Printed Robotic Arm Pumps Up With Brushless Motors

April 8, 2025 by Tom Nardi 1 Comment

[JesseDarr] recently wrote in to tell us about their dynamic Arm for Robitc Mischief (dARM), a mostly 3D printed six degrees of freedom (6DOF) robotic arm that’s designed to be stronger and more capable than what we’ve seen so far from the DIY community.

The secret? Rather than using servos, dARM uses brushless DC (BLDC) motors paired with ODrive S1 controllers. He credits [James Bruton] and [Skyentific] (two names which regular Hackaday readers are likely familiar with) for introducing him to not only the ODrive controllers, but the robotics applications for BLDCs in the first place.

dARM uses eight ODrive controllers on a CAN bus, which ultimately connect up to a Raspberry Pi 4B with a RS485 CAN Hat. The controllers are connected to each other in a daisy chain using basic twisted pair wire, which simplifies the construction and maintenance of the modular arm.

As for the motors themselves, the arm uses three different types depending on where they are located, with three Eaglepower 8308 units for primary actuators, a pair of GB36-2 motors in the forearm, and finally a GM5208-24 for the gripper. Together, [JesseDarr] says the motors and gearboxes are strong enough to lift a 5 pound (2.2 kilogram) payload when extended in a horizontal position.

The project’s documentation includes assembly instructions for the printed parts, a complete Bill of Materials, and guidance on how to get the software environment setup on the Raspberry Pi. It’s not exactly a step-by-step manual, but it looks like there’s more than enough information here for anyone who’s serious about building a dARM for themselves.

If you’d like to start off by putting together something a bit easier, we’ve seen considerably less intimidating robotic arms that you might be interested in.

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Explore Neural Radiance Fields In Real-time, Even On A Phone

December 20, 2023 by Donald Papp 8 Comments

Neural Radiance Fields (NeRF) is a method of reconstructing complex 3D scenes from sparse 2D inputs, and the field has been growing by leaps and bounds. Viewing a reconstructed scene is still nontrivial, but there’s a new innovation on the block: SMERF is a browser-based method of enabling full 3D navigation of even large scenes, efficient enough to render in real time on phones and laptops.

Don’t miss the gallery of demos which will run on anything from powerful desktops to smartphones. Notable is the distinct lack of blurry, cloudy, or distorted areas which tend to appear in under-observed areas of a NeRF scene (such as indoor corners and ceilings). The technical paper explains SMERF’s approach in more detail.

NeRFs as a concept first hit the scene in 2020 and the rate of advancement has been simply astounding, especially compared to demos from just last year. Watch the short video summarizing SMERF below, and marvel at how it compares to other methods, some of which are themselves only months old.

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Haptick: The Strain Gauge Based 6DoF Controller

March 20, 2023 by Matthew Carlson 16 Comments

Six degrees of freedom (6DoF) controllers are used for manipulating an object in a CAD or 3d modeling program and are often called spacemice. You can twist it, push it, and even bop it. Most work with optical encoders, shining an LED through a slit to some form of photodetector on the other side. [Matthew Schubert] wanted to make his own spacemouse, but had some new ideas of how to go about it. His two-part project, dubbed haptic, focuses on measuring the forces, not the displacement.

He decided to try thick-film resistors as strain gauges and revisit load cells and proper strain gauges later. The actual structure quickly converged on the Stewart Platform, formed from three custom PCBs. A base to sit on, a knob for the top, and a middle board designed to take the strain with SMD resistors. A Teensy 3.2 talks to the ADS131M06 ADC and streams 4k samples per second to the host computer via serial. For prototyping, the calculations were done on the PC. Continue reading “Haptick: The Strain Gauge Based 6DoF Controller” →

Spaceballs Get Serialized

January 9, 2023 by Matthew Carlson 33 Comments

As much as we’d love a TV show version of the cult classic movie, we’re talking about a different kind of Spaceball. While there have been many iterations, [Evan] had a Spaceball built by a company known as Spacetec in 1991 and rebranded by HP. Being an older peripheral, he used the Orbotron 9001, a converter from RS232 serial to USB, to interface his Spaceball with modern devices.

The spaceball was one of the first 6 degrees of freedom controllers, useful for CAD and some games that supported it. It’s famous for being involved in the NASA Mars Pathfinder mission as it was used to control the Sojourner rover. In addition to the perfect orb, it also features eight handy buttons.

