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uArm - Desktop Robotic Arm

The uArm is an Arduino-powered, 4-axis robot arm that has been modeled after industrial pallet packing and car building robots which can be set up and used straight off of your desktop. Each uArm is equipped with three digital servos at the base to control the basic movement of the arm and an additional mini servo attached to the end-effector that moves and rotates the object you are lifting with your chosen manipulator. We all know how much of a pain building robotic equipment can be, that's why we have made sure to provide you with fully assembled versions of this robotic arm. All you need to do to physically set it up is attach it to your desk or other work area with the four provided suction cups at the arm's base (or screw it down for more permanent uses) and you are set to start using it.

So what's all included with the uArm desktop robotic arm, anyway? With each order you will receive one fully assembled metal body uArm (with servos already attached), one "uDuino" Arduino compatible board, one uArm shield, a vacuum gripper system (this includes the suction cup end-effector assembly, vacuum pump, and solenoid valve), one phillips head screw driver for maintenance, and a USB and wall adapter power supply. While the Arduino com,patible board is essentially just that, the uArm shield not only serves as a gate way to control the uArm itself it also features a "Learning Mode" that provides the means to record and replay manually assigned movement you dictated to the robot arm. Simply press the "Record" button on the uArm shield, physically move the arm as you desire, and then end the recording.

The vacuum gripper system included with the uArm is driven by a 5V air vacuum pump and valve, and is capable of lifting and holding about 1 kg of weight. The end-effector suction cup can pick up most objects with a smooth exterior within the aforementioned weight limit. Since the uArm utilizes a parallel-mechanism system, the end-effector of the arm will always be kept parallel to its base. The uArm is a truly fantastic robotic arm kit that can be used in a wide variety of applications to help teach basic to advanced robotics. We've personally used it as an automatic card dealer for our merciless Go Fish tournament, but the uses for the uArm are endless.


  • 1x uArm - Desktop Robotic Arm (fully assembled)
  • 1x USB-B to USB-A Cable
  • 1x Wall Adapter Power Supply
  • 1x Phillips Head Screw Driver
  • Fully Assembled
  • 4-Axis Parallel-Mechanism
  • Arm Reach: 70-340mm
  • Working Range: 180°
  • Vacuum Gripper System Included
  • Resilient Aluminum Body
  • 1kg Weight Suction Weight Limit
  • Manual Record Function

uArm - Desktop Robotic Arm Product Help and Resources

Core Skill: Robotics

This skill concerns mechanical and robotics knowledge. You may need to know how mechanical parts interact, how motors work, or how to use motor drivers and controllers.

2 Robotics

Skill Level: Rookie - You will be required to know some basics about motors, basic motor drivers and how simple robotic motion can be accomplished.
See all skill levels

Core Skill: DIY

Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.


Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
See all skill levels

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
See all skill levels

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #928140 / about 7 years ago / 1

    Does anyone know the thickness of uarm's parts,because i'm not sure ,i note that uarm's parts have a different thickness ??? thanks for answering me.

  • Hackberry Jake / about 9 years ago / 4

    Assembly is the funnest part!

  • Mr Electrical / about 9 years ago * / 3

    It's interesting that you guys are selling fully assembled units. The reason folks buy stuff from Sparkfun is that they are looking to make things; common sense would say that a majority of folks would want to assemble something like this as well. The main benefit of buying something like this instead of making everything from scratch (beyond convenience) is that most folks don't have the correct machinery or workshops to do it themselves.

    I would very much like to see (and would VERY likely buy) an unassembled kit that included good servos for a decent price. The current $400 price point is a bit much - if you cut the costs of assembly and just shipped a box of parts, you could sell it for $200-$250 and likely get a few more folks to buy it. I could very easily order/commission all of these parts for around $150 end cost from local sources (ie, non-bulk/non-ebay pricing) - the $400 price tag just seems a bit much to save a bit of errand running.

    The more folks that purchase it, the more feedback you will get, the better the product becomes, the MORE folks purchase it.....the cycle goes on and on. I'd love to see robotic arms take off like RepRap and 3D printers have. But, the only way to do that is to make things accessible at a software level AND at a price point.

    One more thing that the uArm Team might consider are geared DC motors with small encoders in place of hobby servos. The end cost is going to be about the same, but you are able to tailor your acceleration curves (WOOT PID LOOPS!) much more easily to reduce backlash and your precision and repeatability increases dramatically. Hobby servos are easy, but not great for larger robotic systems.

    Edit - Somehow, I missed the picture with the unit next to the $2 bill. There is SERIOUSLY no reason this should cost $400. There is also no reason it needs to be made out of aluminum for something this small. Acrylic would work just as well. Don't get me wrong, the aluminum is nice, but a bit overkill structurally speaking. A well programmed acceleration curve would nix vibrations out the window.

    • phenoptix / about 9 years ago / 1

      So you'd want a robot arm kit, at a lower price point, possibly made from acrylic? I have to say I like your style!

