Hacklet 30 – Robot Arm Projects

Robot arms – they do everything from moving silicon wafers to welding cars. Many a hacker has dreamt of having their own robot arm to serve them beer help them build projects. This week’s Hacklet features some of the best robot arm projects on Hackaday.io!

robotarm1We start with [4ndreas] who is building this incredible 3D Printable Robot Arm. Inspired by large industrial robots, [4ndreas] has given us an entirely 3D printable design. [4ndreas’] 3D design experience really shows here. This arm looks like it just finished work at a local assembly line! The arm is BIG too – printing the parts took him about a week, and used around 1.2kg of ABS filament! [4ndreas] has recently split the project off into two halves: his blue arm is driven by stepper motors, while the orange arm is a DC motor affair. Both of the arms can use his awesome gripper design. Check out the project page for videos of the arm in action!

6dofarmNext up is [Dan Royer] and his 6DOF Robot Arm. [Dan’s] didn’t want to spend upwards of $10,000 on an industrial arm, so he built his own from wood, plastic, and easily obtainable parts. As the name implies, the arm has 6 degrees of freedom. The electronics consist of beefy NEMA 17 stepper motors and a RUMBA controller, which was originally designed for 3D printers. Dan even created some novel encoder mounts. Each joint has an encoder, which will allow the robot to run as a closed loop system. [Dan] originally entered this arm in The Hackaday Prize 2014. While it didn’t get him to space, we’re betting it will be able to get him a soda!


No robot arm Hacklet would be complete without featuring [ben.phenoptix] and the awesome MeArm. MeArm is a pocket-sized robot arm which uses tiny 9 gram servos for locomotion. It’s built from laser cut acrylic and standard hardware. We loved the MeArm so much that we featured it as one of the challenges in our Embedded Hardware Workshop in Munich. More recently, [Ben] and MeArm have had a great run on Kickstarter. Let’s hope those arms are good at stuffing, addressing, and mailing out packages!


owiFinally we have [Kenji Larsen] with Reactron material transporter. The material transporter is just a small part of [Kenji’s] larger Reactron project. It started with an OWI-535 robot arm. The OWI is really a toy – a plastic kit which builds an open loop DC motor driven arm. [Kenji] has put some serious time into modifying his particular arm. He experimented with molding his own potentiometers for each joint before settling on a printed circuit board based design. Once the new system was in place, he found that his resistors were good for about 10,000 cycles. Not bad for a modified toy!

There are quite a few robot arm projects we weren’t able to cover in this edition of The Hacklet – you can check them all out on our brand new Robot Arm Projects List!

That’s it for this Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Reverse Engineering a Robotic Arm

Not too many people will argue that Robot Arms aren’t cool. [Dan] thinks they are cool and purchased a LabVolt Armdroid robotic arm on eBay for a mere $150. Unfortunately, he did not get the power supply or the control unit. To most, this would a serious hurdle to overcome, but not for [Dan]. He opened up the robot and started probing around the circuit board to figure out what was going on.

Since there was a DB9 connector on the outside of the robot arm, he assumed it was a standard RS-232 controlled device. Good thing he checked the internal circuitry because this was not the case at all. There was no mircocontroller or microprocessor found inside.  [Dan] painstakingly reversed engineered the circuit board and documented his results. He found that there were SN76537A chips that drove the 6 unipolar stepper motors and SN75HC259 latches to address each individual motor.

Now knowing how the robot works, [Dan] had to figure out how to control the robot from his computer. He started by making a custom Parallel Port to DB9 cable to connect the computer to the arm. After a series of several programs, starting with simply moving just one arm joint, the latest iteration allows manual control of all joints using the computer keyboard. A big ‘Thanks’ goes out to [Dan] for all his work and documentation.


Robot Arm You Can Build At Home

[jjshortcut] has created an easy to make robot arm that has 6 degrees of freedom. There is not much to it, the frame is made out of 4mm thick hardboard, hobby servos provide the power and a handful of hardware holds it together. The frame has been successfully cut out on both a laser cutter and a cnc router, making this design even more obtainable for any aspiring roboticist.

