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I've been looking for large robotic arms (with two fingers) and the arm so they are able to pick up and drop things in a space around the arm (and even spin around the 'wrist').

I'm not sure what the terminology is for such an arm. I've seen this, OWI-535 Robotic Arm Edge, and it looks close. Is there something larger that can be hooked up to a Raspberry Pi instead of the remote controller?

Is there a particular term for this in a generic context? Or is there a way to build such an arm using off the shelf parts?

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You might want to consider building, and designing (or following a standard design for) a robot arm, using "servo backets"1, which are designed to be used with standard servos (i.e., the MG995 or MG996R). Here is a common example of one such robot arm:

Robot arm using servo brackets

These brackets are cheap and widely available, as a quick search for servo brackets, or robot brackets will show you.

There are many types/forms/shapes available, and they are all compatible with each other:

  • Short U bracket;
  • Long U bracket;
  • Oblique U bracket;
  • I bracket;
  • L bracket
  • Multi Function bracket;
  • Body Plates;
  • Elongated, or Large, U bracket;
  • and others.

Note that these names are not standard, merely descriptive, and may vary from supplier to supplier. Here is a Short U and a Multi Function bracket

Short U and a Multi Function servo bracket

These brackets are reusable, so, once you have completed your robot arm, should you become tired of it, you could dismantle it, purchase some additional brackets and make a humanoid (upright) robot,

Humanoid 21 DOF robot using servo brackets

or a hexapod,

Hexapod using servo brackets

or whatever.

As the first photo (of the robot arm showed), a simple robot grabber/gripper is also available for the end of the arm:

Aluminium gripper

These grippers, and the brackets themselves, are widely available on eBay. Note that it is invariably cheaper to buy the brackets independently, than the whole arm kits that you see, by about 50% usually. Although having said that, the 21 DOF humanoid robot kits are actually the cheapest option, if you can get one for £45, and you think that you will need all of the extra brackets at some point in the future. You will also require bearings (and cups), so make sure that any kit that you buy has those included.

The parts that you will require for the robot arm are as follows:

  • Multifunctional bracket x 5
  • Long U shape bracket x 3
  • L shape bracket x 1 (to attach the claw)
  • Acrylic board x 1
  • Cup bearing x 4
  • Screw nut x September 1
  • Alloy mechanical claw x 1
  • U beam bracket x 2 (for the base)
  • MG996R x 6
  • Servo Extension cord x 3
  • Servo horns x 6

Here is a better view:

Arm robot


1 There is a correct name for them, other than servo brackets, but the real name escapes me.

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    $\begingroup$ Wow!, absolutely brilliant! I've been struggling with this question for months and I can't tell you how helpful this is. I wish I could thank you in a way more than a +1 $\endgroup$ – Akshat Mar 20 '16 at 7:24
  • $\begingroup$ @Akshat - You are welcome. You may find I, Robot useful as well. It is a little disorganised, but full of links and things on eBay that you might need. $\endgroup$ – Greenonline Mar 20 '16 at 7:33
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    $\begingroup$ Sounds good! I had a look at your blog & there are lots of good parts I see, I'm looking to make quite a big arm that can pick up wine bottles (with a square attachment on the bottle), before this can you believe I was looking at making the arm of wood?! If you need help on the programming end of things I'm quite helpful on the stackoverflow site $\endgroup$ – Akshat Mar 20 '16 at 7:49
  • $\begingroup$ I did a similar simulation using SolidWorks: youtube.com/watch?v=crJXUlzJ918 $\endgroup$ – LCarvalho Feb 19 '18 at 20:00
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The general name for the arm in your picture is an Articulated Arm or Articulated Robot but there are many variations on the theme.

I have mostly worked with SCARA arms as fewer motors need to hold the weight of the load:

enter image description here

See my answer to Which type of actuator will be suitable for a very strong robot arm

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  • $\begingroup$ I might use the rod type thing that lifts the arm. Do you know of where to get larger robot claws that are sturdier and can lift heavier things (like a 1l bottle of wine?) $\endgroup$ – Akshat Mar 21 '16 at 10:16

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