Potentiometer suitable for use as a TPS.

Keith Smith

New Member
I wa s wondering if any one could give me some advice on what type of Pot to use as a throttle position sensor? I can not imagine that a garden varity carbon track type would last very long, given that the only movement will be 90 degress and likley to trend towards using a much smaller portion of that and changing on a random but regular basis. There are conductive plastic types and cement types, and of corse it will need to be able to stand up to the conditions under the bonet. Has any one had some experience with this type of sensor?


Michael 2727

Senior Member
You could use a Wire Wound type, they are usually
rated at 3 to 5 Watts and cost $10.00 bucks or so
at Jaycar, Altronics etc.
But they too will wear out.
An Opto sensor or Magnetic sensor may be a better
solution. Oatley have a magnetic throttle for their
scooters for around $10.00 bucks OZ. I think they
have a 1V to 4V output from the Hall sensor from memory.


They are called "servo pot"s.
You will know if you have found the correct type from the price.
Should start at around £20 to £60 depending on what spec you want.
The spec to look for is cycle duration.
Just because it maight say good for 5 million wipes, don't think that will last long. Consider when it is stationary and just vibrating due to noise.
How many wipes over a small area might that be?

There are also non-contact types available. Might be a better choice for a vibrating environment.


Senior Member
There are also non-contact types available. Might be a better choice for a vibrating environment.
Is this reference to a resolver?

The key to any limited motion will be the gearing of the mechanical attachment for multi-turn vs. limited turn component solutions.



Senior Member
Does it need to be a pot?

How about an LDR with a light source that is partially and progressively obscured buy your throttle movement? Or a hall effect sensor, or a capacitative sensor, or an inductive sensor. All non contact. All good for prolly a lifetime.


Is this reference to a resolver?
Unless you are making a surface mount pick 'n place robot I'd keep away from resolvers!
Very nice, very accurate & VERY expensive.
The last time I used one (around 1990) the decoder chip (16 bit per rev) alone set me back +£200. Can't remember the price of the resolver itself but probably about the same.

Somewhere in the archives, somebody posted a link to some nice non-contact drop in replacement pots. Worth a dig around to try and find it.


Senior Member
The Hall-effect scooter throttle is an excellent choice for a dirty environment (no exposed contacts), plus you get linear response.

As with all the other suggestions, you'll have to come up with a proper mechanical connection.



I actuall used one of those carbon pots as a real throttle position senser. I conected it to a real ECU.
The ECU was the RPM x Throttle position sensor type.

I few months/donuts later I replaced the pot with an Automotive type. :)

Keith Smith

New Member
Keith Smith

Thanks for all of the suggestions. I am impressed by the optical approach as suggested by Boriz, but I will also head down the path of checking out Oatley's magnetic option as well.
Once again, Thanks.