a linear output , different to HEF sensors as we know are use on tone wheels for ABS / speedo hall sensors

The 'extra' circuitry must be inside the chip because theres nothing smart about the other SMD components on that PCB.

https://pdf1.alldatasheet.com/datasheet-pdf/view/224120/MELEXIS/MLX90277EGOSR0-0.html


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## MattsAwesomeStuff (Aug 10, 2017)

Ugh. Had a brainfart.

Somehow parsed (and even rewrote) 0-5kOhms as 0-5v.

I'll have to actually measure and see what it uses as a voltage sense, no particular reason it would be 0-5v, but my other HE sensors are all the 0.5-2.4v range so almost certainly they're out. But does't matter anyway, since if it has an actual second HE, not something that translates the voltage, it ain't usable like that.

Hrmph. Guess I'll have to do an actual physical cable for the throttle to manipulate a potbox.


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## Duncan (Dec 8, 2008)

Hi Matt

I used a Subaru TPS - and made myself a pedal


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## Hollie Maea (Dec 9, 2009)

The Prius pedal is also a nice self contained hall effect unit, and is regularly available at a pretty good price on Ebay.


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## MattsAwesomeStuff (Aug 10, 2017)

For my use (motorbike throttle, twist grip), all the twist grips I have use Hall Effect sensors. I don't even know if there's such a thing as a twist-grip form factor potentiometer.

My controller expects 0-5k ohm potentiometer.

So, I was hoping I could electrically convert the HES into a 0-5k resistance using this dual-sensor pedal thing, rather than paying the silly (and no longer available) price for the converter thing.

For a car (my next project) it's good to know I have options, but, I'll probably end up building a controller that can take either anyway.


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## goingbush (Jun 20, 2017)

ZEVA have a converter , its cheap enough & ZEVA stuff is pretty good 

AU $55 = About US $40 

http://www.zeva.com.au/index.php?product=109


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## Frank (Dec 6, 2008)

MattsAwesomeStuff said:


> For my use (motorbike throttle, twist grip), all the twist grips I have use Hall Effect sensors. I don't even know if there's such a thing as a twist-grip form factor potentiometer.
> 
> My controller expects 0-5k ohm potentiometer.
> 
> ...


Magura makes one unless I misunderstood your need.

Sent from my Nexus 7 using Tapatalk


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## MattsAwesomeStuff (Aug 10, 2017)

Frank said:


> Magura makes one unless I misunderstood your need.


That'll work.

Problem is the motorbike is a super cheap build (I bought the rolling frame for $20, it's otherwise built from junk as a theme - and because I'm cheap).

The HES throttles are like, $5-10. These 0-5k pot throttles are $50-$100. So it's actually cheaper to buy one of the conversion thingies if it comes to that. And, I'll just make do with a cable-potbox attempt instead I think.

Thanks though, if I hadn't already ordered a couple throttles to choose from, I probably would've shelled out for the Magura.


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