Litter Buggies Haul Trash Off The Beach

July 5, 2021 by Danie Conradie 28 Comments

There is a depressing amount of trash in our oceans, and a lot of it is washes up on beaches. [Glenn Morris] has turned collecting all this trash into a favourite pastime, using a series of custom radio-controlled Litter Buggies to haul the load.

The most basic versions of these buggies are off the shelf RC rock crawlers, usually a Traxxas TRX-4, with a basket mounted in place of the body. However, [Glenn] has developed the buggies far beyond that, making extensive use of 3D printing to create purpose-built trash haulers. He has created several frame systems to hold removable baskets, buckets, lights and tools. Most of the buggies use lithium power tool batteries to allow quick swapping, and the electric motors, ESCs and gearing is selected for low speed and high torque. Since the buggies spend a lot of time exposed to salt water, almost all the steel hardware on the chassis are replaced with stainless steel. To allow for one handed control, [Glenn] attached 3D printed levers to the steering knobs of the standard RC controllers, allowing steering to be done with his thumb.

We really like what [Glenn] has been doing with these buggies, and think they might be a good platforms for adding some autonomous capabilities. Add a smartphone for target following or obstacle avoidance, or some solar panels and a GPS autopilot system.

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A Robot To Top Up Your Tesla

July 2, 2021 by Danie Conradie 37 Comments

The convenience of just plugging in your car in the evening and not going into a gas station is great as long as you remember to do the plugging. You really don’t want to get caught with an empty battery while you’re in a rush. [Pat Larson]’s Tesla plugging robot might be a handy insurance policy if you count forgetfulness among your weaknesses.

The robot consists of a standard Tesla charging plug attached to a 2-axis robotic arm mounted on [Pat]’s garage wall. Everything is controlled by a Python script running on Raspberry Pi 4. After taking a picture with a camera module, it uses a Tensor Flow Lite machine learning model to determine the position of a reflector on the charging port cover. The platform moves back and forth to align with the charging port, after which it opens the charging port using the Tesla API. It then extends the arm towards the charging port, using ultrasonic proximity sensors for distance control, and again uses the camera module and Tensor Flow to look for the illuminated Tesla logo adjacent to the charging port. The charge plug is flipped out using a large servo, and after some final position adjustment, it takes the plunge. While robot won’t be winning any interior design contests, it does the job well, and adds a bit of convenience and peace of mind.

Other Tesla hacks we’ve seen include building a working Model S for $6500, turning an old Honda into a speed demon using Tesla parts, and a Casio F-91W that can unlock your Tesla.

Robotic Ball-Bouncing Platform Learns New Tricks

June 30, 2021 by Donald Papp 11 Comments

[T-Kuhn]’s Octo-Bouncer platform has learned some new tricks since we saw it last. If you haven’t seen it before, this device uses computer vision from a camera mounted underneath its thick, clear acrylic platform to track a ball in 3D space, and make the necessary (and minute) adjustments needed to control the ball’s movements with a robotic platform in real time.

We loved the Octo-Bouncer’s mesmerizing action when we saw it last, and it’s only gotten better. Not only is there a whole new custom ball detection algorithm that [T-Kuhn] explains in detail, there are also now visualizations of both the ball’s position as well as the plate movements. There’s still one small mystery, however. Every now and again, [T-Kuhn] says that the ball will bounce in an unexpected direction. It doesn’t seem to be a bug related to the platform itself, but [T-Kuhn] has a suspicion. Since contact between the ball and platform is where all the control comes from, and the ball and platform touch only very little during a bounce, it’s possible that bits of dust (or perhaps even tiny imperfections on the ball’s surface itself) might be to blame. Regardless, it doesn’t detract from the device’s mesmerizing performance.

Design files and source code are available on the project’s GitHub repository for those who’d like a closer look. It’s pretty trippy watching the demonstration video because there is so much going on at once; you can check it out just below the page break.

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Ball CVT Drives Robot From A Constant Speed Motor

June 29, 2021 by Danie Conradie 13 Comments

[James Bruton] is experimenting is a series of interesting mechanical mechanisms, the latest being a CVT transmission system which uses a tilting sphere to get a variable speed output from a constant speed input. Video after the break.

In [James]’ proof of concept RC vehicle, a single powered disc is mounted on top, at 90 degree to the wheels. A rotating sphere makes contact with both the driven disc and the wheel. When the rotation axis of the sphere is at 45° between the disc and the wheel, it provides a one 1:1 transmission ratio. As the axis is tilted, the contact points on the sphere shift, changing the relative circumference at the contact points, and therefore changing the transmission ratio. It can also reverse by tilting the sphere in the opposite direction, and disconnected from the output wheel by aligning it with the hole in the bottom of the sphere. [James]’ simple two-wheel RC car concept quite well, driving around his kitchen with the transmission spheres being tilted by servos.