    • Thanks for your advice! We can't agree more about selling the unassembled kits. But what we think over is the difficulty of the assembling. The previous acrylic version needs almost 5-6 hours to do the assembling and during the assembling we also find many steps which are difficult for people to access. So we do want to make some parts together and make the assembling easier, and that's the real reason why we change the materiel to the aluminum. Now it only needs less than 2 hours to make it, but there are still some steps which are not easy enough and we are trying to improve it. We will provide the unassembled kit as soon as we get everything ready. What's more, we are always keeping trying to provide our consumers the cheapest products with the best quality. Currently the quantity is not large enough, so it indeed cost us more to get the parts with best quality. Anyway, now we have several engineers who are good at these and trying to improve it. We are sure that we can offer better products with lower price in the future. Many thanks for your advice and we will try to do our best as always.

  • Member #525619 / about 9 years ago / 3

    I've seen this in action on EEVBlog. The accuracy is necessarily lousy -- determined by your PCM resolution and the quality of the servos. The worst engineering miss on there was the connectivity -- the USB and power plug into the electronics "carriage" and whip around your workbench.

    I see no more than $100 in parts there, so the price is ludicrous. It was bad enough on their kickstarter, but this is seriously deranged.

    • Thanks very much for your advice. There is no doubt that the precision of uArm is not good or even worse compared with the industry robot arm. And also the performance of the servos is not the best in the market. But the point is that industry robot and uArm are two different things. Although accuracy is not the most primary appeal in uArm, we also do a lot of work to improve it (decreasing the backlash in the gearings, using cnc to cut the holes and etc.). For our target customers we think , the easier to control, the better, and the more funny to play with it , the better. So we develop the mouse control, leapmotion control and learning model for the uArm and all of them are very easy to use and bring people a lot of fun. As it is known that every coin has two sides. Although the tail with the electronics can make the wires whip on the desk, but when uArm lifts something heavy in the end-effector the tail will play a very important role in keeping the balance of the uArm. Thanks for your advice again and it means a lot to us! If you have any other suggestions, please feel free to let us know. Thanks!

      • Member #525619 / about 9 years ago * / 2

        Suggestion: Price it at $99. That's still a bit much for a toy, but such as the nature of these DIY robotics. $399 is simply silly for a toy. I could see $199 or $249 if it used stepper motors with a positional accuracy closer to 1mm.

        • Thanks for your advice. Pricing a product, we need to consider many different aspects, including cost on manufacturing, structure, materials, labor, operation, marketing..etc. Also the quantity is an important factor in affecting the cost and this will affect the price of product. The price is fixed based on these after serious consideration. For the stepper motors, we are doing the test about it. We are also trying to lower the cost and price. Thanks!

  • Member #539573 / about 9 years ago / 2

    Does anyone know the positional accuracy of this arm? Thanks.

  • iandees / about 9 years ago / 2

    I bought one of these on Kickstarter and they shipped bad servos. I've tried to reach the supplier via their support channels to no avail. Does Sparkfun have any replacement parts for this robot or are you just selling the arm kit?

    • We don't have any replacement parts, but we stand behind what we sell. If you have an issue with a product bought from us, we'll take care of you.

      • iandees / about 9 years ago / 1

        I should have waited and bought it from you guys ;).

    • Really sorry for the inconvenience! Please send your address and phone number to, and we'll send you the servos for replacement.

  • Member #474258 / about 9 years ago / 1

    Will the metalwork be sold separately? I'd like the option of incorporating the electronics myself-

  • JopieK / about 9 years ago / 1

    If it could be a bit more precise one could maybe use it for DIY PNP applications.

  • Member #342551 / about 9 years ago / 1

    will you sell the arm alone?? (no electronics)

  • Member #496749 / about 9 years ago / 1

    I was thinking, and I think that you could implement the coffee gripper ( has a good example). But my question is whether the pneumatic systems are compatible with it? If it was, then you could switch to grabbing objects that aren't flat.

  • Member #658289 / about 9 years ago / 1

    can you buy a mechanical end-effector (gripper) also? can you vary the amount of suction

  • Member #658289 / about 9 years ago / 1

    Hi sparkfun robertc etc, the reason i will buy from you is the support. appreciated, there's always glitcches, problems..

  • Nunzio / about 9 years ago / 1

    How Arduino is capable to understand and reverse record and play servo positions while they are detached?

    • Here's an explanation.

    • You can add a feedback wire to any servo easy as. Inside there is a potentiometer, turned as the servo moves. Just connect the middle pin on the pot to your analogue in. Generally the pin will vary between 0 & 5v over the servos range of movement.

      I suspect the 'feedback' servos are just off the shelf servos with the wire added. Making your own means you can use servos of an appropriate size / torque.

    • ThomasCouey / about 9 years ago * / 1

      PickledDog is right about the feedback wire.

    • PickledDog / about 9 years ago / 1

      I see these servos have a 4th wire which, from reading the code, is hooked to an analog pin. These must be "analog feedback" servos. In this case, the 4th wire is connected to the internal feedback pot, allowing you to read the servo's position with analogRead.

    • Despite I laughed a lot of Robert's answer, this is one way to do it!

  • Member #19855 / about 9 years ago / 1

    Is the electronics chassis really held up in the air? Or am I just getting tricked by the photography angles lol. If it is, I wonder if it's just for aesthetics or serves as a counterbalance of some sort.

    • DonW / about 9 years ago / 1

      Sure looks like that in photo 3, the side view. I imagine it's both for counterbalance when the arm is extended and to insure a constant range of motion for the cables & vac tube.

    • MatthewR / about 9 years ago * / 0

      (*edit: what DonW said)

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