ZeroBug: From Simulation To Smooth Walking

July 21, 2021 by Danie Conradie 9 Comments

Thanks to 3D printing and cheap hobby servos, building you’re own small walking robot is not particularly difficult, but getting them to walk smoothly can be an entirely different story. Knowing this from experience, [Max.K] tackled the software side first by creating a virtual simulation of his ZeroBug hexapod, before building it.

Learning from his previous experience building a quadruped, ZeroBug started life in Processing as a simple stick figure, which gradually increased in complexity as [Max.K] figured out how to make it walk properly. He first developed the required movement sequence for the tip of each leg, and then added joints and calculated the actuator movements using reverse kinematics. Using the results of the simulations, he designed the mechanics and pulled it back into the simulation for final validation.

Each leg uses three micro servos which are controlled by an STM32F103 on a custom PCB, which handles all the motion calculations. It receives commands over UART from a python script running on a Raspberry Pi Zero. This allows for user control over a web interface using WiFi, or from a gamepad using a Bluetooth connection. [Max.K] also added a pincer to the front to allow it to interact with its environment. Video after the break.

The final product moves a lot smoother than most other servo-driven hexapods we’ve seen, and the entire project is well documented. The electronics and software are available on GitHub and the mechanics on Thingiverse.

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DIY Camera Dolly Costs More Time Than Money

July 19, 2021 by Donald Papp 14 Comments

A camera dolly can be fantastic filmmaking tool, and [Cornelius] was determined to create his own version: the “Dope” DIY Dolly. The result not only upped his production quality, but was also entirely in line with his DIY approach to filmmaking in general.

A basic dolly design is straightforward enough: a flat platform with wheels, and some aluminum tubing upon which to roll. But while dolly assemblies are easy to purchase or rent, [Cornelius] found that his DIY version — which used easily sourced parts and about 80 hours worth of 3D printing — provided perfectly acceptable results, while opening the door to remixing and sharing with like-minded filmmakers.

Interested? Download the STL files to get started on your own version. As for the track, smooth metal pipe is best, but sometimes track made from PVC can do the job. [Cornelius] has a few additional STL files for those planning to make a base from 1″ PVC pipe, and those are on a separate download link near the bottom of the project page (here’s that link again.) Watch the Dope Dolly in action in the brief video embedded below.

On the other hand, if you prefer your DIY camera equipment to be on the smaller and more complicated end of the spectrum, be sure to check out this multi-axis camera slider.

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Big 3D-Printed Lamp Tries Some New Features

July 14, 2021 by Donald Papp 10 Comments

In lamp design, bulbs are usually given generous clearances because they get hot during use. LED bulbs however give off comparatively little heat, which opens a few new doors. [Mark Rehorst] created this huge 3D printed lamp, made with his custom 3D printer and a hefty 1 mm diameter nozzle, and the resulting device not only looks great, but shows off a few neat design features.

The LED filament bulb doesn’t give off much heat, so a PETG partial shade mounted directly to the bulb works fine.

[Mark] printed a partial shade in PETG that is made to sit directly on the bulb itself. The back of the shade is open, allowing light to spill out from behind while the front of the bulb is shielded, making it easier on the eyes. The result is pretty nifty, as you can see here. It sits in the center of the 600 mm tall lamp, which takes up most of the build volume of his self-made CoreXY-based printer, the UMMD.

The LED filament strands in this style of bulb are pretty neat in their own way, and some of you may remember that when they first became available as separate components, no time was lost in finding out what made them tick.

Extreme Canine Mask For Protection From Foxtails

July 4, 2021 by Danie Conradie 33 Comments

Our canine partners are fortunately not affected by the current global pandemic, but it turns out there are other dangers that might necessitate them to wearing masks: Foxtail seeds. After getting a $400 vet bill for extracting a foxtail from his dog, [Hildeguard]’s ear, [Amos Dudley] decided to take the threat seriously and made her a form-fitting 3D printed mask.

The only commercial solution [Amos] could find was the “OutFox Field Guard”, which is a $50 vinyl-coated mesh bag that covers the dog’s entire head. It had the unfortunate side effects of causing some other dogs to try and rip it off and does not allow easy access to the mouth for treats or balls. [Hilde]’s custom mask was designed in CAD after creating a rough 3D scan of her head with an iPhone app. The bottom is open to allow [Hilde] to freely use her mouth, while the nose and ears holes are covered with mesh. Custom heat-formed polycarbonate lenses cover the eye holes. The mask itself was printed using Draft resin, and the inside was padded with a thin layer of foam. It might also be possible to create a silicone version using a 3D-printed mold. The top features an integrated GoPro mount, and we can’t help but wonder what other electronic upgrades could be fitted to this sci-fi-looking mask.

