Leap Motion Controls Hands With No Glove

May 8, 2021 by Al Williams No comments

It isn’t uncommon to see a robot hand-controlled with a glove to mimic a user’s motion. [All Parts Combined] has a different method. Using a Leap Motion controller, he can record hand motions with no glove and then play them back to the robot hand at will. You can see the project in the video, below.

The project seems straightforward enough, but apparently, the Leap documentation isn’t the best. Since he worked it out, though, you might find the code useful.

An 8266 runs everything, although you could probably get by with less. The Leap provides more data than the hand has servos, so there was a bit of algorithm development.

We picked up a few tips about building flexible fingers using heated vinyl tubing. Never know when that’s going to come in handy — no pun intended. The cardboard construction isn’t going to be pretty, but a glove cover works well. You could probably 3D print something, too.

The Unity app will drive the hand live or can playback one of the five recorded routines. You can see how the record and playback work on the video.

This reminded us of another robot hand project, this one 3D printed. We’ve seen more traditional robot arms moving with a Leap before, too. Continue reading “Leap Motion Controls Hands With No Glove” →

Auto Ball Launcher Will Be Your Dog’s New Best Friend

April 21, 2021 by Kristina Panos 22 Comments

If there’s one bright spot on the blight that is this pandemic, it’s got to be all the extra time we’re spending with our pets. Dogs especially love that we’re home all the time and want to spend it playing, but sometimes you need to get stuff done. Why not head outside with your laptop and keep the dog happy with an automatic ball launcher?

This is a work in progress, and [Connor] plans to publish a BOM and the STL files once it’s all finished. For now, it’s a working prototype that shoots a ball into the air and about 25 feet away, from the looks of it. Far enough to be fun, but not so far that it goes over the fence.

All [Connor] has to do is drop the ball in the top, which you know is going to lead to training the dog to do it himself. A proximity sensor detects the ball and starts up a pair of 540 R/C motors, then a servo drops the ball down the internal chute. The motors spit the ball out with great force with a pair of profiled, 3D-printed wheels that are controlled by a Turnigy ESC and an Arduino Nano.

In the future, [Connor] plans to print a cover for the electronics and enlarge the funnel so it’s easier for the dog to drop in the ball. Check out the brief demo and build video after the break.

All dogs should be able to get in a good game of fetch as often as they want, even if they happen to be blind.

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Remote Controlled Car Gets Active Suspension

April 14, 2021 by Bryan Cockfield 14 Comments

Active suspensions are almost a holy grail for cars, adding so much performance gain that certain types have even been banned from Formula 1 racing. That doesn’t stop them from being used on a wide variety of luxury and performance cars, though, as they can easily be tuned on the fly for comfort or improved handling. They also can be fitted to remote controlled cars as [Indeterminate Design] shows with this electronic servo-operated active suspension system for his RC truck.

Each of the four servos used in this build is linked to the mounting point of the existing coilover suspension on the truck. This allows the servo to change the angle that the suspension is positioned while the truck is moving. As a result, the truck has a dramatic performance enhancement including a tighter turning radius, more stability, and the capability of doing donuts. The control system runs on an Arduino with an ESP32 to enable live streaming of data, and also includes an MPU6050 to monitor the position of the truck’s frame while it is in motion.

There’s a lot going on in this build especially with regard to the control system that handles all of the servos. Right now it’s only programmed to try to keep the truck’s body relatively level, but [Indeterminate Design] plans to program several additional control modes in the future. There’s a lot of considerations to make with a system like this, and even more if you want to accommodate for Rocket League-like jumps. Continue reading “Remote Controlled Car Gets Active Suspension” →

Eyecam Is Watching You In Between Blinks

April 12, 2021 by Kristina Panos 15 Comments

We will be the first to admit that it’s often hard to be productive while working from home, especially if no one’s ever really looking over your shoulder. Well, here is one creepy way to feel as though someone is keeping an eye on you, if that’s what gets you to straighten up and fly right. The Eyecam research project by [Marc Teyssier] et. al. is a realistic, motorized eyeball that includes a camera and hangs out on top of your computer monitor. It aims to spark conversation about the sensors that are all around us already in various cold and clinical forms. It’s an open source project with a paper and a repo and a how-to video in the works.

The eyebrow-raising design pulls no punches in the uncanny department: the eye behaves as you’d expect (if you could have expected this) — it blinks, looks around, and can even waggle its brow. The eyeball, brow, and eyelids are actuated by a total of six servos that are controlled by an Arduino Nano.

Inside the eyeball is a Raspberry Pi camera connected to a Raspi Zero for the web cam portion of this intriguing horror show. Keep an eye out after the break for the Eyecam infomercial.

