How to attach a potentiometer to a servo motor shaft

Must be dc. 12v

That covers everything from 1 cm to who knows how large.
Can you narrow it down by adding the current rating ? (or motor size in mm ?)

What about this ? (you also haven't mentioned speed criteria (degrees per second etc)

raschemmel:
That covers everything from 1 cm to who knows how large.
Can you narrow it down by adding the current rating ? (or motor size in mm ?)

What about this ? (you also haven't mentioned speed criteria (degrees per second etc)

Fogive me for being a noob. Im not fully sure exactly how to figure that out.

Here is the application.

Im automating a lawn mower. There are handle bars that pivot at the bottom. Partway uo their attached to a rod. This gives lonear motion. The end of the rod attaches to the hydro controls. I havent measured the throw distance, but somewhere around an inch at the connecting rod. The valve itself takes virtually no effort but there is a shock absorber. It may take a bit of strength to overcome the shock absorber. Im not sure how to measure it. For testing i can use my old mower without shock absorbers on.

I will need to convert the motion from the servo to linear. Putting an arm on it would work. But threat still take quite a bit of strength from the motor. The longer the lever the more torque is needed. Im just not sure how to measure it.

Rotations per minute probably depends. The higher up on the handle bars the longer the throw. The less Needed toque and slightly needed rpms per minute. But in general. Slower rotation higher torque iss needed.

I can take some pics and measurmnts when i get home. Just let me know what you need to see

Thanks

birddseedd:
I will need to convert the motion from the servo to linear. Putting an arm on it would work.

Consider a linear actuator in that case, may be the better tool for the job. There are linear actuators with location feedback. Some can even be addressed in a manner similar to servos.

To measure the force needed attach a spring scale and start pulling, see how much force you have to apply to get it moving.

wvmarle:
Consider a linear actuator in that case, may be the better tool for the job. There are linear actuators with location feedback. Some can even be addressed in a manner similar to servos.

To measure the force needed attach a spring scale and start pulling, see how much force you have to apply to get it moving.

The issue with a linear actuator is that you cannot move them manually.i would not be able to use the handle bars. I woukd have to use joysticks to control the machine in a record mode. Which would give me less control over the machine.

Side question. Will an arduino actually hold this much information?

The motor size is related to the required torque, but not directly related to the size of the shaft it is driving because shaft couplers allow two different size shafts to be coupled, but they should be roughly
the same size. the motor I linked has an RPM of 100
MOTOR SPECS

Obviously , there is no way for us to know what size motor you need since you haven't posted a drawing
of your design and you can't tell us.
By the sound of it a geared motor is what you need. The question is how big.

How much torque required to turn the valve? How many degrees from full open to closed? Have you thought about proportional flow hydraulic solenoid valves?

outsider:
How much torque required to turn the valve? How many degrees from full open to closed? Have you thought about proportional flow hydraulic solenoid valves?

The valves are built in mechanical.
The other queations i just havent had a chance to figure out. Im juat now starting to get things together

To a certain extent, some of the information can be obtain by simple manual testing.
Example, you have a valve that has a shaft. You clamp a pair of vise grips on the shaft and open and
close the valve by hand. Then you remove the visegrips from the valve and clamp on the motor shaft and turn on the motor and tell it to turn (slowly) one way or the other , then you try to stop that motor from turning by holding onto the vise grips and mentally compare the force needed to turn the valve with the force needed to stop the motor.

Additionally there are other more accurate ways to measure the torque, like attaching a pully to the shaft
and having the motor lift a weight, (like a bucket you add or remove water from and then weigh the bucket. ) The converse of this is attach a pulley to the shaft of the valve and measure the weight of the amount of water needed to open and close the valve and then see if the motor can lift that amount of water (or sand, or rocks, or diamonds, or coins etc)
At the end of the day, you don't need to know the torque spec in Nm. All you need to do is find a motor that is capable of performing the required task and then look at the spec sheet for that motor and whatever it is , it exceeds the torque spec for you task.

raschemmel:
To a certain extent, some of the information can be obtain by simple manual testing.
Example, you have a valve that has a shaft. You clamp a pair of vise grips on the shaft and open and
close the valve by hand. Then you remove the visegrips from the valve and clamp on the motor shaft and turn on the motor and tell it to turn (slowly) one way or the other , then you try to stop that motor from turning by holding onto the vise grips and mentally compare the force needed to turn the valve with the force needed to stop the motor.

Additionally there are other more accurate ways to measure the torque, like attaching a pully to the shaft
and having the motor lift a weight, (like a bucket you add or remove water from and then weigh the bucket. ) The converse of this is attach a pulley to the shaft of the valve and measure the weight of the amount of water needed to open and close the valve and then see if the motor can lift that amount of water (or sand, or rocks, or diamonds, or coins etc)
At the end of the day, you don't need to know the torque spec in Nm. All you need to do is find a motor that is capable of performing the required task and then look at the spec sheet for that motor and whatever it is , it exceeds the torque spec for you task.

Fish scale?

birddseedd, when will you stop opening threads in the forum before you have figured out what you want?

You want to control a valve both by hand and by a motor, right?

You didn't even use the word "valve" before your FIFTH post and another TEN answers from users that spent their time trying to help you.

couka:
birddseedd, when will you stop opening threads in the forum before you have figured out what you want?

You want to control a valve both by hand and by a motor, right?

You didn't even use the word "valve" before your FIFTH post and another TEN answers from users that spent their time trying to help you.

Thats because im not controlling the valve itaelf but the handle bars their attached to.

I am inclined to request/demand a drawing but I fear that probably doesn't exist either.

raschemmel:
I am inclined to request/demand a drawing but I fear that probably doesn't exist either.

I could just take pictures of it.

It' your dime.

birddseedd:
I could just take pictures of it.

33 replies in I'd say it's about time you start doing those things. Or do you really have the feeling you're getting anywhere with this thread? I for one don't.

wvmarle:
33 replies in I'd say it's about time you start doing those things. Or do you really have the feeling you're getting anywhere with this thread? I for one don't.

I'm learning. that's the point. I've also been dealing with an emergency c section. But i do have a grasp on what type of servo will allow me to read position with it being powered down. Of course, now that i'm starting to put all this together, i'm starting to question everything. pro's and con's to everything

raschemmel:
I am inclined to request/demand a drawing but I fear that probably doesn't exist either.







so. if i build a bracket allowing me to attach at one of the two bolts, i measured 10 lbs of force to go forward 3.5 inches over about 4 seconds and 15 lbs backward about 2.5 inches over about 2 seconds.

so i need to figure out what strength servo i can use to obtain this. i can put a lever on the shaft to get the throw i need, but that means a stronger servo will be needed at the short end of a lever.

I don't see that working witha motor.
That looks more like acuator application.