To control the robot arms movements [jjshortcut] plans to use a standard Arduino. There are certainly plenty of servo motor shields available but he still decided to design his own. In addition to the standard motor power and servo connections, a header for an infrared receiver was added for potential future communication options.

DIY Robot Arm GripperLike any project, there were some hiccups along the way. First, several revisions of the gripper were necessary to get the correct tooth profile that resulted in smooth and tight movement. Also, while making the shield the spacing between banks of headers came out one header too close! On this first board [jjshortcut] just bent the pins so they would fit into the Arduino. You can’t let some minor snafu prevent forward momentum of a project!

[jjshortcut] has done the hard part; the design. He has made all his mechanical and electronic files available… so go and build one! Check out the video after the break.

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The Triple Delta Robot Arm (and Leg)

delta By now you’d think we’ve seen just about every means of robotic actuator possible. We have Cartesian bots, Stewart platforms, SCARA bots, Delta bots, and even some exceedingly bizarre linkages from [Nicholas Seward]. We’re not done with odd robotic arms, it seems, and now we have Delta-ish robots that can move outside their minimum enclosed volume. They’re fresh from the workshop of [Aad van der Geest], and he’s calling them double and triple Deltas.

Previous Delta robots have used three universal joints to move the end effector up and down, and side to side. They’re extremely fast and are a great design for 3D printers and pick and place machines, but they do have a limitation: the tip of a single Delta can not move much further than the base of the robot.

By adding more parallelograms to a Delta, [Aad] greatly increases working volume of a his robots. One of the suggested uses for this style of bot is for palletizers, demonstrated in the video below by stacking Jenga blocks. There is another very interesting application: legs. There’s footage of a small, simple triple Delta scooting around the floor, supported by wire training wheels below. It makes a good cat toy, but we’d love to see a bipedal robot with this style of legs.

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Watch Out Artists, Robots Take Your Job Next

Move over Claude Monet, there is a new act in town in the form of a robot capable of creating some pretty cool art.

We’ve seen robotic artists before but most of them are either cartesian-based or hanging drawbots. This is a full-fledged Sharpie-wielding robotic arm that draws with dots giving its work an impressionistic feel.

The actual robotic arm is a stock Interbotix WidowX. The folks over at Phantom Multimedia wrote some custom software that takes a graphic and breaks it down into a 1-bit representation. The code then goes through the bitmap at random, picking points to draw on the medium. The hard part of this project was figuring out how to translate the 2D image into 3D robotic arm movements. Since the arm has several joints, there are multiple mathematical solutions for arm position to move the marker to any given point. The team ended up writing an algorithm to determine the most efficient way to move from point to point. Even so, each drawing takes hours.

As if that wasn’t enough, the software was then reworked to probe positions. Instead of automatically moving the arm to a predetermined point, the arm is manually moved to a location and the data retrieved from the servo encoders is used to determine the position of a probe at the end of the arm. Each point taken in this manner can then be combined to generate a 3D model.

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Retrotechtacular: 6CH industrial robot


With this robotic arm demo video from 1975 the future really is now. Think about it, there are entire factories full of the descendants of this technology where the human workers simply feed the beast and fix it when it breaks.

We’re pretty impressed by what’s shown off below. Not because we see something we didn’t know was possible, but because the technology was so advanced nearly forty years ago. Here the arm is laying out a wiring harness on a jig. We wonder if using a single color of wire is going to make it a major pain when they add the connectors?

Obviously the mechanics were solid. Time has brought further advances in precision, reduced costs that make robots available for even small factories (often palletizing products is done by a machine similar to this), and improvements in how tasks are programmed. After all, the ability to print a hard copy of the program as a punch tape isn’t quite cutting edge for this decade.

What does that mean for you? If you look hard enough you might be able to find an older generation robot arm to hack on.

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