Creepy or fascinating, it succeeds in making people think about the vast amount of sensors around us now, and what the future of them could look like. Would mimicking eye contact be an improvement over the standard black and gray oblong eye? Perhaps a pair of eyes would be less unsettling, we’re not really sure. But we are left to wonder what’s next, a microphone that looks like an ear? Probably. Will it have hair sprouting from it? Perhaps.

Yeah, it’s true; two eyes are more on the mesmerizing side, but still creepy, especially when they follow you around the room and can shoot frickin’ laser beams.

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Putting Your Time In

March 27, 2021 by Elliot Williams 28 Comments

I was absolutely struck by a hack this week — [Adam Bäckström]’s amazing robot arm built with modified hobby servos. Basically, he’s taken apart and re-built some affordable off-the-shelf servo motors, and like the 6-Million-Dollar Man, he’s rebuilt them better, stronger, faster. OK, and smoother. We have the technology.

The results are undeniably fantastic, and enable the experienced hacker to get champagne robot motion control on a grape-juice budget by employing some heavy control theory, and redundant sensors to overcome geartrain backlash, which is the devil of cheap servos. But this didn’t come out of nowhere. In his writeup, [Adam] starts off with “You could say this project started when I ordered six endless servos in middle school, more than 15 years ago.” And it shows.

Go check out this video of his first version of the modified servos, from a six-axis arm he built in 2009(!). He’s built in analog position sensors in the motors, which lets him control the speed and makes it work better than any other hobby servo arm you’ve ever seen, but there’s still visible backlash in the gears. A mere twelve years later, he’s got magnetic encoders on the output and a fast inner loop compensates for the backlash. The result is that the current arm moves faster and smoother, while retaining accuracy.

Twelve years. I assume that [Adam] has had some other projects on his plate as well, but that’s a long term project by any account. I’m stoked to see his work, not the least because it should help a lot of others who are ready to step up their desktop servo-arm projects. But the real take-home lesson here is that if you’ve got a tough problem that you’re hacking on, you don’t have to get it done this weekend. You don’t have to get it done next weekend either. Keep hammering on it as long as you need, but keep on hammering. When you get it done, the results will be all the better for the long, slow, brewing time. What’s the longest project that you’ve ever worked on?

Coil Winding Machine Makes It Easy

March 24, 2021 by Al Williams 19 Comments

[Mr Innovative] needed to wind some coils, and decided to make a machine to do the work. Making such machines has become a lot easier over the years. There was a time when we might probably have had to hack an old printer or scanner to get linear rods and stepper motors. Now, thanks to widespread 3D printing, we can order parts like that from lots of places. The 3D printing helps, too, to fabricate all the little custom widgets you need to put something like that together.

The machine looks great. It uses a number of parts that would look at home on a 3D printer or CNC build. We thought his Chinese mini table saw did a great job cutting the aluminum extrusions, but we did worry about the safety of his fingers. We’ll admit we are generally lazy and buy the extrusions precut.

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Buttonpusher Automates Animal Crossing Tasks

March 5, 2021 by Donald Papp 6 Comments

Press button, wait, press button again, repeat. There must be a better way! If that kind of interaction drives you nuts, you’ll probably appreciate [Tommy]’s buttonpusher, which has only one job: automate away some of the more boring parts of Nintendo’s Animal Crossing. On one hand the job the device does is very simple: press a button on the Nintendo joy-con in a preprogrammed pattern. There’s no feedback loop, it just dumbly presses and waits. But there are still quite a few interesting bits to this build.

Rigid mounting combined with interfacing the actuator to the servo horn (instead of to the servo shaft) were the keys to reliable button pushing.

For one thing, [Tommy] discovered that the little 9g RC servo can reliably exert enough force to press the button on the joy-con with the right adapter. He had assumed the servo would be too weak to do the job without a greater mechanical advantage, but a simple hammer-style actuator that attaches to the servo horn easily does the job. Well, it does as long as the servo and joy-con are held rigidly; his first version allowed a little too much wiggle in how well the parts were held, and button presses didn’t quite register. With a 3D-printed fixture to rigidly mount both the servo and the joy-con, things were fine.

In the process of making buttonpusher, which uses CircuitPython, [Tommy] created a tool to automate away another pesky task he was running into: circuitpython_tools was created to automatically watch for code changes, convert the .py files into (smaller) MicroPython bytecode .mpy files, then automatically deploy to the board. This saved [Tommy] a lot of time and hassle during development, but it was only necessary because he quickly ran out of memory on his M0 Metro Express board, and couldn’t fit his code in any other way.

Still, it’s a good example of how one project can sometimes spawn others, and lead to all kinds of lessons learned. You can see buttonpusher automate the crafting process in Animal Crossing in the video, embedded below.

Continue reading “Buttonpusher Automates Animal Crossing Tasks” →