The Orbotron is a USB-capable microcontroller (Atmel SAMD21) designed to support the Spaceball 360, 4000, and 5000 series. Ultimately, after tinkering with the code to support the 2003 and 3003 Spaceballs, he had some reasonably usable with some rough edges. For example, acceleration curves still need tweaking, and going too fast can get you stuck. The downside was the rubber coating on the ball that had degraded over the years, making it horrendously sticky.

All the code changes are on GitHub. We’d love to see more spacemice integrated into things, like this ergonomic keyboard. Or even an open-source version of a spacemouse. After the break, we have a video of [Adafruit] showing a Spaceball 2003 working with a serial adapter.

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Mouse Enjoys Its Freedom

December 28, 2022 by Bryan Cockfield 29 Comments

Although it took a little while to standardize on the two-button-with-scroll-wheel setup, most computers have used a mouse or mouse-like device to point at objects on the screen since the 80s. But beyond the standard “point and click” features of the mouse, there have been very few ground-breaking innovations beyond creature comforts. At least, until the “Space Mushroom” mouse from [Shinsaku Hiura] hit our tips line.

This mouse throws away most of the features a typical mouse might have in favor of a joystick-like interface that gives it six degrees of freedom instead of the usual two — while still being about mouse-sized and held in the hand. It doesn’t even have a way of mapping motion directly to movements on the screen. Instead, it maps each degree of freedom to a similar movement of the mouse itself using these three joystick sensors physically linked together, with some underlying programming to translate each movement into the expected movement on the screen.

While this might not replace a standard mouse for every use case anytime soon, it does seem to have tremendous benefit in 3D modeling software, CAD, or anything where orienting a virtual object is the primary goal. Plus, since there’s no limit to the number of mice that can be attached to a computer (beyond USB limitations) this mouse could easily be used in conjunction with a normal mouse much like macro keyboards being used alongside traditional ones.

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DIY SpaceNavigator Brings The Freedom

November 9, 2022 by Jonathan Bennett 25 Comments

[Pepijn de Vos] wanted a 6DOF HID. You know, a 6 Degrees Of Freedom Hardware Interface Device. Those are the fancy controllers for navigating in 3D space, for uses like Computer Aided Design, or Kerbal Space Program. And while we can’t speak to [Pepijn]’s KSP addiction, we do know that the commercially available controllers are prohibitively expensive. It takes some serious CAD work to justify the expenditure. [Pepijn] falls somewhere in-between, and while he couldn’t justify the expense, he does have the chops to design and 3D print his own.

Marvelously, he’s shared the design files for SpaceFox, linked above. It’s 6 spring-loaded potentiometers, supporting a floating printed Big Knob. The pots feed into an Arduino Pro Micro, which calculates the knob’s position on the fly and feeds in into the connected computer. On the computer side, the project uses the spacenavd driver to interface with various applications.

SpaceFox V1 is essentially a proof of concept, just asking for someone to come along and knock off the rough edges. [Pepijn] even includes a wishlist of improvements, but with the caveat that he’s satisfied with his working model. If this project really gets your 6DOF juices flowing, maybe try making an improved version, and share the improvements. And let us know about it!

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Six Degrees Of Freedom Omnicopter With Ardupilot

January 9, 2021 by Danie Conradie 12 Comments

Modern multirotors are very maneuverable but are mostly limited to hovering in a single orientation. [Peter Hall] has gotten around this by building an omnicopter drone with six motors mounted in different orientations on a collapsed tetrahedron frame.

The shape of the frame consists of six tetrahedrons all joined together at a single point. With a motor in each frame, the drone can produce a thrust vector in any direction, to achieve six degrees of freedom. The control system is the challenging part of this project, but fortunately [Peter] is one of the Ardupilot developers. Unlike a standard multirotor, it doesn’t need to tilt to move around laterally but can keep its orientation constant. One of the limiting factors is that the motors need to stop and reverse rotation for direction changes, which takes time. At slow maneuvering speeds this isn’t a major problem, but at higher speeds rotation is noticeably less smooth.

Because the drone is symmetrical all around, keeping track of orientation is challenging for a human pilot, but it’s perfect for an autopilot system like Ardupilot. In the video after the break, [Peter] demonstrates this by flying the drone around while the autopilot rotates it randomly. The 6DoF control system is open source and a pull request is live to integrate it into the official version of Ardupilot. The obvious application for this sort of drone is for inspection in and around structures.

This omnicopter is an entry into the Lynchpin drone competition by the celebrity [Terrence Howard]. We’re not quite following his claims regarding the scientific significance of this shape, which he named the “Lynchpin”, but it works for drones. Continue reading “Six Degrees Of Freedom Omnicopter With Ardupilot” →