Thanks to the response time, CVT gearboxes are generally not needed for electric motors, but on internal combustion engines that which run best within a certain RPM range they can be very useful. One possible weak point of a design like this is it’s dependence on friction to transfer torque, which makes it vulnerable to wear and slipping.

This build is a spin-off of his spherical omni-wheels and the robot chassis he developed around them. For another interesting robot mechanism, check out is gyroscope balancing system. Continue reading “Ball CVT Drives Robot From A Constant Speed Motor” →

3D Printed Mecanum Wheels For Hoverboard Motors

June 25, 2021 by Tom Nardi 9 Comments

At this point, somebody taking the motors out of a cheap “hoverboard” and using them to power a scooter or remote controlled vehicle isn’t exactly a new idea. But in the case of the FPV rover [Proto G] has been working on, his choice of motors is only part of the story. The real interesting bit is the 3D printed omnidirectional Mecanum wheels he’s designed to fit the motors, which he thinks could have far reaching applications beyond his own project.

Now, that isn’t to say that the rover itself isn’t impressive. All of the laser cutting and sheet metal bending was done personally by [Proto G], and we love the elevated GoPro “turret” in the front that lets him look around while remotely driving the vehicle. Powered by a pair of Makita cordless tool batteries and utilizing hobby-grade RC parts, the rover looks like it would be a fantastic robotic platform to base further development on.

The Mecanum wheels themselves are two pieces, and make use of rollers pulled from far smaller commercially available wheels. This is perhaps not the most cost effective approach, but compared to the alternative of trying to print all the rollers, we see the advantage of using something off-the-shelf. If you’re not sure how to make these weird wheels work for you, [Proto G] has also released a video explaining how he mixes the RC channels to get the desired omnidirectional movement from the vehicle.

If you’re content with more traditional wheeled locomotion, we’ve previously seen how quickly a couple of second-hand hoverboards can be turned into a impressively powerful mobile platform for whatever diabolical plans you may have.

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Active Ball Joint Uses Spherical Gear

June 24, 2021 by Al Williams 40 Comments

A common CAD operation is to take a 2D shape and extrude it into a 3D shape. But what happens if you take a gear and replicate it along a sphere and then rotate it and do it again? As you can see in the video below, you wind up with a porcupine-like ball that you can transfer power to at nearly any angle. There’s a paper describing this spherical gear as part of an active ball joint mechanism and even if you aren’t mechanically inclined, it is something to see.

The spherical gear — technically a cross spherical gear — is made from PEEK and doesn’t look like it would be that difficult to fabricate. There’s also a simpler version known as a monopole gear in the drive system that provides three degrees of freedom.

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Scratch Built Tracked Robot Reporting For Duty

June 17, 2021 by Tom Nardi 18 Comments

Inspired by battle-hardened military robots, [Engineering Juice] wanted to build his own remote controlled rover that could deliver live video from the front lines. But rather than use an off-the-shelf tracked robot chassis, he decided to design and 3D print the whole thing from scratch. While the final product might not be bullet proof, it certainly doesn’t seem to have any trouble traveling through sand and other rough terrain.

Certainly the most impressive aspect of this project is the roller chain track and suspension system, which consists of more than 200 individual printed parts, fasteners, bearings, and linkages. Initially, [Engineering Juice] came up with a less complex suspension system for the robot, but unfortunately it had a tendency to bind up during testing. However the new and improved design, which uses four articulated wheels on each side, provides an impressive balance between speed and off-road capability.

Internally there’s a Raspberry Pi 4 paired with an L298 dual H-bridge controller board to drive the heavy duty gear motors. While the Pi is running off of a standard USB power bank, the drive motors are supplied by a custom 18650 battery pack utilizing a 3D printed frame to protect and secure the cells. A commercial night vision camera solution that connects to the Pi’s CSI header is mounted in the front, with live video being broadcast back to the operator over WiFi.

To actually control the bot, [Engineering Juice] has come up with a Node-RED GUI that’s well suited to a smartphone’s touch screen. Of course with all the power and flexibility of the Raspberry Pi, you could come up with whatever sort of control scheme you wanted. Or perhaps even go all in and make it autonomous. It looks like there’s still plenty of space inside the robot for additional hardware and sensors, so we’re interested to see where things go from here.

Got a rover project in mind that doesn’t need the all-terrain capability offered by tracks? A couple of used “hoverboards” can easily be commandeered to create a surprisingly powerful wheeled platform to use as a base.

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