In the field, the mask worked well and did not seem to bother [Hilde]. Unfortunately, it did not solve the problem of other dogs trying to rip it off at the park, so for the moment [Amos] is only using it for more solitary activities like hiking.

It doesn’t look like [Amos] is struggling in that department, but if you need some help burning of your dog’s energy, you can always built them a 3D printed automatic ball launcher.

PinThing Mechanizes Pin Art

June 30, 2021 by Danie Conradie 11 Comments

Pin art is one of those things that simply cannot be left alone if it’s within arms reach, and inevitably end up with a hand or face imprint. [hugs] is also fascinated by them, so he designed the PinThing, a mechanized pin art display.

The PinThing pin diameters are much larger than standard pin art, but this is to fit small geared DC motors. Each pin is a short 3D-printed lead screw mechanism. The motors are driven with a stack of motor driver shields on top of an Arduino Uno, which uses Firmata to receive instructions over serial from a Node.js app using the Johnny-Five library. This may be a simple 3×5 proof of concept, but then it could be used for everything from displays to interactive table surfaces.

One of the challenges with pixelated mechanical displays like this, the inFORM from MIT, or even flip dot displays, are the costs in actuators and driver electronics. A small 10×10 array requires 100 motors and drivers, which quickly adds up as you expand, even if individual components are quite cheap.

If you are willing to sacrifice instantaneous response from each pixel, you can use a mechanical multiplexer. It consists of some sort of moving carriage behind the display with mounted actuators, so you’ll only need an actuator per row, not for every pin. This also means the pins can be closer together since the actuators can be staggered on the carriage.

PinThing project was an entry to the Rethink Displays Challenge of the 2021 Hackaday Prize, for which the finalists were just announced.

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Mechanical 7-Segment Display Uses A Single Motor

June 27, 2021 by Danie Conradie 29 Comments

Seven-segment displays have been around for a long time, and there is a seemingly endless number of ways to build them. The latest of is a mechanical seven-segment from a master of 3D printed mechanisms, [gzumwalt], and can use a single motor to cycle through all ten possible numbers.

The trick lies in a synchronized pair of rotating discs, one for the top four segments and another for the bottom three segments. Each disc has a series of concentric cam slots to drive followers that flip the red segments in and out of view. The display can cycle through all ten states in a single rotation of the discs, so the cam paths are divided in 36° increments. [gzumwalt] has shown us a completed physical version, but judging by CAD design and working prototype of a single segment, we are pretty confident it will. While it’s not shown in the design, we suspect it will be driven by a stepper motors and synchronized with a belt or intermediate gear.

Another 3D printed mechanical display we’ve seen recently is a DIY flip dot, array, which uses the same electromagnet system as the commercial versions. [gzumwalt] has a gift for designing fascinating mechanical automatons around a single motor, including an edge avoiding robot and a magnetic fridge crawler.

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Mechanically Multiplexed Flip-Dot

June 24, 2021 by Danie Conradie 11 Comments

Flip dots displays are timeless classics, but driving the large ones can quickly turn into a major challenge. The electromagnets require a lot of current to operate, and the driver circuits can get quite expensive. [James Bruton] wanted to build his own, but followed a bit of a different route, building a mechanically multiplexed flip dot (ball?) display.

Each of the dots on [James]’ 5×3 proof of concept is a bistable mechanical mechanism that can either show or hide a ping pong ball sized half sphere. Instead of using electromagnets, the dots are flipped by a row of micro servos mounted on a moving carriage behind the display. The mechanism is derived from one of [James]’ previous projects, a mechanical multiplexer. Each dot mechanism has a hook at the back of the mechanism for a servo to push or pull to flip the dot. A major disadvantage of this design is the fact that the servo horn must match the state of the dot before moving through the hook, otherwise it can crash and break something, which also reduces the speed at which the carriage can move.

This build was just to get a feel for the concept, and [James] already has several ideas for changes and improvements. The hook design can certainly change, and a belt drive would really speed things up. We think this mechanical display is a very interesting design challenge, and we are interested to hear how our readers would tackle it? Let us know in the comments below.

Recently we covered a 3D printed flip dot display for the first time. It’s still small and [Larry Builds] is working out the kinks, but we would love to see it eventually match the mesmerising effect of Breakfast’s large installations.