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” →

Homebrew Linear Actuators Put The Moves On This Motion Simulator

October 4, 2018 by Dan Maloney 32 Comments

Breaking into the world of auto racing is easy. Step 1: Buy an expensive car. Step 2: Learn how to drive it without crashing. If you’re stuck at step 1, and things aren’t looking great for step 2 either, you might want to consider going with a virtual Porsche or Ferrari and spending your evenings driving virtual laps rather than real ones.

The trouble is, that can get a bit boring after a while, which is what this DIY motion simulator platform is meant to address. In a long series of posts with a load of build details, [pmvcda] goes through what he’s come up with so far on this work in progress. He’s building a Stewart platform, of the type we’ve seen before but on a much grander scale. This one will be large enough to hold a race car cockpit mockup, which explains the welded aluminum frame. We were most interested in the six custom-made linear actuators, though. Aluminum extrusions form the frame holding BLDC motor, and guide the nut of a long ball screw. There are a bunch of 3D-printed parts in the actuators, each of which is anchored to the frame and to the platform by simple universal joints. The actuators are a little on the loud side, but they’re fast and powerful, and they’ve got a great industrial look.

If car racing is not your thing and you’d rather build a full-motion flight simulator, here’s one that also uses DIY actuators.

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Stewart Platform Ball Bearing Balancer

August 22, 2014 by Edward Becker 23 Comments

For their Mechanical Engineering senior design project at San Jose State University, [Tyler Kroymann] and [Robert Dee] designed and built a racing motion simulator. Which is slightly out of the budget of most hackers, so before they went full-scale, a more affordable Arduino powered Stewart platform proof of concept was built. Stewart platforms typically use six electric or hydraulic linear actuators to provide motion in six degrees of freedom (6 DOF), surge (X), sway (Y), heave (Z), pitch, roll, and yaw. With a simple software translation matrix, to account for the angular displacement of the servo arm, you can transform the needed linear motions into PWM signals for standard hobby servos.

The 6 DOF platform, with the addition of a resistive touch screen, also doubled as a side project for their mechatronic control systems class. However, in this configuration the platform was constrained to just pitch and roll. The Arduino reads the resistive touch screen and registers the ball bearing’s location. Then a PID compares this to the target location generating an error vector. The error vector is used to find an inverse kinematic solution which causes the actuators to move the ball towards the target location. This whole process is repeated 50 times a second. The target location can be a pre-programmed or controlled using the analog stick on a Wii nunchuck.

Watch the ball bearing seek the target location after the break.

Thanks to [Toby] for sending in this tip.

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Tube Amp Monitor

June 23, 2008 by Juan Aguilar 5 Comments

Sparkfun contributor [Pete] really loves tube amps, but he’s a very safety-conscious guy who doesn’t like being electrocuted. This is a problem, since tube amps are usually very high voltage, and a small mistake can be fatal. To deal with this voltage issue, he built a tube amp with a control system built around a 6DOF v3 controller board. The control system is there mainly in case of a failure, automatically shutting off the high voltage transformer in any such event. It has the added benefit of filtering any 60Hz noise from getting into the audio, which happened before he installed the control system.

In addition to regulating power, the controller board also monitors bias points in the output tubes and displays its diagnostics on an LCD. Aside from getting great sound from the tube amp, [Pete] made it look great too, installing colored LEDs under the tubes. We love his design: just because safety comes first it doesn’t mean cool-factor can’t come in a close second.