This is my first post here, so hello all. I really hope I can learn a lot from you guys.

I am trying to build a robotic arm to carry an object and put it inside of different boxes that are placed in different fixed locations.

I found a few robotic arms that can do it, but I am still trying to find the right motor for the job. I read a lot on-line about the different motors, but I am not sure which on to pick. Since the boxes are located in fixed places, the motors have to move in a precise way, so, according to my research, Servo motors are the ones I should use.

Since it is a low budget project (I am college student), I wasn't sure which motor to choose (there are a lot of servo motors out there). I found several Servo motors on-line, for example , Analog Feedback Servo, and I was wondering what is the best servo motor I can buy for a really low cost project? I think I can spend about 10-20$ per motor (I need 5 motors).

I already have an Rpi and I know that pin 18 is the PWM pin that controls the motor's precision movement, but before I purchase a PWM controller and additional motors I need to run some testing to find how precise the motor is.

By the way, how can I calculate the amount of weight the motor can handle?

Any ideas and information will be greatly appreciated.

Thank you

  • 1
    $\begingroup$ Don't rule out stepper motors for that application. A stepper has quantifiable and repeatable accuracy, whereas those model-airplane servos are all over the place in terms of both accuracy and repeatability. $\endgroup$ – Mark Jun 9 '16 at 23:42

The choice of motors is a trade off between cost/power/ease of implementation/etc. that only you can make. But hobby servos like you linked to are a common choice for low-cost, low-power, hobby arms.

Simple max-torque calculations for a robot arm are pretty straight forward. (This is a simple tutorial). But there are a few online calculators to help: [1], [2].

You might also benefit from this robot arm tutorial.


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