How to check if servo is strong enough

Hi all,

Very new to all the robotics and not at ease with electronics, I decided to start a small project and learn some stuff.
I would like to rotate a screen, from “portrait” to “landscape”, using a servo motor.
From what I understood, I would need a servo motor as well as a controller, and a wheel.
I would like the screen to be on a MDF panel (that I would cut to remove all the ‘unecessary’ space, so it might not be square, thus lighter).

The constraints are the following:

  • I would like to use USB only to power that. Is it possible ?
  • I don’t know nothing (jon snow, sorry, joke) about torque calculation and stuff like that, but I would like to not ‘overuse’ the motor, therefore, how to know what kind of motor to use?
  • I don’t really care about the speed or time to make the rotation, as long as it is not more that few seconds (let’s say 2seconds ?)
  • I have 2 microswitches that I can use for stop limits (but not idea on how to use them here…)
  • ideally, I would like the whole thing to be controllable via a pc (i.e. I send a command, from DOS or any, and the screen rotates)

and finally, as I really know few about all that, I am not sure about all parts needed, so please, could you help me on that, as deep as a complete part list ?
I searched on the forum but could not find something for beginners, nor with close up pictures of the wiring, coding etc…

I saw that

will this be sufficient ? (for an example of ‘complete part list’ that I mentionned earlier, I would need a usb cable here for example, this one was easy, but for jumpers etc, I wouldn’t know which/what to choose)

I would just connect the servo to channel 0 (and channel 1 if I have another servo for something else), then use the Maestro Servo Controller Windows Drivers and Software (release 130422) and that’s all ? will I have enough power ?

Is it sufficient for my screen ? let’s say it weights 4-5kg (with MDF).

Thanks a LOT for any help :slight_smile:

By “MDF” do you mean Medium Density Fiberboard?

With appropriate bearings that take all the weight, you might be able to rotate a 4-5 kg load. But that would depend on your mechanical design and construction skills.

Pololu has a nice tutorial on force and torque here: It is essential that you understand the material if you expect to make headway on this project.

Hi Jim

Thanks a lot for your answer.

Yes sorry, by MDF, I meant Medium Density Fiberboard. My skills are not good enough so consider that I would need to go with a configuration that has margin (not too much however, I don’t need to have my flat spinning, just a screen monitor :D).

I am reading the link now, very interesting. Trying to understand everything tho (I am not an english native speaker).

So, as I don’t want to risk it and burn my servos (I will use those ones for another project where I would turn a small wheel to change a joystick caracteristics from 4 to 8 directions, I think it will be enough), can I use that one : or still too risky ? will I be able to have that one (+ wheel and mounting hub), and three of the other ones on the same controller, and all via USB only ?

I saw somewhere that someone used that :

I can see that the gearmotor is far more powerfull (only by looking at it actually, not really getting the specs yet), but I don’t understand the differences clearly, nor between the two controllers, besides the total price difference.

If this servo is not enough, I am sure there is something in between, right ?

and finally, I read somewhere also that it would be impossible to have my screen rotating only via USB 5v. is it true ?

Thanks again for any help, back to my reading !

[quote]I read somewhere also that it would be impossible to have my screen rotating only via USB 5v. is it true ?[/quote]No, not true. If properly supported the screen could be rotated very slowly, using very little power.

You need to build the mechanical part and measure the force/torque required to accomplish your goal, before you decide on a motor and gear arrangement.